Old Publications

Recent Publications

2009

abstract
bibtex
Ning, K. and Wörgötter, F.
A DOF state controllable and driving shared solution for building a hyper-redundant chain robot
IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2009
This paper puts forward a novel design solution for building a 3D hyper-redundant chain robot HRCR system, which consists of linked, identical modules and one base module. All the joints of this HRCR are passive and state controllable, and share common inputs introduced by wire-driven control, no matter how many degrees of freedom DOF are implemented using different numbers of modules. The prototype developed here, named 3D-Trunk, is used as a proof of concept. We will present here its concept, mechanical and embedded controller design and the implementation
@inproceedings{ningwoergoetter2009a, title: {A DOF state controllable and driving shared solution for building a hyper-redundant chain robot}, author: {Ning, K. and Wörgötter, F.}, year: {2009}, booktitle: {IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, journal: {}, }
abstract
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Butz, M. and Wörgötter, F.
A Model for Cortical Rewiring Following Deafferentation and Focal Stroke
Front. Comput. Neurosci , 2009
It is still unclear to what extent structural plasticity in terms of synaptic rewiring is the cause for cortical remapping after a lesion. Recent two-photon laser imaging studies demonstrate that synaptic rewiring is persistent in the adult brain and is dramatically increased following brain lesions or after a loss of sensory input cortical deafferentation. We use a recurrent neural network model to study the time course of synaptic rewiring following a peripheral lesion. For this, we represent axonal and dendritic elements of cortical neurons to model synapse formation, pruning and synaptic rewiring. Neurons increase and decrease the number of axonal and dendritic elements in an activity-dependent fashion in order to maintain their activity in a homeostatic equilibrium. In this study we demonstrate that synaptic rewiring contributes to neuronal homeostasis during normal development as well as following lesions. We show that networks in homeostasis, which can therefore be considered as adult networks, are much less able to compensate for a loss of input. Interestingly, we found that paused stimulation of the networks are much more effective promoting reorganization than continuous stimulation. This can be explained as neurons quickly adapt to this stimulation whereas pauses prevents a saturation of the positive stimulation effect. These findings may suggest strategies for improving therapies in neurologic rehabilitation
@article{butzwoergoetter2009, title: {A Model for Cortical Rewiring Following Deafferentation and Focal Stroke}, author: {Butz, M. and Wörgötter, F.}, year: {2009}, booktitle: {}, journal: {Front. Comput. Neurosci}, }
abstract
bibtex
Ning, K. and Wörgötter, F.
A Novel Concept for Building a Hyper-Redundant Chain Robot
IEEE Transactions on Robotics , 2009
This paper puts forward a novel design concept for building a 3-D hyper-redundant chain robot HRCR system, con- sisting of linked, identical modules and one base module. All the joints of this HRCR are passive and state controllable and share common inputs introduced by wire-driven control. The original prototype developed here, named 3D-Trunk, is used as a proof of concept. We will present its whole mechanical design and con- troller architecture. The key components of 3D-Trunk, its opera- tional principles, and all implementation issues are exhibited and described in detail. Basic robotics analyses, dynamics simulations, and some experiments are also shown. This novel design concept is highly modular and scalable, no matter how many degrees of free- dom are implemented and, thus, provides an affordable solution for constructing an HRCR
@article{ningwoergoetter2009, title: {A Novel Concept for Building a Hyper-Redundant Chain Robot}, author: {Ning, K. and Wörgötter, F.}, year: {2009}, booktitle: {}, journal: {IEEE Transactions on Robotics}, }
abstract
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Butz, M. and Wörgötter, F. and Ooyen, A.
Activity-dependent structural plasticity
Brain Research Reviews , 2009
@article{butzworgotterooyen2009, title: {Activity-dependent structural plasticity}, author: {Butz, M. and Wörgötter, F. and Ooyen, A.}, year: {2009}, booktitle: {}, journal: {Brain Research Reviews}, }
abstract
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Manoonpong, P. and Wörgötter, F.
Adaptive Sensor-Driven Neural Control for Learning in Walking Machines
Neural Information Processing, 2009
Wild rodents learn the danger-predicting meaning of preda- tor bird calls through the paring of cues which are an aversive stimulus immediate danger signal or unconditioned stimulus, US and the acous- tic stimulus predator signal or conditioned stimulus, CS. This learning is a form of pavlovian conditioning. In analogy, in this article a setup is described where adaptive sensor-driven neural control is used to simulate biologically-inspired acoustic predator-recognition learning for a safe es- cape on a six-legged walking machine. As a result, the controller allows the walking machine to learn the association of a predictive acoustic sig- nal predator signal, CS and a reflex infrared signal immediate danger signal, US. Such that after learning the machine performs fast walking behavior when hearing an approaching predator from behind leading to safely escape from the attack
@inproceedings{manoonpongwoergoetter2009a, title: {Adaptive Sensor-Driven Neural Control for Learning in Walking Machines}, author: {Manoonpong, P. and Wörgötter, F.}, year: {2009}, booktitle: {Neural Information Processing}, journal: {}, }
abstract
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Markelic, I. and Kulvicius, T. and Tamosiunaite, M. and Wörgötter, F.
Anticipatory Driving for a Robot-Car Based on Supervised Learning
Lecture Notes in Computer Science: Anticipatory Behavior in Adaptive Learning Systems , 2009
Using look ahead information and plan making improves hu- man driving. We therefore propose that also autonomously driving systems should dispose over such abilities. We adapt a machine learning approach, where the system, a car-like robot, is trained by an experienced driver by correlating visual input to human driving actions. The heart of the system is a database where look ahead sensory information is stored together with action sequences issued by the human supervi- sor. The result is a robot that runs at real-time and issues steering and velocity control in a human-like way. For steer we adapt a two-level ap- proach, where the result of the database is combined with an additional reactive controller for robust behavior. Concerning velocity control this paper makes a novel contribution which is the ability of the system to react adequatly to upcoming curves
@article{markelickulviciustamosiunaite2009, title: {Anticipatory Driving for a Robot-Car Based on Supervised Learning}, author: {Markelic, I. and Kulvicius, T. and Tamosiunaite, M. and Wörgötter, F.}, year: {2009}, booktitle: {}, journal: {Lecture Notes in Computer Science: Anticipatory Behavior in Adaptive Learning Systems}, }
abstract
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Wörgötter, F. and Agostini, A. and Krüger, N. and Shylo, N. and Porr, B.
Cognitive agents - a procedural perspective relying on the predictability of Object-Action-Complexes OACs
Robotics and Autonomous Systems , 2009
Embodied cognition suggests that complex cognitive traits can only arise when agents have a body situated in the world. The aspects of embodiment and situatedness are being discussed here from the perspective of linear systems theory. This perspective treats bodies as dynamic, temporally variable entities, which can be extended or curtailed at their boundaries. We show how acting agents can, for example, actively extend their body for some time by incorporating predictably behaving parts of the world and how this affects the transfer functions. We suggest that primates have mastered this to a large degree increasingly splitting their world into predictable and unpredictable entities. We argue that temporary body extension may have been instrumental in paving the way for the development of higher cognitive complexity as it is reliably widening the cause-effect horizon about the actions of the agent. A first robot experiment is sketched to support these ideas. We continue discussing the concept of Object-Action Complexes OACs introduced by the European PACO-PLUS consortium to emphasize the notion that, for a cognitive agent, objects and actions are inseparably intertwined. In another robot experiment we devise a semi-supervised procedure using the OAC-concept to demonstrate how an agent can acquire knowledge about its world. Here the notion of predicting changes fundamentally underlies the implemented procedure and we try to show how this concept can be used to improve the robots inner model and behaviour. Hence, in this article we have tried to show how predictability can be used to augment the agents body and to acquire knowledge about the external world, possibly leading to more advanced cognitive traits
@article{woergoetteragostinikrueger2009, title: {Cognitive agents - a procedural perspective relying on the predictability of Object-Action-Complexes OACs}, author: {Wörgötter, F. and Agostini, A. and Krüger, N. and Shylo, N. and Porr, B.}, year: {2009}, booktitle: {}, journal: {Robotics and Autonomous Systems}, }
abstract
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Dellen, B. and Wörgötter, F.
Disparity from stereo-segment silhouettes of weakly-textured images
British Machine Vision Conference, 2009
We propose a novel robust stereo algorithm for weakly-textured scenes. Unique cor- respondences existing between the silhouettes of corresponding image segments allow assigning accurate disparities to segment boundary points. This information as well as stereo from the weak texture inside segments, which is extracted using a region- constrained window-based matching algorithm, are fused and disparities are interpolated inside segments while considering potentially occluded areas derived from the depth- ordering of segments. The algorithm is applied to a set of weakly-textured images and it is demonstrated that stereo from segment silhouettes often provides sufficient informa- tion to reconstruct disparities in weakly- and non-textured image areas. The algorithm is applied to several real stereo images and its performance is evaluated quantitatively using images from the 2006 Middlebury dataset
@inproceedings{dellenwoergoetter2009, title: {Disparity from stereo-segment silhouettes of weakly-textured images}, author: {Dellen, B. and Wörgötter, F.}, year: {2009}, booktitle: {British Machine Vision Conference}, journal: {}, }
abstract
bibtex
Manoonpong, P. and Wörgötter, F.
Efference copies in neural control of dynamic biped walking
Robotics and Autonomous Systems , 2009
In the early 1950s, von Holst and Mittelstaedt proposed that motor commands copied within the central nervous system efference copy help to distinguish reafference activity afference activity due to self- generated motion from exafference activity afference activity due to external stimulus. In addition, an efference copy can be also used to compare it with the actual sensory feedback in order to suppress self- generated sensations. Based on these biological findings, we conduct here two experimental studies on our biped RunBot where such principles together with neural forward models are applied to RunBots dynamic locomotion control. The main purpose of this article is to present the modular design of RunBots control architecture and discuss how the inherent dynamic properties of the different modules lead to the required signal processing. We believe that the experimental studies pursued here will sharpen our understanding of how the efference copies influence dynamic locomotion control to the benefit of modern neural control strategies in robots
@article{manoonpongwoergoetter2009, title: {Efference copies in neural control of dynamic biped walking}, author: {Manoonpong, P. and Wörgötter, F.}, year: {2009}, booktitle: {}, journal: {Robotics and Autonomous Systems}, }
abstract
bibtex
Agostini, A. and Celaya, E.
Exploiting Domain Symmetries in Reinforcement Learning with Continuous State and Action Spaces
Proc. 8th International Conference on Machine Learning and Applications ICMLA09. Miami, EE.UU, 2009
@conference{agostinicelaya2009, title: {Exploiting Domain Symmetries in Reinforcement Learning with Continuous State and Action Spaces}, author: {Agostini, A. and Celaya, E.}, year: {2009}, booktitle: {Proc. 8th International Conference on Machine Learning and Applications ICMLA09. Miami, EE.UU}, journal: {}, }
abstract
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Tamosiunaite, M. and Asfour, T. and Wörgötter, F.
Learning to reach by reinforcement learning using a receptive field based function approximation approach with continuous actions
Biological Cybernetics , 2009
Reinforcement learning methods can be used in robotics applications especially for specific target-oriented problems, for example the reward-based recalibration of goal directed actions. To this end still relatively large and continuous state-action spaces need to be efficiently handled. The goal of this paper is, thus, to develop a novel, rather simple method which uses reinforcement learning with function approximation in conjunction with different reward-strategies for solving such problems. For the testing of our method, we use a four degree-of-freedom reaching problem in 3D-space simulated by a two-joint robot arm system with two DOF each. Function approximation is based on 4D, overlapping kernels receptive fields and the state-action space contains about 10,000 of these. Different types of reward structures are being compared, for example, reward-on- touching-only against reward-on-approach. Furthermore, forbidden joint configurations are punished. A continuous action space is used. In spite of a rather large number of states and the continuous action space these reward/punishment strategies allow the system to find a good solution usually within about 20 trials. The efficiency of our method demonstrated in this test scenario suggests that it might be possible to use it on a real robot for problems where mixed rewards can be defined in situations where other types of learning might be difficult
@article{tamosiunaiteasfourwoergoetter2009, title: {Learning to reach by reinforcement learning using a receptive field based function approximation approach with continuous actions}, author: {Tamosiunaite, M. and Asfour, T. and Wörgötter, F.}, year: {2009}, booktitle: {}, journal: {Biological Cybernetics}, }
abstract
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Kolodziejski, C. and Porr, B. and Wörgötter, F.
On the Asymptotic Equivalence Between Differential Hebbian and Temporal Difference Learning
Neural Computation , 2009
In this theoretical contribution, we provide mathematical proof that two of the most important classes of network learning correlation-based differential Hebbian learning and reward-based temporal difference learning are asymptotically equivalent when timing the learning with a modulatory signal. This opens the opportunity to consistently refor- mulate most of the abstract reinforcement learning framework from a correlation-based perspective more closely related to the biophysics of neurons
@article{kolodziejskiporrwoergoetter2009, title: {On the Asymptotic Equivalence Between Differential Hebbian and Temporal Difference Learning}, author: {Kolodziejski, C. and Porr, B. and Wörgötter, F.}, year: {2009}, booktitle: {}, journal: {Neural Computation}, }
abstract
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Kolodziejski, C. and Porr, B. and Tamosiunaite, M. and Wörgötter, F.
On the asymptotic equivalence between differential Hebbian and temporal difference learning using a local third factor
Advances in Neural Information Processing Systems, 2009
In this theoretical contribution we provide mathematical proof that two of the most important classes of network learning - correlation-based differential Heb- bian learning and reward-based temporal difference learning - are asymptotically equivalent when timing the learning with a local modulatory signal. This opens the opportunity to consistently reformulate most of the abstract reinforcement learn- ing framework from a correlation based perspective that is more closely related to the biophysics of neurons
@inproceedings{kolodziejskiporrtamosiunaite2009, title: {On the asymptotic equivalence between differential Hebbian and temporal difference learning using a local third factor}, author: {Kolodziejski, C. and Porr, B. and Tamosiunaite, M. and Wörgötter, F.}, year: {2009}, booktitle: {Advances in Neural Information Processing Systems}, journal: {}, }
abstract
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Baseski, E. and Baunegaard With Jensen, L. and Pugeault, N. and Pilz, F. and Pauwels, K. and Hulle, M V. and Wörgötter, F. and Krüger, N.
Road Interpretation for Driver Assistance based on an Early Cognitive Vision System
VISAPP, 2009
In this work, we address the problem of road interpretation for driver assistance based on an early cognitive vision system. The structure of a road and the relevant traffic are interpreted in terms of ego-motion estimation of the car, independently moving objects on the road, lane markers and large scale maps of the road. We make use of temporal and spatial disambiguation mechanisms to increase the reliability of visually extracted 2D and 3D information. This information is then used to interpret the layout of the road by using lane markers that are detected via Bayesian reasoning. We also estimate the ego-motion of the car which is used to create large scale maps of the road and also to detect independently moving objects. Sample results for the presented algorithms are shown on a stereo image sequence, that has been collected from a structured road
@inproceedings{baseskibaunegaardwithjensenpugeault, title: {Road Interpretation for Driver Assistance based on an Early Cognitive Vision System}, author: {Baseski, E. and Baunegaard With Jensen, L. and Pugeault, N. and Pilz, F. and Pauwels, K. and Hulle, M V. and Wörgötter, F. and Krüger, N.}, year: {2009}, booktitle: {VISAPP}, journal: {}, }
abstract
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Dellen, B. and Aksoy, E E. and Wörgötter, F.
Segment Tracking via a Spatiotemporal Linking Process including Feedback Stabilization in an n-D Lattice Model
Sensors , 2009
Model-free tracking is important for solving tasks such as moving-object tracking and action recognition in cases where no prior object knowledge is available. For this purpose, we extend the concept of spatially synchronous dynamics in spin-lattice models to the spatiotemporal domain to track segments within an image sequence. The method is related to synchronization processes in neural networks and based on superparamagnetic clustering of data. Spin interactions result in the formation of clusters of correlated spins, providing an automatic labeling of corresponding image regions. The algorithm obeys detailed balance. This is an important property as it allows for consistent spin-transfer across subsequent frames, which can be used for segment tracking. Therefore, in the tracking process the correct equilibrium will always be found, which is an important advance as compared with other more heuristic tracking procedures. In the case of long image sequences, i.e. and movies, the algorithm is augmented with a feedback mechanism, further stabilizing segment tracking
@article{dellenaksoywoergoetter2009, title: {Segment Tracking via a Spatiotemporal Linking Process including Feedback Stabilization in an n-D Lattice Model}, author: {Dellen, B. and Aksoy, E E. and Wörgötter, F.}, year: {2009}, booktitle: {}, journal: {Sensors}, }
abstract
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Dellen, B. and Wörgötter, F.
Simulating Dynamical Systems for Early Vision
VISAPP, 2009
We propose a novel algorithm for stereo matching using a dynamical systems approach. The stereo correspon- dence problem is first formulated as an energy minimization problem. From the energy function, we derive a system of differential equations describing the corresponding dynamical system of interacting elements, which we solve using numerical integration. Optimization is introduced by means of a damping term and a noise term, an idea similar to simulated annealing. The algorithm is tested on the Middlebury stereo benchmark
@inproceedings{dellenwoergoetter2009a, title: {Simulating Dynamical Systems for Early Vision}, author: {Dellen, B. and Wörgötter, F.}, year: {2009}, booktitle: {VISAPP}, journal: {}, }
abstract
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Nemec, B. and Tamosiunaite, M. and Wörgötter, F. and Ude, A.
Task adaptation through exploration and action sequencing
9th IEEE-RAS International Conference on Humanoid Robots, 2009, 2009
General-purpose autonomous robots need to have the ability to sequence and adapt the available sensorimotor knowledge, which is often given in the form of movement primitives. In order to solve a given task in situations that were not considered during the initial learning, it is necessary to adapt trajectories contained in the library of primitive motions to new situations. In this paper we explore how to apply reinforcement learning to modify the subgoals of primitive movements involved in the given task. As the underlying sensorimotor representation we selected nonlinear dynamic systems, which provide a powerful machinery for the modification of motion trajectories. We propose a new formulation for dynamic systems, which ensures that consecutive primitive movements can be splined together in a continuous way up to second order derivatives
@inproceedings{nemectamosiunaitewoergoetter2009, title: {Task adaptation through exploration and action sequencing}, author: {Nemec, B. and Tamosiunaite, M. and Wörgötter, F. and Ude, A.}, year: {2009}, booktitle: {9th IEEE-RAS International Conference on Humanoid Robots, 2009}, journal: {}, }
abstract
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Renjewski, D. and Seyfarth, A. and Manoonpong, P. and Wörgötter, F.
The development of a biomechanical leg system and its neural control
IEEE International Conference on Robotics and Biomimetics ROBIO, 2009
The function of the locomotor system in human gait is still an open question. Today robot bipeds are not able to reproduce the versatility of human locomotion. In this article a robotic knee joint and an experimental setup are proposed. The leg function is tested and the acquired data is compared to human leg behaviour in running observed in experiments
@inproceedings{renjewskiseyfarthmanoonpong2009, title: {The development of a biomechanical leg system and its neural control}, author: {Renjewski, D. and Seyfarth, A. and Manoonpong, P. and Wörgötter, F.}, year: {2009}, booktitle: {IEEE International Conference on Robotics and Biomimetics ROBIO}, journal: {}, }

2008

abstract
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Kalkan, S. and Wörgötter, F. and Krüger, N.
A Signal-Symbol Loop Mechanism for Enhanced Edge Extraction
In Int. Conf. on Computer Vision Theory and Applications VISAPP08, 2008
The transition to symbolic information from images involves in general the loss or misclassification of infor- mation. One way to deal with this missing or wrong information is to get feedback from concrete hypotheses derived at a symbolic level to the sub-symbolic signal stage to amplify weak information or correct misclas- sifications. This paper proposes such a feedback mechanism between the symbolic level and the signal level, which we call signal symbol loop. We apply this framework for the detection of low contrast edges making use of predictions based on Rigid Body Motion. Once the Rigid Body Motion is known, the location and the properties of edges at a later frame can be predicted. We use these predictions as feedback to the signal level at a later frame to improve the detection of low contrast edges. We demonstrate our mechanism on a real example, and evaluate the results using an artificial scene, where the ground truth data is available
@inproceedings{kalkanwoergoetterkrueger2008a, title: {A Signal-Symbol Loop Mechanism for Enhanced Edge Extraction}, author: {Kalkan, S. and Wörgötter, F. and Krüger, N.}, year: {2008}, booktitle: {In Int. Conf. on Computer Vision Theory and Applications VISAPP08}, journal: {}, }
abstract
bibtex
Agostini, A. and Celaya, E. and Torras, C. and Wörgötter, F.
Action Rule Induction from Cause-Effect Pairs Learned through Robot-Teacher Interaction
International Conference on Cognitive Systems COGSYS, 2008
In this work we propose a decision-making system that efficiently learns behaviors in the form of rules using natural human instructions about cause-effect relations in currently observed situations, avoiding complicated instructions and explanations of long-run action sequences and complete world dynamics. The learned rules are represented in a way suitable to both reactive and deliberative approaches, which are thus smoothly integrated. Simple and repetitive tasks are resolved reactively, while complex tasks would be faced in a more deliberative manner using a planner module. Human interaction is only required if the system fails to obtain the expected results when applying a rule, or fails to resolve the task with the knowledge acquired so far
@inproceedings{agostinicelayatorras2008, title: {Action Rule Induction from Cause-Effect Pairs Learned through Robot-Teacher Interaction}, author: {Agostini, A. and Celaya, E. and Torras, C. and Wörgötter, F.}, year: {2008}, booktitle: {International Conference on Cognitive Systems COGSYS}, journal: {}, }
abstract
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Shylo, N. and Wörgötter, F. and Dellen, B.
Ascertaining relevant changes in visual data by interfacing AI reasoning and low-level visual information via temporally stable image segments
In Proceedings of the International Conference on Cognitive Systems, 2008
Action planning and robot control require logical operations to be performed on sensory information, i.e. images of the world as seen by a camera consisting of continuous values of pixels. Artificial intelligence AI planning algorithms however use symbolic descriptors such as objects and actions to define logic rules and future actions. The representational differences at these distinct processing levels have to be bridged in order to allow communication between both levels. In this paper, we suggest a novel framework for interfacing AI planning with low-level visual processing by transferring the visual data into a discrete symbolic representation of temporally stable image segments. At the AI planning level, action-relevant changes in the configuration of image segments are inferred from a set of experiments using the Group Method of Data Handling. We apply the method to a data set obtained by repeating an action in an abstract scenario for varying initial conditions, determining the success or failure of the action. From the set of experiments, joint representations of actions and objects are extracted, which capture the rules of the given scenario
@inproceedings{shylowoergoetterdellen2008, title: {Ascertaining relevant changes in visual data by interfacing AI reasoning and low-level visual information via temporally stable image segments}, author: {Shylo, N. and Wörgötter, F. and Dellen, B.}, year: {2008}, booktitle: {In Proceedings of the International Conference on Cognitive Systems}, journal: {}, }
abstract
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Manoonpong, P. and Wörgötter, F.
Biologically-Inspired Reactive Walking Machine AMOS-WD06
In Proceedings of 4th International Symposium on Adaptive Motion of Animals and Machines AMAM2008, 2008
The six-legged walking machine AMOS-WD061 see Fig. 1A is a hardware platform for studying the coordination of many degrees of freedom, for performing experiments with neural controllers, and for the development of artificial perception-action systems
@inproceedings{manoonpongwoergoetter2008a, title: {Biologically-Inspired Reactive Walking Machine AMOS-WD06}, author: {Manoonpong, P. and Wörgötter, F.}, year: {2008}, booktitle: {In Proceedings of 4th International Symposium on Adaptive Motion of Animals and Machines AMAM2008}, journal: {}, }
abstract
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Kraft, D. and Pugeault, N. and Baseski, E. and Popovic, M. and Kragic, D. and Kalkan, S. and Wörgötter, F. and Krüger, N.
Birth of the Object: Detection of Objectness and Extraction of Object Shape through Object-Action complexes
Inf. J. Humanoid Robotics , 2008
We describe a process in which the segmentation of objects as well as the extraction of the object shape becomes realized through active exploration of a robot vision system. In the exploration process, two behavioral modules that link robot actions to the visual and haptic perception of objects interact. First, by making use of an object independent grasping mechanism, physical control over potential objects can be gained. Having evaluated the initial grasping mechanism as being successful, a second behavior extracts the object shape by making use of prediction based on the motion induced by the robot. This also leads to the concept of an object as a set of features that change predictably over different frames. The system is equipped with a certain degree of generic prior knowledge about the world in terms of a sophisticated visual feature extraction process in an early cognitive vision system, knowledge about its own embodiment as well as knowledge about geomet- ric relationships such as rigid body motion. This prior knowledge allows the extraction of representations that are semantically richer compared to many other approaches
@article{kraftpugeaultbaseski2008, title: {Birth of the Object: Detection of Objectness and Extraction of Object Shape through Object-Action complexes}, author: {Kraft, D. and Pugeault, N. and Baseski, E. and Popovic, M. and Kragic, D. and Kalkan, S. and Wörgötter, F. and Krüger, N.}, year: {2008}, booktitle: {}, journal: {Inf. J. Humanoid Robotics}, }
abstract
bibtex
Jensen, L. and Baseski, E. and Kalkan, S. and Pugeault, N. and Wörgötter, F. and Krüger, N.
Cognitive Vision
Cognitive Vision, 2008
In this paper, we propose a hierarchical architecture for representing scenes, covering 2D and 3D aspects of visual scenes as well as the semantic relations between the different aspects. We argue that labeled graphs are a suitable representational framework for this representation and demonstrate its potential by two applications. As a first application, we localize lane structures by the semantic descriptors and their relations in a Bayesian framework. As the second application, which is in the context of vision based grasping, we show how the semantic re- lations can be associated to actions that allow for grasping without using any object knowledge
@incollection{jensenbaseskikalkan2008, title: {Cognitive Vision}, author: {Jensen, L. and Baseski, E. and Kalkan, S. and Pugeault, N. and Wörgötter, F. and Krüger, N.}, year: {2008}, booktitle: {Cognitive Vision}, journal: {}, }
abstract
bibtex
Kalkan, S. and Wörgötter, F. and Krüger, N.
Depth Prediction at Homogeneous Image Structures
In Int. Conf. on Computer Vision Theory and Applications VISAPP08, 2008
This paper proposes a voting-based model that predicts depth at weakly-structured image areas from the depth that is extracted using a feature-based stereo method. We provide results, on both real and artificial scenes, that show the accuracy and robustness of our approach. Moreover, we compare our method to different dense stereo algorithms to investigate the effect of texture on performance of the two different approaches. The results confirm the expectation that dense stereo methods are suited better for textured image areas and our method for weakly-textured image areas
@inproceedings{kalkanwoergoetterkrueger2008, title: {Depth Prediction at Homogeneous Image Structures}, author: {Kalkan, S. and Wörgötter, F. and Krüger, N.}, year: {2008}, booktitle: {In Int. Conf. on Computer Vision Theory and Applications VISAPP08}, journal: {}, }
abstract
bibtex
Kraft, D. and Baseski, E. and Popovic, M. and Batog, A M. and Kjaer-Nielsen, A. and Krüger, N. and Petrick, R. and Geib, C. and Pugeault N., S. and Asfour, T. and Dillmann, R. and Kalkan Sand Wörgötter, F. and B., H. and Detry, R. and Piater, J.
Exploration and Planning in a Three-Level Cognitive Architecture
International Conference on Cognitive Systems COGSYS, 2008
We describe an embodied cognitive system based on a three-level architecture that includes a sensorimotor layer, a mid-level layer that stores and reasons about object-action episodes, and a high-level symbolic planner that creates abstract action plans to be realised and possibly further specified by the lower levels. The system works in two modes, exploration and plan execution, that both make use of the same architecture. We give results of different sub-processes as well as their interaction. In particular, we describe the generation and execution of plans as well as a set of learning processes that take place independently of, or in parallel with, plan execution
@inproceedings{kraftbaseskipopovic2008, title: {Exploration and Planning in a Three-Level Cognitive Architecture}, author: {Kraft, D. and Baseski, E. and Popovic, M. and Batog, A M. and Kjaer-Nielsen, A. and Krüger, N. and Petrick, R. and Geib, C. and Pugeault N., S. and Asfour, T. and Dillmann, R. and Kalkan Sand Wörgötter, F. and B., H. and Detry, R. and Piater, J.}, year: {2008}, booktitle: {International Conference on Cognitive Systems COGSYS}, journal: {}, }
abstract
bibtex
Renjewski, D. and Manoonpong, P. and Seyfarth, A. and Wörgötter, F.
From Biomechanical Concepts Towards Fast And Robust Robots
Advances in Mobile Robotics: Proc. of 11th CLAWAR, Marques L, Almeida A, Tokhi MO, Virk GS Eds., World Scientific, 2008
Robots of any kind, highly integrated mechatronic systems, are smart combina- tions of mechanics, electronics and information technology. The development of bipedal robots in particular, which perform human-like locomotion, challenges scientists on even higher levels. Facing this challenge, this article presents a biomimetic bottom-up approach to use knowledge of biomechanical experiments on human walking and running, computer simulation and neuronal control concepts to sequentially design highly adaptable and compliant walking machines
@inproceedings{renjewskimanoonpongseyfarth2008, title: {From Biomechanical Concepts Towards Fast And Robust Robots}, author: {Renjewski, D. and Manoonpong, P. and Seyfarth, A. and Wörgötter, F.}, year: {2008}, booktitle: {Advances in Mobile Robotics: Proc. of 11th CLAWAR, Marques L, Almeida A, Tokhi MO, Virk GS Eds., World Scientific}, journal: {}, }
abstract
bibtex
Wörgötter, F.
Lernende Systeme
In Georgia Augusta Wissenschaftsmagazin der Universität Göttingen , 2008
@article{woergoetter2008, title: {Lernende Systeme}, author: {Wörgötter, F.}, year: {2008}, booktitle: {}, journal: {In Georgia Augusta Wissenschaftsmagazin der Universität Göttingen}, }
abstract
bibtex
Kolodziejski, C. and Porr, B. and Wörgötter, F.
Mathematical properties of neuronal TD-rules and differential Hebbian learning: a comparison
Biological Cybernetics , 2008
A confusingly wide variety of temporally asym- metric learning rules exists related to reinforcement learning and/or to spike-timing dependent plasticity, many of which look exceedingly similar, while displaying strongly different behavior. These rules often find their use in control tasks, for example in robotics and for this rigorous convergence and numerical stability is required. The goal of this article is to review these rules and compare them to provide a better over- view over their different properties. Two main classes will be discussed: temporal difference TD rules and correlation based differential hebbian rules and some transition cases. In general we will focus on neuronal implementations with changeable synaptic weights and a time-continuous represen- tation of activity. In a machine learning non-neuronal con- text, for TD-learning a solid mathematical theory has existed since several years. This can partly be transfered to a neu- ronal framework, too. On the other hand, only now a more complete theory has also emerged for differential Hebb rules. In general rules differ by their convergence conditions and their numerical stability, which can lead to very undesirable behavior, when wanting to apply them. For TD, convergence can be enforced with a certain output condition assuring that the
@article{kolodziejskiporrwoergoetter2008, title: {Mathematical properties of neuronal TD-rules and differential Hebbian learning: a comparison}, author: {Kolodziejski, C. and Porr, B. and Wörgötter, F.}, year: {2008}, booktitle: {}, journal: {Biological Cybernetics}, }
abstract
bibtex
Manoonpong, P. and Wörgötter, F.
Neural Control for Locomotion of Walking Machines
In Proceedings of 4th International Symposium on Adaptive Motion of Animals and Machines AMAM2008, 2008
The basic locomotion and rhythm of stepping in walking animals like cockroaches mostly relies on a central pattern generator CPG 1, while their peripheral sensors are used to control walking behaviors 2. By contrast, in stick insects, sensory feedback serving as reflexive mechanism plays a critical role in shaping the motor pattern for adaptivity and robustness of walking gaits 2. Inspired by the principles of biological locomotion control, two different types of neural mechanism for locomotion control of walking machines are presented. One is called modular reactive neural control and the other is adaptive reflex neural control
@inproceedings{manoonpongwoergoetter2008b, title: {Neural Control for Locomotion of Walking Machines}, author: {Manoonpong, P. and Wörgötter, F.}, year: {2008}, booktitle: {In Proceedings of 4th International Symposium on Adaptive Motion of Animals and Machines AMAM2008}, journal: {}, }
abstract
bibtex
Kulvicius, T. and Tamosiunaite, M. and Ainge, J. and Dudchenko, P. and Wörgötter, F.
Odor supported place cell model and goal navigation in rodents
Journal of Computational Neuroscience , 2008
Experiments with rodents demonstrate that visual cues play an important role in the control of hippocampal place cells and spatial navigation. Never- theless, rats may also rely on auditory, olfactory and somatosensory stimuli for orientation. It is also known that rats can track odors or self-generated scent marks to find a food source. Here we model odor supported place cells by using a simple feed-forward network and analyze the impact of olfactory cues on place cell formation and spatial navigation. The obtained place cells are used to solve a goal navigation task by a novel mechanism based on self-marking by odor patches combined with a Q-learning algorithm. We also analyze the impact of place cell remapping on goal directed behavior when switching between two environments. We emphasize the importance of olfactory cues in place cell formation and show that the utility of environ- mental and self-generated olfactory cues, together with a mixed navigation strategy, improves goal directed navigation
@article{kulviciustamosiunaiteainge2008, title: {Odor supported place cell model and goal navigation in rodents}, author: {Kulvicius, T. and Tamosiunaite, M. and Ainge, J. and Dudchenko, P. and Wörgötter, F.}, year: {2008}, booktitle: {}, journal: {Journal of Computational Neuroscience}, }
abstract
bibtex
Tamosiunaite, M. and Ainge, J. and Kulvicius, T. and Porr, B. and Dudchenko, P. and Wörgötter, F.
Path-finding in real and simulated rats: assessing the influence of path characteristics on navigation learning
Journal of Computational Neuroscience , 2008
A large body of experimental evidence suggests that the hippocampal place field system is involved in reward based navigation learning in rodents. Reinforcement learning RL mechanisms have been used to model this, associating the state space in an RL-algorithm to the place-field map in a rat. The convergence properties of RL-algorithms are affected by the exploration patterns of the learner. Therefore, we first analyzed the path characteristics of freely exploring rats in a test arena. We found that straight path segments with mean length 23 cm up to a maximal length of 80 cm take up a significant proportion of the total paths. Thus, rat paths are biased as compared to random exploration. Next we designed a RL system that reproduces these specific path characteristics. Our model arena is covered by overlapping, probabilistically firing place fields PF of realistic size and coverage. Because convergence of RL-algorithms is also influenced by the state space characteristics, different PF-sizes and densities, leading to a different degree of overlap, were also investigated. The model rat learns finding a reward opposite to its starting point. We observed that the combination of biased straight exploration, overlapping coverage and probabilistic firing will strongly impair the convergence of learning. When the degree of randomness in the exploration is increased, convergence improves, but the distribution of straight path segments becomes unrealistic and paths become wiggly. To mend this situation without affecting the path characteristic two additional mechanisms are implemented: A gradual drop of the learned weights weight decay and path length limitation, which prevents learning if the reward is not found after some expected time. Both mechanisms limit the memory of the system and thereby counteract effects of getting trapped on a wrong path. When using these strategies individually divergent cases get substantially reduced and for some parameter settings no divergence was found anymore at all. Using weight decay and path length limitation at the same time, convergence is not much improved but instead time to convergence increases as the memory limiting effect is getting too strong. The degree of improvement relies also on the size and degree of overlap coverage density in the place field system. The used combination of these two parameters leads to a trade-off between convergence and speed to convergence. Thus, this study suggests that the role of the PF-system in navigation learning cannot be considered independently from the animals exploration pattern
@article{tamosiunaiteaingekulvicius2008, title: {Path-finding in real and simulated rats: assessing the influence of path characteristics on navigation learning}, author: {Tamosiunaite, M. and Ainge, J. and Kulvicius, T. and Porr, B. and Dudchenko, P. and Wörgötter, F.}, year: {2008}, booktitle: {}, journal: {Journal of Computational Neuroscience}, }
abstract
bibtex
Wörgötter, F. and Porr, B.
Reinforcement learning
Scholarpedia , 2008
@article{woergoetterporr2008, title: {Reinforcement learning}, author: {Wörgötter, F. and Porr, B.}, year: {2008}, booktitle: {}, journal: {Scholarpedia}, }
abstract
bibtex
Pugeault, N. and Kalkan, S. and Baseski, E. and Wörgötter, F. and Krüger, N.
Relations Between Reconstructed 3D Entities
In Int. Conf. on Computer Vision Theory and Applications VISAPP08, 2008
In this paper, we first propose an analytic formulation for the positions and orientations uncertainty of local 3D line descriptors reconstructed by stereo. We evaluate these predicted uncertainties with Monte Carlo simulations, and study their dependency on different parameters position and orientation. In a second part, we use this definition to derive a new formulation for interfeatures distance and coplanarity. These new formulations take into account the predicted uncertainty, allowing for better robustness. We demonstrate the positive effect of the modified definitions on some simple scenarios
@inproceedings{pugeaultkalkanbaeski2008, title: {Relations Between Reconstructed 3D Entities}, author: {Pugeault, N. and Kalkan, S. and Baseski, E. and Wörgötter, F. and Krüger, N.}, year: {2008}, booktitle: {In Int. Conf. on Computer Vision Theory and Applications VISAPP08}, journal: {}, }
abstract
bibtex
Thompson, A M. and Porr, B. and Kolodziejski, C. and Wörgötter, F.
Second Order Conditioning in the Sub-cortical Nuclei of the Limbic System
From Animals to Animats 10, 2008
Three factor Isotropic sequence order ISO3 learning is a form of differential Hebbian learning where a third factor switches on learning at relevant moments for example, after reward retreival. This switch enables learning only at specific moments and, thus, stablises the corresponding weights. The concept of using a third factor as a gating signal for learning at relevant moments has been extended in this pa- per to perform second order conditioning SOC. We present a biological model of the sub-cortical nuclei of the limbic system that is capable of performing SOC in a food seeking task. The 3rd-factor is modelled by dopaminergic neurons of the VTA which are activated via a direct exci- tatory glutamatergic pathway, and an indirect dis-inhibitory GABAergic pathway. The latter generates an amplification in the number of tonically active DA neurons. This produces an increase in DA outside the event of a primary reward and enables SOC to be accomplished
@inproceedings{thompsonporrkolodziejski2008, title: {Second Order Conditioning in the Sub-cortical Nuclei of the Limbic System}, author: {Thompson, A M. and Porr, B. and Kolodziejski, C. and Wörgötter, F.}, year: {2008}, booktitle: {From Animals to Animats 10}, journal: {}, }
abstract
bibtex
Manoonpong, P. and Pasemann, F. and Wörgötter, F.
Sensor-driven neural control for omnidirectional locomotion and versatile reactive behaviors of walking machines
Robotics and Autonomous Systems , 2008
This article describes modular neural control structures for different walking machines utilizing discrete-time neurodynamics. A simple neural oscillator network serves as a central pattern generator producing the basic rhythmic leg movements. Other modules, like the velocity regulating and the phase switching networks, enable the machines to perform omnidirectional walking as well as reactive behaviors, like obstacle avoidance and different types of tropisms. These behaviors are generated in a sensori-motor loop with respect to appropriate sensor inputs, to which a neural preprocessing is applied. The neuromodules presented are small so that their structure function relationship can be analysed. The complete controller is general in the sense that it can be easily adapted to different types of even-legged walking machines without changing its internal structure and parameters
@article{manoonpongpasemannwoergoetter2008, title: {Sensor-driven neural control for omnidirectional locomotion and versatile reactive behaviors of walking machines}, author: {Manoonpong, P. and Pasemann, F. and Wörgötter, F.}, year: {2008}, booktitle: {}, journal: {Robotics and Autonomous Systems}, }
abstract
bibtex
Manoonpong, P. and Wörgötter, F.
Using efference copy for external and self-generated sensory noise cancellation
Proceedings of 4th International Symposium on Adaptive Motion of Animals and Machines, Case Western Reserve University, Cleveland OH-USA, 2008
@inproceedings{manoonpongwoergoetter2008, title: {Using efference copy for external and self-generated sensory noise cancellation}, author: {Manoonpong, P. and Wörgötter, F.}, year: {2008}, booktitle: {Proceedings of 4th International Symposium on Adaptive Motion of Animals and Machines, Case Western Reserve University, Cleveland OH-USA}, journal: {}, }

2007

abstract
bibtex
Baseski, E. and Pugeault, N. and Kalkan, S. and Kraft, D. and Wörgötter, F. and Krüger, N.
A Scene Representation Based on Multi-Modal 2D and 3D Features
ICCV 2007 Workshop on 3D Representation for Recognition 3dRR-07, 2007
@inproceedings{baseskipugeaultkalkan2007, title: {A Scene Representation Based on Multi-Modal 2D and 3D Features}, author: {Baseski, E. and Pugeault, N. and Kalkan, S. and Kraft, D. and Wörgötter, F. and Krüger, N.}, year: {2007}, booktitle: {ICCV 2007 Workshop on 3D Representation for Recognition 3dRR-07}, journal: {}, }
abstract
bibtex
Manoonpong, P. and Geng, T. and Porr, B. and Kulvicius, T. and Wörgötter, F.
Adaptive, Fast Walking in a Biped Robot under Neuronal Control and Learning
Public Library of Science Computational Biology PLoS Comp. Biol., 37, e134 , 2007
Human walking is a dynamic, partly self-stabilizing process relying on the interaction of the biomechanical design with its neuronal control. The coordination of this process is a very difficult problem, and it has been suggested that it involves a hierarchy of levels, where the lower ones, e.g., interactions between muscles and the spinal cord, are largely autonomous, and where higher level control (e.g., cortical) arises only pointwise, as needed. This requires an architecture of several nested, sensori-motor loops where the walking process provides feedback signals to the walkers sensory systems, which can be used to coordinate its movements. To complicate the situation, at a maximal walking speed of more than four leg-lengths per second, the cycle period available to coordinate all these loops is rather short. In this study we present a planar biped robot, which uses the design principle of nested loops to combine the self-stabilizing properties of its biomechanical design with several levels of neuronal control. Specifically, we show how to adapt control by including online learning mechanisms based on simulated synaptic plasticity. This robot can walk with a high speed (3.0 leg length/s), self-adapting to minor disturbances, and reacting in a robust way to abruptly induced gait changes. At the same time, it can learn walking on different terrains, requiring only few learning experiences. This study shows that the tight coupling of physical with neuronal control, guided by sensory feedback from the walking pattern itself, combined with synaptic learning may be a way forward to better understand and solve coordination problems in other complex motor tasks.
@article{manoonponggengporr2007a, title: {Adaptive, Fast Walking in a Biped Robot under Neuronal Control and Learning}, author: {Manoonpong, P. and Geng, T. and Porr, B. and Kulvicius, T. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Public Library of Science Computational Biology PLoS Comp. Biol., 37, e134}, }
abstract
bibtex
Kolodziejski, C. and Porr, B. and Wörgötter, F.
Anticipative adaptive muscle control: forward modeling with self-induced disturbances and recruitment
BMC Neuroscience , 2007
@article{kolodziejskiporrwoergoetter2007, title: {Anticipative adaptive muscle control: forward modeling with self-induced disturbances and recruitment}, author: {Kolodziejski, C. and Porr, B. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {BMC Neuroscience}, }
abstract
bibtex
Kulvicius, T. and Bernd, P. and Wörgötter, F.
Chained learning architectures in a simple closed-loop behavioural context
Biol. Cybern , 2007
@article{kulviciusberndwoergoetter2007, title: {Chained learning architectures in a simple closed-loop behavioural context}, author: {Kulvicius, T. and Bernd, P. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Biol. Cybern}, }
abstract
bibtex
Wischmann, S. and Pasemann, F. and Wörgötter, F.
Cooperation and competition: Neural mechanisms of evolved communication systems
Workshop on The Emergence of Social Behaviour / CD-ROM : From Cooperation to Language. Lisbon, Portugal, 2007
@inproceedings{wischmannpasemannwoergoetter2007, title: {Cooperation and competition: Neural mechanisms of evolved communication systems}, author: {Wischmann, S. and Pasemann, F. and Wörgötter, F.}, year: {2007}, booktitle: {Workshop on The Emergence of Social Behaviour / CD-ROM : From Cooperation to Language. Lisbon, Portugal}, journal: {}, }
abstract
bibtex
Tamosiunaite, M. and Porr, B. and Wörgötter, F.
Developing velocity sensitivity in a model neuron by local synaptic plasticity
Biol. Cybern , 2007
@article{tamosiunaiteporrwoergoetter2007, title: {Developing velocity sensitivity in a model neuron by local synaptic plasticity}, author: {Tamosiunaite, M. and Porr, B. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Biol. Cybern}, }
abstract
bibtex
Kulvicius, T. and Porr, B. and Wörgötter, F.
Development of Receptive Fields in a Closed-loop Behavioural System
Neurocomput , 2007
@article{kulviciusporrwoergoetter2007, title: {Development of Receptive Fields in a Closed-loop Behavioural System}, author: {Kulvicius, T. and Porr, B. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Neurocomput}, }
abstract
bibtex
Hennig, M H. and Wörgötter, F.
Effects of fixational eye movements on retinal ganglion cell responses: a modelling study
Front. Comput. Neurosci , 2007
@article{hennigwoergoetter2007, title: {Effects of fixational eye movements on retinal ganglion cell responses: a modelling study}, author: {Hennig, M H. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Front. Comput. Neurosci}, }
abstract
bibtex
Wischmann, S. and Stamm, K. and Wörgötter, F.
Embodied evolution and learning: The neglected timing of maturation
Advances in Artificial Life: 9th European Conference on Artificial Life, ECAL, Almeidae Costa, F. and Rocha, L. M. and Costa, E. and Harvey, I. and Coutinho, A. eds. Springer Series: LNAI, 4648, 2007
@inproceedings{wischmannstammwoergoetter2007, title: {Embodied evolution and learning: The neglected timing of maturation}, author: {Wischmann, S. and Stamm, K. and Wörgötter, F.}, year: {2007}, booktitle: {Advances in Artificial Life: 9th European Conference on Artificial Life, ECAL, Almeidae Costa, F. and Rocha, L. M. and Costa, E. and Harvey, I. and Coutinho, A. eds. Springer Series: LNAI, 4648}, journal: {}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Fast heterosynaptic learning in a robot food retrieval task inspired by the limbic system
BioSystems , 2007
@article{porrwoergoetter2007, title: {Fast heterosynaptic learning in a robot food retrieval task inspired by the limbic system}, author: {Porr, B. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {BioSystems}, }
abstract
bibtex
Kalkan, S. and Wörgötter, F. and Krüger, N.
First-order and Second-order Statistical Analysis of 3D and 2D Structure, Network
Computation in Neural Systems, 2007
@inproceedings{kalkanwoergoetterkrueger2007, title: {First-order and Second-order Statistical Analysis of 3D and 2D Structure, Network}, author: {Kalkan, S. and Wörgötter, F. and Krüger, N.}, year: {2007}, booktitle: {Computation in Neural Systems}, journal: {}, }
abstract
bibtex
Ainge, J. and Tamosiunaite, M. and Wörgötter, F. and Dudchenko, P.
Hippocampal CA1 place cells encode intended destination on a maze with multiple choice points
J. Neurosci , 2007
@article{aingetamosiunaitewoergoetter2007, title: {Hippocampal CA1 place cells encode intended destination on a maze with multiple choice points}, author: {Ainge, J. and Tamosiunaite, M. and Wörgötter, F. and Dudchenko, P.}, year: {2007}, booktitle: {}, journal: {J. Neurosci}, }
abstract
bibtex
Thompson, A. and Porr, B. and Egerton, A. and Wörgöter, F.
How bursting and tonic dopaminergic activity generates LTP and LTD
BMC Neuroscience , 2007
@article{thompsonporregerton2007, title: {How bursting and tonic dopaminergic activity generates LTP and LTD}, author: {Thompson, A. and Porr, B. and Egerton, A. and Wörgöter, F.}, year: {2007}, booktitle: {}, journal: {BMC Neuroscience}, }
abstract
bibtex
Porr, B. and Kulvicius, T. and Wörgötter, F.
Improved stability and convergence with three factor learning
Neurocomputing , 2007
@article{porrkulviciuswoergoetter2007, title: {Improved stability and convergence with three factor learning}, author: {Porr, B. and Kulvicius, T. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Neurocomputing}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Learning with Relevance: Using a third factor to stabilize Hebbian learning
Neural Comp , 2007
@article{porrwoergoetter2007a, title: {Learning with Relevance: Using a third factor to stabilize Hebbian learning}, author: {Porr, B. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Funke, K. and Kerscher, N J. and Wörgötter, F.
Noise-improved signal detection in cat primary visual cortex via a well balanced stochastic resonance like process
Europ. J. Neurosci , 2007
@article{funkekerscherwoergoetter2007, title: {Noise-improved signal detection in cat primary visual cortex via a well balanced stochastic resonance like process}, author: {Funke, K. and Kerscher, N J. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Europ. J. Neurosci}, }
abstract
bibtex
Manoonpong, P. and Pasemann, F. and Wörgötter, F.
Reactive Neural Control for Phototaxis and Obstacle Avoidance Behavior of Walking Machines
Proceedings of World Academy of Science, Engineering and Technology PWASET, International conference on Intelligent systems ICIS 07, Bangkok, Thailand, December, 2007
@inproceedings{manoonpongpasemannwoergoetter2007, title: {Reactive Neural Control for Phototaxis and Obstacle Avoidance Behavior of Walking Machines}, author: {Manoonpong, P. and Pasemann, F. and Wörgötter, F.}, year: {2007}, booktitle: {Proceedings of World Academy of Science, Engineering and Technology PWASET, International conference on Intelligent systems ICIS 07, Bangkok, Thailand, December}, journal: {}, }
abstract
bibtex
Tamosiunaite, M. and Porr, B. and Wörgötter, F.
Self-influencing synaptic plasticity: Recurrent changes of synaptic weights can lead to specific functional properties
Journal of Computational Neuroscience , 2007
Recent experimental results suggest that dendritic and back-propagating spikes can influence synaptic plastic- ity in different ways Holthoff, 2004: Holthoff et al. and 2005. In this study we investigate how these signals could interact at dendrites in space and time leading to changing plasticity properties at local synapse clusters. Similar to a previous study Saudargiene et al. and 2004 we employ a differential Hebbian learning rule to emulate spike-timing dependent plasticity and investigate how the interaction of dendritic and back-propagating spikes, as the post-synaptic signals, could influence plasticity. Specifically, we will show that lo- cal synaptic plasticity driven by spatially confined dendritic spikes can lead to the emergence of synaptic clusters with different properties. If one of these clusters can drive the neu- ron into spiking, plasticity may change and the now arising global influence of a back-propagating spike can lead to a further segregation of the clusters and possibly the dying-off of some of them leading to more functional specificity. These results suggest that through plasticity being a spatial and tem- poral local process, the computational properties of dendrites or complete neurons can be substantially augmented
@article{tamosiunaiteporrwoergoetter2007a, title: {Self-influencing synaptic plasticity: Recurrent changes of synaptic weights can lead to specific functional properties}, author: {Tamosiunaite, M. and Porr, B. and Wörgötter, F.}, year: {2007}, booktitle: {}, journal: {Journal of Computational Neuroscience}, }
abstract
bibtex
Kalkan, S. and Wörgötter, F. and Krüger, N.
Statistical Analysis of Second-order Relations of 3D Structures
International Conference on Computer Vision Theory and Applications VISAPP, 2007
@inproceedings{kalkanwoergoetterkrueger2007a, title: {Statistical Analysis of Second-order Relations of 3D Structures}, author: {Kalkan, S. and Wörgötter, F. and Krüger, N.}, year: {2007}, booktitle: {International Conference on Computer Vision Theory and Applications VISAPP}, journal: {}, }
abstract
bibtex
Manoonpong, P. and Geng, T. and Porr, B. and Wörgötter, F.
The RunBot architecture for adaptive, fast, dynamic walking
IEEE International Symposium on Circuits and Systems ISCAS, New Orleans, USA, 2007
@inproceedings{manoonponggengporr2007, title: {The RunBot architecture for adaptive, fast, dynamic walking}, author: {Manoonpong, P. and Geng, T. and Porr, B. and Wörgötter, F.}, year: {2007}, booktitle: {IEEE International Symposium on Circuits and Systems ISCAS, New Orleans, USA}, journal: {}, }

2006

abstract
bibtex
Yang Z, M. and Wörgötter, F. and Cameron, K. and Boonsobhak, V.
A neuromorphic depth-from-motion vision model with STDP adaptation
IEEE Trans. Neural Networks , 2006
@article{yangzwoergoettercameron2006, title: {A neuromorphic depth-from-motion vision model with STDP adaptation}, author: {Yang Z, M. and Wörgötter, F. and Cameron, K. and Boonsobhak, V.}, year: {2006}, booktitle: {}, journal: {IEEE Trans. Neural Networks}, }
abstract
bibtex
Geng, T. and Porr, B. and Wörgötter, F.
Coupling of neural computation with physical computation for stable dynamic biped walking control
Neural Comp , 2006
@article{gengporrwoergoetter2006, title: {Coupling of neural computation with physical computation for stable dynamic biped walking control}, author: {Geng, T. and Porr, B. and Wörgötter, F.}, year: {2006}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Krüger, N. and Wörgötter, F. and Hulle, M V.
Editorial: ECOVISION: Challenges in Early-Cognitive Vision
Int. J. Comp. Vision , 2006
@article{kruegerwoergoetterhulle2006, title: {Editorial: ECOVISION: Challenges in Early-Cognitive Vision}, author: {Krüger, N. and Wörgötter, F. and Hulle, M V.}, year: {2006}, booktitle: {}, journal: {Int. J. Comp. Vision}, }
abstract
bibtex
Manoonpong, P. and Geng, T. and Wörgötter, F.
Exploring the dynamic walking range of the biped robot Runbot with an active upper-body component
IEEE-RAS International Conference on Humanoid Robots Humanoids 2006, 2006
@inproceedings{manoonponggengwoergoetter2006, title: {Exploring the dynamic walking range of the biped robot Runbot with an active upper-body component}, author: {Manoonpong, P. and Geng, T. and Wörgötter, F.}, year: {2006}, booktitle: {IEEE-RAS International Conference on Humanoid Robots Humanoids 2006}, journal: {}, }
abstract
bibtex
Geng, T. and Porr, B. and Wörgötter, F.
Fast biped walking with a reflexive controller and real-time policy searching
Advances in Neural Information Processing, 2006
@inproceedings{gengporrwoergoetter2006a, title: {Fast biped walking with a reflexive controller and real-time policy searching}, author: {Geng, T. and Porr, B. and Wörgötter, F.}, year: {2006}, booktitle: {Advances in Neural Information Processing}, journal: {}, }
abstract
bibtex
Geng, T. and Porr, B. and Wörgötter, F.
Fast biped walking with a reflexive neuronal controller and real-time online learning
Int. Journal of Robotics Res , 2006
@article{gengporrwoergoetter2006b, title: {Fast biped walking with a reflexive neuronal controller and real-time online learning}, author: {Geng, T. and Porr, B. and Wörgötter, F.}, year: {2006}, booktitle: {}, journal: {Int. Journal of Robotics Res}, }
abstract
bibtex
Henning, M. and Wörgötter, F.
Influence of retinal ganglion cell nonlinearities on visual perception
Journal of Vision , 2006
@article{henningwoergoetter2006, title: {Influence of retinal ganglion cell nonlinearities on visual perception}, author: {Henning, M. and Wörgötter, F.}, year: {2006}, booktitle: {}, journal: {Journal of Vision}, }
abstract
bibtex
Pugeault, N. and Wörgötter, F. and Krüger, N.
Multi-modal Primitives: Local, Condensed, and Semantically Rich Visual Descriptors and the Formalisation of Contextual Information
International Journal of Humanoid Robotics, Special Issue on Cognitive Humanoidd Vision , 2006
We present a novel representation of visual information, based on local symbolic descriptors, that we call visual primitives. These primitives: (1) combine different visual modalities, (2) associate semantic to local scene information, and (3) reduce the bandwidth while increasing the predictability of the information exchanged across the system. This representation leads to the concept of early cognitive vision that we define as an intermediate level between dense, signal-based early vision and high-level cognitive vision. The frameworks potential is demonstrated in several applications, in particular in the area of robotics and humanoid robotics, which are briefly outlined. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0219843610002209
@article{pugeaultwoergoetterkrueger2006, title: {Multi-modal Primitives: Local, Condensed, and Semantically Rich Visual Descriptors and the Formalisation of Contextual Information}, author: {Pugeault, N. and Wörgötter, F. and Krüger, N.}, year: {2006}, booktitle: {}, journal: {International Journal of Humanoid Robotics, Special Issue on Cognitive Humanoidd Vision}, }
abstract
bibtex
Pugeault, N. and Wörgötter, F. and Krüger, N.
Multi-modal scene reconstruction using perceptual grouping constraints
Computer Vision and Pattern Recognition Workshop, CVPRW, 2006
@inproceedings{pugeaultwoergoetterkrueger2006a, title: {Multi-modal scene reconstruction using perceptual grouping constraints}, author: {Pugeault, N. and Wörgötter, F. and Krüger, N.}, year: {2006}, booktitle: {Computer Vision and Pattern Recognition Workshop, CVPRW}, journal: {}, }
abstract
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Geib, C. and Mourao, K. and Petrick, R. and Pugeault, N. and Steedman, M. and Krüger, N. and Wörgötter, F.
Object Action Complexes as an Interface for Planning and Robot Control
IEEE-RAS International Conference on Humanoid Robots Workshop at the Humanoids 2006, Genova, Italy, 2006
@inproceedings{geibmouraopetrick2006, title: {Object Action Complexes as an Interface for Planning and Robot Control}, author: {Geib, C. and Mourao, K. and Petrick, R. and Pugeault, N. and Steedman, M. and Krüger, N. and Wörgötter, F.}, year: {2006}, booktitle: {IEEE-RAS International Conference on Humanoid Robots Workshop at the Humanoids 2006, Genova, Italy}, journal: {}, }
abstract
bibtex
Kulvicius, T. and Geng, T. and Porr, B. and Wörgötter, F.
Speed Optimization of a 2D Walking Robot through STDP
Dynamical principles for neuroscience and intelligennt biomimetic devices: EPFL LATSIS Symposium 2006, 2006
@inproceedings{kulviciusgengporr2006, title: {Speed Optimization of a 2D Walking Robot through STDP}, author: {Kulvicius, T. and Geng, T. and Porr, B. and Wörgötter, F.}, year: {2006}, booktitle: {Dynamical principles for neuroscience and intelligennt biomimetic devices: EPFL LATSIS Symposium 2006}, journal: {}, }
abstract
bibtex
Thompson, A M. and Porr, B. and Wörgötter, F.
Stabilising Hebbian learning with a third factor in a food retrieval task
SAB 2006, Lecture Notes in Computer Science, 2006
@inproceedings{thompsonporrwoergoetter2006, title: {Stabilising Hebbian learning with a third factor in a food retrieval task}, author: {Thompson, A M. and Porr, B. and Wörgötter, F.}, year: {2006}, booktitle: {SAB 2006, Lecture Notes in Computer Science}, journal: {}, }
abstract
bibtex
Kalkan S. Wörgötter, F. and Krüger, N.
Statistical Analysis of Local 3D Structure in 2D Images
IEEE Computer Vision and Pattern Recognition CVPR, 2006
@inproceedings{kalkanswoergoetterkrueger2006, title: {Statistical Analysis of Local 3D Structure in 2D Images}, author: {Kalkan S. Wörgötter, F. and Krüger, N.}, year: {2006}, booktitle: {IEEE Computer Vision and Pattern Recognition CVPR}, journal: {}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Strongly improved stability and faster convergence of temporal sequence learning by utilising input correlations only
Neural Comp , 2006
@article{porrwoergoetter2006, title: {Strongly improved stability and faster convergence of temporal sequence learning by utilising input correlations only}, author: {Porr, B. and Wörgötter, F.}, year: {2006}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Symbolic Pointillism: Computer art motivated by human brain structures
Leonardo , 2006
@article{kruegerwoergoetter2006, title: {Symbolic Pointillism: Computer art motivated by human brain structures}, author: {Krüger, N. and Wörgötter, F.}, year: {2006}, booktitle: {}, journal: {Leonardo}, }
abstract
bibtex
Tamosiunaite, M. and Porr, B. and Wörgötter, F.
Temporally changing synaptic plasticity
Advances in Neural Information Processing Systems, 18, 2006
@inproceedings{tamosiunaiteporrwoergoetter2006, title: {Temporally changing synaptic plasticity}, author: {Tamosiunaite, M. and Porr, B. and Wörgötter, F.}, year: {2006}, booktitle: {Advances in Neural Information Processing Systems, 18}, journal: {}, }
abstract
bibtex
Porr, B. and Egerton, A. and Wörgötter, F.
Towards closed loop information: Predictive information
Constructivist Foundat , 2006
@article{porregertonwoergoetter2006, title: {Towards closed loop information: Predictive information}, author: {Porr, B. and Egerton, A. and Wörgötter, F.}, year: {2006}, booktitle: {}, journal: {Constructivist Foundat}, }

2005

abstract
bibtex
Calow, D. and Krüger, N. and Wörgötter, F. and Lappe, M.
Biologically motivated space-variant filtering for robust optic flow processing
Network , 2005
@article{calowkruegerwoergoetter2005, title: {Biologically motivated space-variant filtering for robust optic flow processing}, author: {Calow, D. and Krüger, N. and Wörgötter, F. and Lappe, M.}, year: {2005}, booktitle: {}, journal: {Network}, }
abstract
bibtex
Agostini, A. and Celaya, E.
Feasible Control of Complex Systems using Automatic Learning
Proc. of the 2nd International Conference on Informatics in Control, Automation and Robotics ICINCO05. Barcelona, Spain, 2005
@conference{agostinicelaya2005, title: {Feasible Control of Complex Systems using Automatic Learning}, author: {Agostini, A. and Celaya, E.}, year: {2005}, booktitle: {Proc. of the 2nd International Conference on Informatics in Control, Automation and Robotics ICINCO05. Barcelona, Spain}, journal: {}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Inside Embodiment What means Embodiment for Radical Constructivists
Kybernetes , 2005
@article{porrwoergoetter2005, title: {Inside Embodiment What means Embodiment for Radical Constructivists}, author: {Porr, B. and Wörgötter, F.}, year: {2005}, booktitle: {}, journal: {Kybernetes}, }
abstract
bibtex
Kalkan, S. and Calow, D. and Wörgötter, F. and Lappe, M. and Krüger, N.
Local image structures and optic flow estimation
Network , 2005
@article{kalkancalowwoergoetter2005, title: {Local image structures and optic flow estimation}, author: {Kalkan, S. and Calow, D. and Wörgötter, F. and Lappe, M. and Krüger, N.}, year: {2005}, booktitle: {}, journal: {Network}, }
abstract
bibtex
Saudargiene, A. and Porr, B. and Wörgötter, F.
Local learning rules: Predicted influence of dendritic location on synaptic modification in spike timing dependent plasticity
Biol. Cybern , 2005
@article{saudargieneporrwoergoetter2005a, title: {Local learning rules: Predicted influence of dendritic location on synaptic modification in spike timing dependent plasticity}, author: {Saudargiene, A. and Porr, B. and Wörgötter, F.}, year: {2005}, booktitle: {}, journal: {Biol. Cybern}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Multi-modal primitives as functional models of hyper-columns and their use for contextual integration
Proc. 1st Int. Symp. Brain, Vision and Artificial Intelligence, Lecture Notes in Computer Science, 2005
@inproceedings{kruegerwoergoetter2005, title: {Multi-modal primitives as functional models of hyper-columns and their use for contextual integration}, author: {Krüger, N. and Wörgötter, F.}, year: {2005}, booktitle: {Proc. 1st Int. Symp. Brain, Vision and Artificial Intelligence, Lecture Notes in Computer Science}, journal: {}, }
abstract
bibtex
Saudargiene, A. and Porr, B. and Wörgötter, F.
Synaptic modifications depend on synapse location and activity: a biophysical model of STDP
Biosystems , 2005
@article{saudargieneporrwoergoetter2005, title: {Synaptic modifications depend on synapse location and activity: a biophysical model of STDP}, author: {Saudargiene, A. and Porr, B. and Wörgötter, F.}, year: {2005}, booktitle: {}, journal: {Biosystems}, }
abstract
bibtex
Kulvicius, T. and Tamosiunaite, M. and Vaisnys, R.
T Wave Alternans Features for Automated Detection
Informatica , 2005
@article{kulviciustamosiunaitevaisnys2005, title: {T Wave Alternans Features for Automated Detection}, author: {Kulvicius, T. and Tamosiunaite, M. and Vaisnys, R.}, year: {2005}, booktitle: {}, journal: {Informatica}, }
abstract
bibtex
Wörgötter, F. and Porr, B.
Temporal sequence learning, prediction and control - A review of different models and their relation to biological mechanisms
Neural Comp , 2005
@article{woergoetterporr2005, title: {Temporal sequence learning, prediction and control - A review of different models and their relation to biological mechanisms}, author: {Wörgötter, F. and Porr, B.}, year: {2005}, booktitle: {}, journal: {Neural Comp}, }

2004

abstract
bibtex
Pugeault, N. and Wörgötter, F. and Krüger, N.
A non-local stereo similarity based on collinear groups
Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal, 2004
@inproceedings{pugeaultwoergoetterkrueger2004, title: {A non-local stereo similarity based on collinear groups}, author: {Pugeault, N. and Wörgötter, F. and Krüger, N.}, year: {2004}, booktitle: {Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal}, journal: {}, }
abstract
bibtex
Wörgötter, F.
Actor-Critic Models of Animal Control - A critique of reinforcement learning
Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal, 2004
@inproceedings{woergoetter2004, title: {Actor-Critic Models of Animal Control - A critique of reinforcement learning}, author: {Wörgötter, F.}, year: {2004}, booktitle: {Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal}, journal: {}, }
abstract
bibtex
Porr, B. and Saudargiene, A. and Wörgötter, F.
Analytical solution of spike-timing dependent plasticity based on synaptic biophysics
Advances in Neural Information Processing Systems 16. Thrun, S. and Saul, L. and Schölkopf, B. eds. MIT Press, 2004
@inproceedings{porrsaudargienewoergoetter2004, title: {Analytical solution of spike-timing dependent plasticity based on synaptic biophysics}, author: {Porr, B. and Saudargiene, A. and Wörgötter, F.}, year: {2004}, booktitle: {Advances in Neural Information Processing Systems 16. Thrun, S. and Saul, L. and Schölkopf, B. eds. MIT Press}, journal: {}, }
abstract
bibtex
Saudargiene, A. and Porr, B. and Wörgötter, F.
Biologically inspired artificial neural network algorithm which implements local learning rules
ISCAS, Vancouver, 2004
@inproceedings{saudargieneporrwoergoetter2004, title: {Biologically inspired artificial neural network algorithm which implements local learning rules}, author: {Saudargiene, A. and Porr, B. and Wörgötter, F.}, year: {2004}, booktitle: {ISCAS, Vancouver}, journal: {}, }
abstract
bibtex
Krüger, N. and Lappe, M. and Wörgötter, F.
Biologically motivated multi-modal processing of visual primitives
The Interdisciplinary Journal of Artificial Intelligence and the Simulation of Behaviour , 2004
@article{kruegerlappewoergoetter2004, title: {Biologically motivated multi-modal processing of visual primitives}, author: {Krüger, N. and Lappe, M. and Wörgötter, F.}, year: {2004}, booktitle: {}, journal: {The Interdisciplinary Journal of Artificial Intelligence and the Simulation of Behaviour}, }
abstract
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Wörgötter, F. and Krüger, N. and Pugeault, N. and Calow, D. and Lappe, M. and Pauwels, K. and Hulle, M V. and Tan, S. and Johnston, A.
Early cognitive vision: Using Gestalt laws for task-dependent, active image processing
Natural Computing , 2004
@article{woergoetterkruegerpugeault2004, title: {Early cognitive vision: Using Gestalt laws for task-dependent, active image processing}, author: {Wörgötter, F. and Krüger, N. and Pugeault, N. and Calow, D. and Lappe, M. and Pauwels, K. and Hulle, M V. and Tan, S. and Johnston, A.}, year: {2004}, booktitle: {}, journal: {Natural Computing}, }
abstract
bibtex
Hennig, M. and Wörgötter, F.
Eye micro-movements improve stimulus detection beyond the Nyquist limit in the peripheral retina
Advances in Neural Information Processing Systems, 2004
@inproceedings{hennigwoergoetter2004, title: {Eye micro-movements improve stimulus detection beyond the Nyquist limit in the peripheral retina}, author: {Hennig, M. and Wörgötter, F.}, year: {2004}, booktitle: {Advances in Neural Information Processing Systems}, journal: {}, }
abstract
bibtex
Saudargiene, A. and Porr, B. and Wörgötter, F.
How the shape of pre- and postsynaptic signals can influence STDP: A biophysical model
Neural Comp , 2004
@article{saudargieneporrwoergoetter2004a, title: {How the shape of pre- and postsynaptic signals can influence STDP: A biophysical model}, author: {Saudargiene, A. and Porr, B. and Wörgötter, F.}, year: {2004}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Agostini, A. and Celaya, E.
Learning Model-Free Motor Control
Proc. of the 16th European Conference on Artificial intelligence ECAI04. Valencia, Spain, 2004
@conference{agostinicelaya2004a, title: {Learning Model-Free Motor Control}, author: {Agostini, A. and Celaya, E.}, year: {2004}, booktitle: {Proc. of the 16th European Conference on Artificial intelligence ECAI04. Valencia, Spain}, journal: {}, }
abstract
bibtex
Agostini, A. and Celaya, E.
Learning in Complex Environments with Feature-Based Categorization
Proc. of the 8th Conference on Intelligent Autonomous Systems IAS8. Amsterdam, Netherlands, 2004
@conference{agostinicelaya2004, title: {Learning in Complex Environments with Feature-Based Categorization}, author: {Agostini, A. and Celaya, E.}, year: {2004}, booktitle: {Proc. of the 8th Conference on Intelligent Autonomous Systems IAS8. Amsterdam, Netherlands}, journal: {}, }
abstract
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Kalkan, S. and Calow, D. and Felsberg, M. and Wörgötter, F. and Lappe, M. and Krüger, N.
Optic flow statistics and intrinsic dimensionality
Brain Inspired Cognitive Systems, 2004
@inproceedings{kalkancalowfelsberg2004, title: {Optic flow statistics and intrinsic dimensionality}, author: {Kalkan, S. and Calow, D. and Felsberg, M. and Wörgötter, F. and Lappe, M. and Krüger, N.}, year: {2004}, booktitle: {Brain Inspired Cognitive Systems}, journal: {}, }
abstract
bibtex
Krüger, N. and Felsberg, M. and Wörgötter, F.
Processing multi-modal primitives from image sequences
Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal, 2004
@inproceedings{kruegerfelsbergwoergoetter2004, title: {Processing multi-modal primitives from image sequences}, author: {Krüger, N. and Felsberg, M. and Wörgötter, F.}, year: {2004}, booktitle: {Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal}, journal: {}, }
abstract
bibtex
Calow, D. and Krüger, N. and Wörgötter, F. and Lappe, M.
Space variant filtering of optic flow for robust three dimensional motion estimation
Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal, 2004
@inproceedings{calowkruegerwoergoetter2004, title: {Space variant filtering of optic flow for robust three dimensional motion estimation}, author: {Calow, D. and Krüger, N. and Wörgötter, F. and Lappe, M.}, year: {2004}, booktitle: {Fourth International ICSC Symposium on Engineering of Intelligent Systems, Madeira, Portugal}, journal: {}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Statistical and deterministic regularities: Utilization of motion and grouping in biological and artificial visual systems
Advances in Imaging and Electron Physics , 2004
@article{kruegerwoergoetter2004, title: {Statistical and deterministic regularities: Utilization of motion and grouping in biological and artificial visual systems}, author: {Krüger, N. and Wörgötter, F.}, year: {2004}, booktitle: {}, journal: {Advances in Imaging and Electron Physics}, }
abstract
bibtex
Agostini, A. and Celaya, E.
Trajectory Tracking Control of a Rotational Joint using Feature-Based Categorization Learning
Proc. International Conference on Intelligent Robots and Systems IROS04. Sendai, Japan, 2004
@conference{agostinicelaya2004b, title: {Trajectory Tracking Control of a Rotational Joint using Feature-Based Categorization Learning}, author: {Agostini, A. and Celaya, E.}, year: {2004}, booktitle: {Proc. International Conference on Intelligent Robots and Systems IROS04. Sendai, Japan}, journal: {}, }

2003

abstract
bibtex
Porr, B. and Ferber, C. and Wörgötter, F.
ISO-learning approximates a solution to the inverse controller problem in an unsupervised behavioural paradigm
Neural Comp , 2003
@article{porrferberwoergoetter2003, title: {ISO-learning approximates a solution to the inverse controller problem in an unsupervised behavioural paradigm}, author: {Porr, B. and Ferber, C. and Wörgötter, F.}, year: {2003}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Inside Embodiment - Control from the Organisms Point of View
, 2003
@misc{porrwoergoetter2003d, title: {Inside Embodiment - Control from the Organisms Point of View}, author: {Porr, B. and Wörgötter, F.}, year: {2003}, booktitle: {}, journal: {}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Interaction, self-reference and contingency in computational neuroscience: analytical descriptions and information theoretic consequences
Rethinking Communicative Interaction: New interdisciplinary horizons, Colin B. Grant, Ed., John Benjamins Publ. Co. and Amsterdam, Philadelphia, 2003
@inproceedings{porrwoergoetter2003a, title: {Interaction, self-reference and contingency in computational neuroscience: analytical descriptions and information theoretic consequences}, author: {Porr, B. and Wörgötter, F.}, year: {2003}, booktitle: {Rethinking Communicative Interaction: New interdisciplinary horizons, Colin B. Grant, Ed., John Benjamins Publ. Co. and Amsterdam, Philadelphia}, journal: {}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Isotropic sequence order learning
Neural Comp , 2003
@article{porrwoergoetter2003c, title: {Isotropic sequence order learning}, author: {Porr, B. and Wörgötter, F.}, year: {2003}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Isotropic sequence order learning in a closed loop behavioural system
Roy. Soc. Phil. Trans. Mathematical, Physical and Engineering Sciences , 2003
@article{porrwoergoetter2003b, title: {Isotropic sequence order learning in a closed loop behavioural system}, author: {Porr, B. and Wörgötter, F.}, year: {2003}, booktitle: {}, journal: {Roy. Soc. Phil. Trans. Mathematical, Physical and Engineering Sciences}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Learning a forward model of a reflex
MIT Press Advances in Neural Information Processing Systems 15, 2003
@inproceedings{porrwoergoetter2003, title: {Learning a forward model of a reflex}, author: {Porr, B. and Wörgötter, F.}, year: {2003}, booktitle: {Advances in Neural Information Processing Systems 15}, journal: {MIT Press}, }
abstract
bibtex
Wörgötter, F. and Suder, K. and Funke, K.
Response characteristics in the lateral geniculate nucleus and their primary afferent influences on the visual cortex of cat. In: Modulation of Neuronal Responses: Implications for Active Vision. G.T. Buracas, O. Ruksenas, G.M. Boyton and T.D. Albright, eds
NATO Science , 2003
@article{woergoettersuderfunke2003, title: {Response characteristics in the lateral geniculate nucleus and their primary afferent influences on the visual cortex of cat. In: Modulation of Neuronal Responses: Implications for Active Vision. G.T. Buracas, O. Ruksenas, G.M. Boyton and T.D. Albright, eds}, author: {Wörgötter, F. and Suder, K. and Funke, K.}, year: {2003}, booktitle: {}, journal: {NATO Science}, }
abstract
bibtex
Eyding, D. and Macklis, J D. and Neubacher, U. and Funke, K. and Wörgötter, F.
Selective elimination of corticogeniculate feedback abolishes the electroencephalogram dependence of primary visual cortical receptive fields and reduces their spatial specificity
J. Neurosci , 2003
@article{eydingmacklisneubacher2003, title: {Selective elimination of corticogeniculate feedback abolishes the electroencephalogram dependence of primary visual cortical receptive fields and reduces their spatial specificity}, author: {Eyding, D. and Macklis, J D. and Neubacher, U. and Funke, K. and Wörgötter, F.}, year: {2003}, booktitle: {}, journal: {J. Neurosci}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Symbolic Pointillism: Computer art motivated by human perception
Proceedings of the AISB 2003 Symposium on Biologically inspired and Machine Vision, Theory and Application, Wales, 2003
@inproceedings{kruegerwoergoetter2003, title: {Symbolic Pointillism: Computer art motivated by human perception}, author: {Krüger, N. and Wörgötter, F.}, year: {2003}, booktitle: {Proceedings of the AISB 2003 Symposium on Biologically inspired and Machine Vision, Theory and Application, Wales}, journal: {}, }
abstract
bibtex
Rollon, E. and Isern, D. and Agostini, A. and Cortes, U.
Towards the distributed management of emergencies: forest fires case study
Proceeding of the 1st IJCAI Workshop on Environmental Decision Support Systems. Acapulco, Mexico., 2003
@conference{rollonisernagostini2003, title: {Towards the distributed management of emergencies: forest fires case study}, author: {Rollon, E. and Isern, D. and Agostini, A. and Cortes, U.}, year: {2003}, booktitle: {Proceeding of the 1st IJCAI Workshop on Environmental Decision Support Systems. Acapulco, Mexico.}, journal: {}, }

2002

abstract
bibtex
Porr, B. and Nürenberg, B. and Wörgötter, F.
A VLSI-Compatible Computer Vision Algorithm for Stereoscopic Depth analysis in Real-Time
Int. J. Comp. Vis. IJCV , 2002
@article{porrnuerenbergwoergoetter2002, title: {A VLSI-Compatible Computer Vision Algorithm for Stereoscopic Depth analysis in Real-Time}, author: {Porr, B. and Nürenberg, B. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {Int. J. Comp. Vis. IJCV}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Different Degree of Genetical Prestructuring in the Ontogenesis of Visual Abilities based on Deterministic and Statistical Regularities
SAB, Edinburgh, 2002
@inproceedings{kruegerwoergoetter2002e, title: {Different Degree of Genetical Prestructuring in the Ontogenesis of Visual Abilities based on Deterministic and Statistical Regularities}, author: {Krüger, N. and Wörgötter, F.}, year: {2002}, booktitle: {SAB, Edinburgh}, journal: {}, }
abstract
bibtex
Dahlem, M. and Wörgötter, F.
Dynamical retino-cortical mapping
Workshop on Dynamic Perception, Bochum, 2002
@inproceedings{dahlemwoergoetter2002, title: {Dynamical retino-cortical mapping}, author: {Dahlem, M. and Wörgötter, F.}, year: {2002}, booktitle: {Workshop on Dynamic Perception, Bochum}, journal: {}, }
abstract
bibtex
Funke, K. and Kisvarday, Z. and Volgushev, M. and Wörgötter, F.
Integrating anatomy and physiology of the primary visual pathway: from LGN to Cortex
Models of Neural Networks IV, 2002
This chapter deals with the structure and function of the visual thalamus (lateral geniculate nucleus, LGN) and the primary visual cortex and aims to put this system into a computational perspective. We start with an overview of the basic structures of the primary visual pathway and the terminology used. Next, the organization of the LGN and its main functions are described: receptive field structure of LGN cells, excitatory and inhibitory influences, contrast gain- control, spatial summation, temporal structure of activity and influence of extra-retinal inputs. The section closes with models on three functional aspects of the LGN: 1) Switching between burst firing and tonic transmission modes of LGN cells, 2) Control of LGN function during the sleep-wake cycle, and 3) Involvement of LGN in gating visual signals. The section on the visual cortex starts with details of its morphological organisation: cortical layers, cell types, columnar structure and horizontal connections. This is followed by a description of the basic response characteristics of neurons, the organisation of receptive fields and their dynamic behavior. Here, mechanisms of establishing cortical orientation selectivity are considered in detail. Next, we focus on functional maps, e.g. distribution of orientation preferences of cells. The chapter closes with a section on basic models of the primary visual cortex, concerning: 1) Temporal firing patterns of neuronal assemblies, i.e. oscillations and synchronization, 2) Cortical cell characteristics, e.g. orientation specificity, and 3) Formation of functional maps, e.g. orientation map.
@inproceedings{funkekisvardayvolgushev2002, title: {Integrating anatomy and physiology of the primary visual pathway: from LGN to Cortex}, author: {Funke, K. and Kisvarday, Z. and Volgushev, M. and Wörgötter, F.}, year: {2002}, booktitle: {Models of Neural Networks IV}, journal: {}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Isotropic sequence order learning using a novel linear algorithm in a closed loop behavioural system
BioSystems , 2002
@article{porrwoergoetter2002, title: {Isotropic sequence order learning using a novel linear algorithm in a closed loop behavioural system}, author: {Porr, B. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {BioSystems}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Multi-Modal Statistics of Edges in Natural Image Sequences
Proc. WS on Dynamic Perception, Bochum , 2002
In this work we investigate the multi-modal statistics of natural image sequences looking at the modalities orientation, color, optic flow and contrast transition. It turns out the statistical interdependencies corresponding to the Gestalt law collinearity increase significantly when we look not at orientation only.
@misc{kruegerwoergoetter2002, title: {Multi-Modal Statistics of Edges in Natural Image Sequences}, author: {Krüger, N. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {Proc. WS on Dynamic Perception, Bochum}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Multi-modal estimation of collinarity and parallelism in natural image sequences
Network: Comput. Neural Syst , 2002
@article{kruegerwoergoetter2002d, title: {Multi-modal estimation of collinarity and parallelism in natural image sequences}, author: {Krüger, N. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {Network: Comput. Neural Syst}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Multi-modal feature statistics and self-emergence of feature constellations
Workshop on Dynamic Perception, Bochum, 2002
In this work we investigate the multi-modal statistics of natural image sequences looking at the modalities orientation, color, optic flow and contrast transition. It turns out the statistical interdependencies corresponding to the Gestalt low collinearity increases significantly when we look not at orientation only.
@inproceedings{kruegerwoergoetter2002a, title: {Multi-modal feature statistics and self-emergence of feature constellations}, author: {Krüger, N. and Wörgötter, F.}, year: {2002}, booktitle: {Workshop on Dynamic Perception, Bochum}, journal: {}, }
abstract
bibtex
Agostini, A.
Multiagent System for an Intelligent Domiciliary Monitoring of Patients with Cardiovascular Pathologies (in Spanish)
Open Discussion Track Proceedings of the VIII Iberoamerican Conference on Artificial Intelligence (Seville, Spain), 2002
Actualmente existe un considerable numero de personas con enfermedades cardiovasculares que sufren complicaciones en ambitos donde el auxilio medico puede llegar demasiado tarde. Por otro lado la medicina cardiologica ha incorporado recientemente herramientas diagnosticas y pronosticas potentes y no invasivas basadas en el procesamiento de senales obtenidas del sistema cardiovascular utilizando herramientas matematicas avanzadas. El presente trabajo propone un sistema multiagente que vincula estas herramientas y tecnicas de inteligencia artificial, para realizar el monitoreo inteligente de pacientes con patologias cardiovasculares como asi tambien para coordinar las acciones y gestionar los recursos de las tres partes fundamentales que deben intervenir en caso de una emergencia, a saber, el propio paciente y su familia, su medico de cabecera y la institucion de salud respectiva. Se utilizan sistemas de razonamiento basado en casos y basado de reglas para decidir el accionar de acuerdo a la situacion de cada paciente.
@inproceedings{agostini2002, title: {Multiagent System for an Intelligent Domiciliary Monitoring of Patients with Cardiovascular Pathologies (in Spanish)}, author: {Agostini, A.}, year: {2002}, booktitle: {Open Discussion Track Proceedings of the VIII Iberoamerican Conference on Artificial Intelligence (Seville, Spain)}, journal: {}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Predictive learning in rate-coded neural networks: A theoretical approach towards classical conditioning
Neurocomputing , 2002
@article{porrwoergoetter2002a, title: {Predictive learning in rate-coded neural networks: A theoretical approach towards classical conditioning}, author: {Porr, B. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {Neurocomputing}, }
abstract
bibtex
Dahlem, M. and Wörgötter, F.
Rotation-invariant optical flow by gaze-depending retino-cortical mapping
Lecture Notes in Comp. Sci , 2002
@article{dahlemwoergoetter2002a, title: {Rotation-invariant optical flow by gaze-depending retino-cortical mapping}, author: {Dahlem, M. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {Lecture Notes in Comp. Sci}, }
abstract
bibtex
Suder, K. and Funke, K. and Zhao, Y. and Kerscher, N. and Eysel, U. and Wennekers, T. and Wörgötter, F.
Spatial dynamics of receptive fields in cat primary visual cortex related to the temporal structure of thalamo-cortical feed-forward activity experiments and models
Exp. Brain Res , 2002
@article{suderfunkezhao2002, title: {Spatial dynamics of receptive fields in cat primary visual cortex related to the temporal structure of thalamo-cortical feed-forward activity experiments and models}, author: {Suder, K. and Funke, K. and Zhao, Y. and Kerscher, N. and Eysel, U. and Wennekers, T. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {Exp. Brain Res}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
Statistics of second order multi-modal feature events and their exploitation in biological and artificial visual systems
Workshop on Biological Motivated Computer Vision, BMCV, Tübingen, 2002
@inproceedings{kruegerwoergoetter2002b, title: {Statistics of second order multi-modal feature events and their exploitation in biological and artificial visual systems}, author: {Krüger, N. and Wörgötter, F.}, year: {2002}, booktitle: {Workshop on Biological Motivated Computer Vision, BMCV, Tübingen}, journal: {}, }
abstract
bibtex
Hennig, M H. and Kerscher, N J. and Funke, K. and Wörgötter, F.
Stochastic resonance in visual cortical neurons: Does the eye-tremor actually improve visual acuity
Neurocomputing , 2002
@article{hennigkerscherfunke2002, title: {Stochastic resonance in visual cortical neurons: Does the eye-tremor actually improve visual acuity}, author: {Hennig, M H. and Kerscher, N J. and Funke, K. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {Neurocomputing}, }
abstract
bibtex
Krüger, N. and Wörgötter, F.
The Gestalt principle collinearity and the multi-modal statistics of image sequences
Workshop on Cognitive Vision, DAGM, Zürich, 2002
@inproceedings{kruegerwoergoetter2002c, title: {The Gestalt principle collinearity and the multi-modal statistics of image sequences}, author: {Krüger, N. and Wörgötter, F.}, year: {2002}, booktitle: {Workshop on Cognitive Vision, DAGM, Zürich}, journal: {}, }
abstract
bibtex
Hennig, M. and Funke, K. and Wörgötter, F.
The influence of different retinal sub-circuits on the non-linearity of ganglion cell behavior
J. Neurosci , 2002
@article{hennigfunkewoergoetter2002, title: {The influence of different retinal sub-circuits on the non-linearity of ganglion cell behavior}, author: {Hennig, M. and Funke, K. and Wörgötter, F.}, year: {2002}, booktitle: {}, journal: {J. Neurosci}, }
abstract
bibtex
Wörgötter, F. and Eyding, D. and Macklis, J D. and Funke, K.
The influence of the corticothalamic projection on responses in thalamus and cortex
Phil. Trans. R. Soc. Lond. B , 2002
@article{woergoettereydingmacklis2002, title: {The influence of the corticothalamic projection on responses in thalamus and cortex}, author: {Wörgötter, F. and Eyding, D. and Macklis, J D. and Funke, K.}, year: {2002}, booktitle: {}, journal: {Phil. Trans. R. Soc. Lond. B}, }

2001

abstract
bibtex
Wörgötter, F.
Bad design and good performance: Strategies of the visual system for enhanced image analysis
In Proc. Artificial Neural Networks, ICANN 2001 Vienna Dorffner, Bischof and Hornick, eds., Springer, 2001
@inproceedings{woergoetter2001, title: {Bad design and good performance: Strategies of the visual system for enhanced image analysis}, author: {Wörgötter, F.}, year: {2001}, booktitle: {In Proc. Artificial Neural Networks, ICANN 2001 Vienna Dorffner, Bischof and Hornick, eds., Springer}, journal: {}, }
abstract
bibtex
Cozzi, A. and Wörgötter, F.
COMVIS, a communication framework for computer vision
Int. J. Comp. Vis. IJCV , 2001
@article{cozziwoergoetter2001, title: {COMVIS, a communication framework for computer vision}, author: {Cozzi, A. and Wörgötter, F.}, year: {2001}, booktitle: {}, journal: {Int. J. Comp. Vis. IJCV}, }
abstract
bibtex
Suder, K. and Wörgötter, F.
Modeling motion induction to analyze connectivity in the early visual system
Neurocomputing , 2001
@article{suderwoergoetter2001, title: {Modeling motion induction to analyze connectivity in the early visual system}, author: {Suder, K. and Wörgötter, F.}, year: {2001}, booktitle: {}, journal: {Neurocomputing}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
Temporal hebbian learning in rate-coded neural networks: A theoretical approach towards classical conditioning
Proc. Artificial Neural Networks, ICANN 2001 Vienna Dorffner, Bischof and Hornick, eds., Springer, 2001
@inproceedings{porrwoergoetter2001, title: {Temporal hebbian learning in rate-coded neural networks: A theoretical approach towards classical conditioning}, author: {Porr, B. and Wörgötter, F.}, year: {2001}, booktitle: {Proc. Artificial Neural Networks, ICANN 2001 Vienna Dorffner, Bischof and Hornick, eds., Springer}, journal: {}, }

2000

abstract
bibtex
Agostini, A. and Gamero, L. and Rumi, P.
Clinical Application of the Matlab Toolbox VFCLab for the Analysis of the Heart Rate Variability (in Spanish)
Proceeding of the XVII Brazilian Conference in Biomedical Engineering, 2000
La medicina cardiologica ha incorporado recientemente herramientas diagnosticas potentes y no invasivas basadas en el procesamiento de senales obtenidas del sistema cardiovascular. La variabilidad de la frecuencia cardiaca (VFC) es una de ellas y posee informacion muy valiosa referida a patologias cardiovasculares, al estado del sistema nervioso autonomo y al pronostico de la muerte subita cardiaca. En este trabajo se presenta una aplicacion clinica de una biblioteca de funciones desarrolladas con Matlab (Matlab Toolbox) para el analisis matematico de la VFC. Las funciones de dicha biblioteca contienen herramientas para el analisis en el dominio temporal y frecuencial, como asi tambien, herramientas para el estudio de las dinamicas no lineales del sistema cardiovascular. Para la aplicacion clinica se utiliza un grupo de pacientes con patologias cardiovasculares caracteristicas. Se comparan los resultados obtenidos con aquellos de otros trabajos y se presentan los mismos en forma numerica y grafica.
@inproceedings{agostinigamerorumi2000, title: {Clinical Application of the Matlab Toolbox VFCLab for the Analysis of the Heart Rate Variability (in Spanish)}, author: {Agostini, A. and Gamero, L. and Rumi, P.}, year: {2000}, booktitle: {Proceeding of the XVII Brazilian Conference in Biomedical Engineering}, journal: {}, }
abstract
bibtex
Ferber, C. and Wörgötter, F.
Cluster update algorithm and recognition
Phys. Rev. B rapid comm. Phys. Rev. E 62 , 2000
@article{ferberwoergoetter2000, title: {Cluster update algorithm and recognition}, author: {Ferber, C. and Wörgötter, F.}, year: {2000}, booktitle: {}, journal: {Phys. Rev. B rapid comm. Phys. Rev. E 62}, }
abstract
bibtex
Quill, U. and Funke, K. and Wörgötter, F.
Investigations on emergent spatio-temporal neural response characteristics in a small network model
Biol. Cybern , 2000
@article{quillfunkewoergoetter2000, title: {Investigations on emergent spatio-temporal neural response characteristics in a small network model}, author: {Quill, U. and Funke, K. and Wörgötter, F.}, year: {2000}, booktitle: {}, journal: {Biol. Cybern}, }
abstract
bibtex
Suder, K. and Wennekers, T. and Wörgötter, F.
Neural field model of receptive field restructuring in primary visual cortex
Neural Comp , 2000
@article{suderwennekerswoergoetter2000, title: {Neural field model of receptive field restructuring in primary visual cortex}, author: {Suder, K. and Wennekers, T. and Wörgötter, F.}, year: {2000}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Wörgötter, F.
Stereoscopic depth analysis in video real-time based on visual cortical cell behavior and an FPGA solution
Proc. NC2000, Second International ICSC Symposium on Neural Computation Berlin, H.H. Bothe, ed. CD publication only, 2000
@inproceedings{woergoetter2000, title: {Stereoscopic depth analysis in video real-time based on visual cortical cell behavior and an FPGA solution}, author: {Wörgötter, F.}, year: {2000}, booktitle: {Proc. NC2000, Second International ICSC Symposium on Neural Computation Berlin, H.H. Bothe, ed. CD publication only}, journal: {}, }
abstract
bibtex
Suder, K. and Wörgötter, F.
The control of low level information flow in the visual system
Rev. Neurosci , 2000
@article{suderwoergoetter2000, title: {The control of low level information flow in the visual system}, author: {Suder, K. and Wörgötter, F.}, year: {2000}, booktitle: {}, journal: {Rev. Neurosci}, }
abstract
bibtex
Wörgötter, F. and Eysel, U T.
The effects of context and state on receptive fields in the striate cortex
TINS , 2000
@article{woergoettereysel2000, title: {The effects of context and state on receptive fields in the striate cortex}, author: {Wörgötter, F. and Eysel, U T.}, year: {2000}, booktitle: {}, journal: {TINS}, }

1999

abstract
bibtex
Wörgötter, F. and Cozzi, A. and Gerdes, V.
A parallel noise-robust algorithm to recover depth information from radial flow fields
Neural Comp , 1999
@article{woergoettercozzigerdes1999, title: {A parallel noise-robust algorithm to recover depth information from radial flow fields}, author: {Wörgötter, F. and Cozzi, A. and Gerdes, V.}, year: {1999}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Wörgötter, F.
Comparing different modeling approaches of visual cortical cell characteristics
Models of Cortical Circuits, Cerebral Cortex, 1999
The goal of a modeling study should be to arrive at a better analytical and intuitive understanding of the underlying system. To achieve this, every model needs to represent an abstract reflection of reality, and the level of abstraction largely depends on the complexity of the system which is to be modeled. As soon as this complexity exceeds a certain degree, a multitude of possible model levels can be designed and these models can coexist without mutually contradicting each other. A hopeful assumption at this point would be to believe that this diversity could be reduced if all models were required to represent only one common aspect of the system. The complexity of the visual cortex of vertebrates, however, thwarts this hope, because even a single aspect of cortical cell behavior can lead to quite different successful modeling approaches. In this chapter visual cortical orientation specificity shall be the common aspect on which a comparison of different models will be based. The goal shall be to try to develop cross-links between quite different approaches in order to arrive at a
@inproceedings{woergoetter1999, title: {Comparing different modeling approaches of visual cortical cell characteristics}, author: {Wörgötter, F.}, year: {1999}, booktitle: {Models of Cortical Circuits, Cerebral Cortex}, journal: {}, }
abstract
bibtex
Cozzi, A. and Wörgötter, F.
Computing stereoscopic disparity with binocular cortical simple and complex cells
Proc. ICANN99 Edinburgh, 1999
@inproceedings{cozziwoergoetter1999, title: {Computing stereoscopic disparity with binocular cortical simple and complex cells}, author: {Cozzi, A. and Wörgötter, F.}, year: {1999}, booktitle: {Proc. ICANN99 Edinburgh}, journal: {}, }
abstract
bibtex
Li, B. and Funke, K. and Wörgötter, F. and Eysel, U T.
Correlated variations in EEG pattern and visual responsiveness of cat lateral geniculate relay cells
J. Physiol , 1999
@article{lifunkewoergoetter1999, title: {Correlated variations in EEG pattern and visual responsiveness of cat lateral geniculate relay cells}, author: {Li, B. and Funke, K. and Wörgötter, F. and Eysel, U T.}, year: {1999}, booktitle: {}, journal: {J. Physiol}, }
abstract
bibtex
Suder, K. and Wenneckers, T. and Wörgötter, F.
Neural Field description of state-dependent receptive field changes in the visual cortex
Proc. ESANN99, M. Verleysen, ed, 1999
@inproceedings{suderwenneckerswoergoetter1999, title: {Neural Field description of state-dependent receptive field changes in the visual cortex}, author: {Suder, K. and Wenneckers, T. and Wörgötter, F.}, year: {1999}, booktitle: {Proc. ESANN99, M. Verleysen, ed}, journal: {}, }
abstract
bibtex
Suder, K. and Wörgötter, F. and Wenneckers, T.
Neural field description suggests feedforward mechanism of state-dependent visual receptive field changes
Proc. ICANN99, Edinburgh, 1999
@inproceedings{suderwoergoetterwenneckers1999, title: {Neural field description suggests feedforward mechanism of state-dependent visual receptive field changes}, author: {Suder, K. and Wörgötter, F. and Wenneckers, T.}, year: {1999}, booktitle: {Proc. ICANN99, Edinburgh}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Suder, K. and Funke, K.
The dynamic spatio-temporal behavior of visual responses in thalamus and cortex
Restor Neurol Neuroscience , 1999
@article{woergoettersuderfunke1999, title: {The dynamic spatio-temporal behavior of visual responses in thalamus and cortex}, author: {Wörgötter, F. and Suder, K. and Funke, K.}, year: {1999}, booktitle: {}, journal: {Restor Neurol Neuroscience}, }
abstract
bibtex
Agostini, A. and Gamero, L. and Rumi, P.
VFCLab: Matlab Toolbox for the Analysis of the Heart Rate Variability (in Spanish)
Proceeding of the XII Argentinean Conference of Bioengineering, 1999
El analisis de la variabilidad de la frecuencia cardiaca (VFC) constituye una de las herramientas mas prometedoras para el estudio y diagnostico de patologias cardiovasculares y del sistema nervioso autonomo, y para el pronostico de la muerte subita cardiaca. En este trabajo se presenta una biblioteca de funciones para analizar la VFC en el dominio temporal y frecuencial, como asi tambien en el estudio de dinamicas no lineales. Se describen las funciones mas importantes y se efectua una aplicacion practica sobre un registro de Holter de 24 horas de un paciente sano. Se presentan los resultados en forma numerica y grafica.
@inproceedings{agostinigamerorumi1999, title: {VFCLab: Matlab Toolbox for the Analysis of the Heart Rate Variability (in Spanish)}, author: {Agostini, A. and Gamero, L. and Rumi, P.}, year: {1999}, booktitle: {Proceeding of the XII Argentinean Conference of Bioengineering}, journal: {}, }

1998

abstract
bibtex
Opara, R. and Wörgötter, F.
A fast and robust cluster update algorithm for image segmentation in spin-lattice models without annealing visual latencies revisited
Neural Comp , 1998
@article{oparawoergoetter1998, title: {A fast and robust cluster update algorithm for image segmentation in spin-lattice models without annealing visual latencies revisited}, author: {Opara, R. and Wörgötter, F.}, year: {1998}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Wörgötter, F. and Nelle, E. and Li, B. and Wang, L. and Diao, Y.
A possible basic cortical microcircuit called cascaded inhibition Results from cortical network models and recording experiments from striate simple cells
Experimental Brain Research , 1998
@article{woergoetternelleli1998, title: {A possible basic cortical microcircuit called cascaded inhibition Results from cortical network models and recording experiments from striate simple cells}, author: {Wörgötter, F. and Nelle, E. and Li, B. and Wang, L. and Diao, Y.}, year: {1998}, booktitle: {}, journal: {Experimental Brain Research}, }
abstract
bibtex
Köhn, J. and Wörgötter, F.
Employing the Z-Transform to optimize the calculation of the synaptic conductance of NMDA- and other channels in network simulations
Neural Comp , 1998
@article{koehnwoergoetter1998, title: {Employing the Z-Transform to optimize the calculation of the synaptic conductance of NMDA- and other channels in network simulations}, author: {Köhn, J. and Wörgötter, F.}, year: {1998}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Porr, B. and Wörgötter, F.
How to hear visual disparities: Real-time stereoscopic spatial depth analysis using temporal resonance
Biol. Cybern , 1998
@article{porrwoergoetter1998, title: {How to hear visual disparities: Real-time stereoscopic spatial depth analysis using temporal resonance}, author: {Porr, B. and Wörgötter, F.}, year: {1998}, booktitle: {}, journal: {Biol. Cybern}, }
abstract
bibtex
Wörgötter, F. and Nelle, E. and Li, B. and Wang, L. and Diao, Y. -.
Linearity of spatial summation in simple cells: Experiments and Models
Experimental Brain Research , 1998
@article{woergoetternelleli1998a, title: {Linearity of spatial summation in simple cells: Experiments and Models}, author: {Wörgötter, F. and Nelle, E. and Li, B. and Wang, L. and Diao, Y. -.}, year: {1998}, booktitle: {}, journal: {Experimental Brain Research}, }
abstract
bibtex
Cozzi, A. and Wörgötter, F.
Reclustering techniques improve early vision feature maps
Patt. Anal. Appl, 1998
@inproceedings{cozziwoergoetter1998, title: {Reclustering techniques improve early vision feature maps}, author: {Cozzi, A. and Wörgötter, F.}, year: {1998}, booktitle: {Patt. Anal. Appl}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Suder, K. and Zhao, Y. and Kerscher, N. and Eysel, U. and Funke, K.
State-dependent receptive field restructuring in the visual cortex
Nature , 1998
@article{woergoettersuderzhao1998, title: {State-dependent receptive field restructuring in the visual cortex}, author: {Wörgötter, F. and Suder, K. and Zhao, Y. and Kerscher, N. and Eysel, U. and Funke, K.}, year: {1998}, booktitle: {}, journal: {Nature}, }
abstract
bibtex
Suder, K. and Funke, K. and Wörgötter, F.
State-dependent spatio-temporal restructuring of receptive fields in the primary visual pathway
ICANN 98, 1998
Changing patterns in the EEG reflect changing states of attentiveness and are correlated to changes in the firing behavior of single cells. Prom experiments it is known that LGN cells of the Thalamus exhibit a tonic firing pattern during desynchronized EEG reflecting faithfully properties of a stimulus whereas they are in a burst mode during synchronized EEG, which leads to a stereotype stimulus response. We introduce a model in which these changes in the neural temporal behavior lead to changes in the spatial characteristics of cortical receptive fields through variations in the effective connectivity between thalamic and cortical cells. This spatio-temporal receptive field restructuring reflects different modes of information processing and might be controlled by selective attention.
@inproceedings{suderfunkewoergoetter1998, title: {State-dependent spatio-temporal restructuring of receptive fields in the primary visual pathway}, author: {Suder, K. and Funke, K. and Wörgötter, F.}, year: {1998}, booktitle: {ICANN 98}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Nelle, E. and Li, B. and Funke, K.
The influence of corticofugal feedback on the temporal structure of visual responses of cat thalamic relay cells
J. Physiol , 1998
@article{woergoetternelleli1998b, title: {The influence of corticofugal feedback on the temporal structure of visual responses of cat thalamic relay cells}, author: {Wörgötter, F. and Nelle, E. and Li, B. and Funke, K.}, year: {1998}, booktitle: {}, journal: {J. Physiol}, }
abstract
bibtex
Quill, U. and Wörgötter, F. and Funke, K. and Lansner, A.
The role of spatio-temporal structures in the formation of synchrony
ICANN 98, 1998
Although the functional role synchronous oscillations may play has been investigated in depth, the underlying processes and spatio-temporal aspects that establish the synchrony are still not thoroughly understood. Experimental studies suggest the existence of two kinds of oscillations: stimulus-locked and stimulus-induced. While stimulus-locked oscillations are systematically dependent on the stimulus, stimulus-induced oscillations (occurring in the frequency range) show only little stimulus dependency. We propose a unifying approach which employs very generic connection structures. Different degrees of synchrony on different time scales are observed as an emergent feature of the network structure. Our model demonstrates that both, stimulus-locked and stimulus-induced oscillations are just two different states of the same system. A transition from one state to the other is observed, and the synchronous activity provides the basis for binding visual features.
@inproceedings{quillwoergoetterfunke1998, title: {The role of spatio-temporal structures in the formation of synchrony}, author: {Quill, U. and Wörgötter, F. and Funke, K. and Lansner, A.}, year: {1998}, booktitle: {ICANN 98}, journal: {}, }

1997

abstract
bibtex
Opara, R. and Wörgötter, F.
Introducing Visual Latencies into Spin-Lattice Models for Image Segmentation: A Neuromorphic Approach to a Computer Vision Problem
ICNN97 Houston, Texas, 1997
@inproceedings{oparawoergoetter1997, title: {Introducing Visual Latencies into Spin-Lattice Models for Image Segmentation: A Neuromorphic Approach to a Computer Vision Problem}, author: {Opara, R. and Wörgötter, F.}, year: {1997}, booktitle: {ICNN97 Houston, Texas}, journal: {}, }
abstract
bibtex
Funke, K. and Wörgötter, F.
On the significance of temporally structured activity in the dorsal lateral geniculate nucleus LGN
Progress in Neurobiology , 1997
@article{funkewoergoetter1997a, title: {On the significance of temporally structured activity in the dorsal lateral geniculate nucleus LGN}, author: {Funke, K. and Wörgötter, F.}, year: {1997}, booktitle: {}, journal: {Progress in Neurobiology}, }
abstract
bibtex
Cozzi, A. and Crespi, B. and Valentinotti, F. and Wörgötter, F.
Performance of phase-based algorithms for disparity estimation
Mach. Vis. Appl , 1997
@article{cozzicrespivalentinotti1997, title: {Performance of phase-based algorithms for disparity estimation}, author: {Cozzi, A. and Crespi, B. and Valentinotti, F. and Wörgötter, F.}, year: {1997}, booktitle: {}, journal: {Mach. Vis. Appl}, }
abstract
bibtex
Funke, K. and Wörgötter, F.
The temporal dynamics of cell responses in the lateral geniculate nucleus
Prog. in Neurobiol , 1997
@article{funkewoergoetter1997, title: {The temporal dynamics of cell responses in the lateral geniculate nucleus}, author: {Funke, K. and Wörgötter, F.}, year: {1997}, booktitle: {}, journal: {Prog. in Neurobiol}, }

1996

abstract
bibtex
Opara, R. and Wörgötter, F.
A novel algorithm for image segmentation using time dependent interaction probabilities
Artificial Neural Networks, 1996
For a consistent analysis of a visual scene the different features of an individual object have to be recognized as belonging together and separated from other objects and the background. Classical algorithms to segment a visual scene have an implicit representation of the image in the connection structure. We propose a new model that uses an image representation in the time domain, operating on stimulus dependent latencies. Such stimulus dependent temporal differences are observed in biological sensory systems. In our system they will be used to define the interaction probability between the different image parts. The gradually changing pattern of active image parts will thereby lead to the assignment of the different labels to different regions which leads to the segmentation of the scene.
@inproceedings{oparawoergoetter1996, title: {A novel algorithm for image segmentation using time dependent interaction probabilities}, author: {Opara, R. and Wörgötter, F.}, year: {1996}, booktitle: {Artificial Neural Networks}, journal: {}, }
abstract
bibtex
Vogelgesang, J. and Cozzi, A. and Wörgötter, F.
A parallel algorithm for depth perception from radial optical flow fields
Lect. Notes in Comp. Sci. and Proc. of ICANN96, C.v.d.Malsburg, W.v.Seelen, J.C. Vorbrüggen, B. Sendhoff, eds., Springer, 1996
@inproceedings{vogelgesangcozziwoergoetter1996, title: {A parallel algorithm for depth perception from radial optical flow fields}, author: {Vogelgesang, J. and Cozzi, A. and Wörgötter, F.}, year: {1996}, booktitle: {Lect. Notes in Comp. Sci. and Proc. of ICANN96, C.v.d.Malsburg, W.v.Seelen, J.C. Vorbrüggen, B. Sendhoff, eds., Springer}, journal: {}, }
abstract
bibtex
Köhn, J. and Wörgötter, F.
Corticofugal feedback can reduce the visual latency of responses to antagonistic stimuli
Biol. Cybern , 1996
@article{koehnwoergoetter1996, title: {Corticofugal feedback can reduce the visual latency of responses to antagonistic stimuli}, author: {Köhn, J. and Wörgötter, F.}, year: {1996}, booktitle: {}, journal: {Biol. Cybern}, }
abstract
bibtex
Funke, K. and Nelle, E. and Li, B. and Wörgötter, F.
Corticofugal feedback improves the timing of retino-geniculate signal transmission
NeuroReport , 1996
@article{funkenelleli1996, title: {Corticofugal feedback improves the timing of retino-geniculate signal transmission}, author: {Funke, K. and Nelle, E. and Li, B. and Wörgötter, F.}, year: {1996}, booktitle: {}, journal: {NeuroReport}, }
abstract
bibtex
Opara, R. and Wörgötter, F.
Utilizing latency for object recognition in artificial neural networks
Neural Comp , 1996
@article{oparawoergoetter1996a, title: {Utilizing latency for object recognition in artificial neural networks}, author: {Opara, R. and Wörgötter, F.}, year: {1996}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Wörgötter, F. and Opara, R. and Funke, K. and Eysel, T.
Utilizing latency for object recognition in real and artificial neural networks
NeuroReport , 1996
@article{woergoetteroparafunke1996, title: {Utilizing latency for object recognition in real and artificial neural networks}, author: {Wörgötter, F. and Opara, R. and Funke, K. and Eysel, T.}, year: {1996}, booktitle: {}, journal: {NeuroReport}, }

1995

abstract
bibtex
Funke, K. and Wörgötter, F.
Differences in the temporal dynamics of the visual ON- and OFF-pathways
Exp. Brain Res , 1995
@article{funkewoergoetter1995a, title: {Differences in the temporal dynamics of the visual ON- and OFF-pathways}, author: {Funke, K. and Wörgötter, F.}, year: {1995}, booktitle: {}, journal: {Exp. Brain Res}, }
abstract
bibtex
Wörgötter, F. and Funke, K.
Fine structure analysis of temporal patterns in the light response of cells in the lateral geniculate nucleus of cat
Visual Neurosci , 1995
@article{woergoetterfunke1995, title: {Fine structure analysis of temporal patterns in the light response of cells in the lateral geniculate nucleus of cat}, author: {Wörgötter, F. and Funke, K.}, year: {1995}, booktitle: {}, journal: {Visual Neurosci}, }
abstract
bibtex
Opara, R. and Wörgötter, F.
Improving object recognition by using a visual latency mechanism
Europ. Symp. Artif. Neural Networks M. Verleysen, ed. D-Facto, Brussels, 1995
@inproceedings{oparawoergoetter1995, title: {Improving object recognition by using a visual latency mechanism}, author: {Opara, R. and Wörgötter, F.}, year: {1995}, booktitle: {Europ. Symp. Artif. Neural Networks M. Verleysen, ed. D-Facto, Brussels}, journal: {}, }
abstract
bibtex
Köhn, J. and Wörgötter, F.
Latency-reduction in antagonistic visual channels as the result of corticofugal feedback
Europ. Symp. Artif. Neural Networks M. Verleysen, ed, 1995
@inproceedings{koehnwoergoetter1995, title: {Latency-reduction in antagonistic visual channels as the result of corticofugal feedback}, author: {Köhn, J. and Wörgötter, F.}, year: {1995}, booktitle: {Europ. Symp. Artif. Neural Networks M. Verleysen, ed}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Nelle, E. and Li, B. and Wang, L. and Diao, Y-C.
Spatial summation in simple cells: Computational and experimental results
Europ. Symp. Artif. Neural Networks M. Verleysen, ed. D-Facto, Brussels, 1995
@inproceedings{woergoetternelleli1995, title: {Spatial summation in simple cells: Computational and experimental results}, author: {Wörgötter, F. and Nelle, E. and Li, B. and Wang, L. and Diao, Y-C.}, year: {1995}, booktitle: {Europ. Symp. Artif. Neural Networks M. Verleysen, ed. D-Facto, Brussels}, journal: {}, }
abstract
bibtex
Funke, K. and Wörgötter, F.
Temporal structure in the light response of relay cells in the dorsal lateral geniculate nucleus of cat
J. Physiol. Lond , 1995
@article{funkewoergoetter1995, title: {Temporal structure in the light response of relay cells in the dorsal lateral geniculate nucleus of cat}, author: {Funke, K. and Wörgötter, F.}, year: {1995}, booktitle: {}, journal: {J. Physiol. Lond}, }

1994

abstract
bibtex
Opara, R. and Wörgötter, F.
A Multi-Modular hardware-software development for visual scene analysis
Proc. of CNS94, Monterey, California, 1994
@inproceedings{oparawoergoetter1994, title: {A Multi-Modular hardware-software development for visual scene analysis}, author: {Opara, R. and Wörgötter, F.}, year: {1994}, booktitle: {Proc. of CNS94, Monterey, California}, journal: {}, }
abstract
bibtex
Niebur, E. and Wörgötter, F.
Design principles of columnar organization in visual cortex
Neural Comp , 1994
@article{nieburwoergoetter1994, title: {Design principles of columnar organization in visual cortex}, author: {Niebur, E. and Wörgötter, F.}, year: {1994}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Eysel, U. and Kisvarday, Z F. and Wörgötter, F. and Crook, J.
Large basket cells and lateral inhibition in cat visual cortex
Springer, Heidelberg Structural and Functional Organization of the Neocortex. Experimental Brain Research Series 24, 1994
@inproceedings{eyselkisvardaywoergoetter1994, title: {Large basket cells and lateral inhibition in cat visual cortex}, author: {Eysel, U. and Kisvarday, Z F. and Wörgötter, F. and Crook, J.}, year: {1994}, booktitle: {Structural and Functional Organization of the Neocortex. Experimental Brain Research Series 24}, journal: {Springer, Heidelberg}, }
abstract
bibtex
Crook, J. and Wörgötter, F. and Eysel, U.
Velocity invariance of preferred axis of motion for single spot stimuli in simple cells of cat striate cortex
Exp. Brain Res , 1994
@article{crookwoergoettereysel1994, title: {Velocity invariance of preferred axis of motion for single spot stimuli in simple cells of cat striate cortex}, author: {Crook, J. and Wörgötter, F. and Eysel, U.}, year: {1994}, booktitle: {}, journal: {Exp. Brain Res}, }

1993

abstract
bibtex
Nelle, E. and Wörgötter, F.
Cascaded intracortical inhibition: Modelling connection schemes on a large scale simulator
ICANN 93, Proc. Int. Conf. Artificial Neural Networks, Amsterdam, 1993
@inproceedings{nellewoergoetter1993, title: {Cascaded intracortical inhibition: Modelling connection schemes on a large scale simulator}, author: {Nelle, E. and Wörgötter, F.}, year: {1993}, booktitle: {ICANN 93, Proc. Int. Conf. Artificial Neural Networks, Amsterdam}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Niebur, E.
Cortical column design: A link between the maps of preferred orientation and orientation tuning strength
Biological Cybernetics , 1993
We demonstrate that the map of the preferred orientations and the corresponding map of the orientation tuning strengths as measured with optical imaging are not independent, but that band-pass filtering of the preferred orientation map at each location yields a good approximation of the orientation tuning strength. Band-pass filtering is performed by convolving the map of orientation preference with its own autocorrelation function. We suggest an interpretation of the autocorrelation function of the preferred orientations as synaptic coupling function, i.e., synaptic strength as a function of intracortical distance between cortical cells. In developmental models it has been shown previously that a
@article{woergoetterniebur1993, title: {Cortical column design: A link between the maps of preferred orientation and orientation tuning strength}, author: {Wörgötter, F. and Niebur, E.}, year: {1993}, booktitle: {}, journal: {Biological Cybernetics}, }
abstract
bibtex
Niebur, E. and Wörgötter, F.
Orientation columns from first principles
Computation and Neural Systems 92. F. Eeckman, Ed., Kluver Academic, 1993
@inproceedings{nieburwoergoetter1993, title: {Orientation columns from first principles}, author: {Niebur, E. and Wörgötter, F.}, year: {1993}, booktitle: {Computation and Neural Systems 92. F. Eeckman, Ed., Kluver Academic}, journal: {}, }

1992

abstract
bibtex
Huck, M. and Wörgötter, F. and Eysel, U T.
A processor ring for the implementation of neural networks with cortical architecture
Artificial Neural Networks 2, I.Aleksander and J.Taylor eds, 1992
@inproceedings{huckwoergoettereysel1992, title: {A processor ring for the implementation of neural networks with cortical architecture}, author: {Huck, M. and Wörgötter, F. and Eysel, U T.}, year: {1992}, booktitle: {Artificial Neural Networks 2, I.Aleksander and J.Taylor eds}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Niebur, E. and Koch, C.
Generation of direction selectivity by isotropic intracortical connections
Neural Comp , 1992
To what extent do the mechanisms generating different receptive field properties of neurons depend on each other? We investigated this question theoretically within the context of orientation and direction tuning of simple cells in the mammalian visual cortex. In our model a cortical cell of the "simple" type receives its orientation tuning by afferent convergence of aligned receptive fields of the lateral geniculate nucleus (Hubel and Wiesel 1962). We sharpen this orientation bias by postulating a special type of radially symmetric long-range lateral inhibition called circular inhibition. Surprisingly, this isotropic mechanism leads to the emergence of a strong bias for the direction of motion of a bar. We show that this directional anisotropy is neither caused by the probabilistic nature of the connections nor is it a consequence of the specific columnar structure chosen but that it is an inherent feature of the architecture of visual cortex.
@article{woergoetternieburkoch1992, title: {Generation of direction selectivity by isotropic intracortical connections}, author: {Wörgötter, F. and Niebur, E. and Koch, C.}, year: {1992}, booktitle: {}, journal: {Neural Comp}, }
abstract
bibtex
Eysel, U T. and Wörgötter, F.
Horizontal intracortical contributions to functional specificity in cat visual cortex
Information Processing in the Cortex. Experiment and Theory. A.Aertsen and V. Braitenberg Hrsg, 1992
Intracortical lateral connections have initially been shown in anatomical studies by degeneration methods in monkey (Fisken et al. 1975) and cat (Creutzfeldt et al. 1977). However, only the use of modern tracer techniques has disclosed details like the periodic spatial pattern of such intracortical connections (Rockland and Lund 1982, 1983 Gilbert and Wiesel 1983 Gilbert 1985) or the axonal and dendritic distribution of single excitatory or inhibitory cells (Gilbert and Wiesel 1979 Somogyi et al. 1983 Kisvarday et al. 1985). Intracortical excitation can be laterally transmitted by a long-range axonal network of excitatory connections between pyramidal cells spanning up to about 5 mm in the adult cat visual cortex (Kisvarday and Eysel 1991 see also the contribution of Kisvarday in this volume). Intracortical inhibition can be mediated by GABAergic cells which comprise on the average 20% of the cortical neurons in rat, cat and monkey (Ribak 1978 Hendrickson et al. 1981 Gabbott and Somogyi 1986 Fitz Patrick et al. 1987 Hendry et al. 1987). These nonpyramidal cells are a heterogenous group which show a variety of morphological specializations (Somogyi 1986). Some of the GABAergic cells give rise to locally restricted axonal systems (Kisvarday et al. 1985), others send axons over distances from 0.5 to 2 mm (Somogyi et al. 1983 Matsubara et al. 1987b).
@inproceedings{eyselwoergoetter1992, title: {Horizontal intracortical contributions to functional specificity in cat visual cortex}, author: {Eysel, U T. and Wörgötter, F.}, year: {1992}, booktitle: {Information Processing in the Cortex. Experiment and Theory. A.Aertsen and V. Braitenberg Hrsg}, journal: {}, }

1991

abstract
bibtex
Wörgötter, F. and Koch, C.
A detailed model of the primary visual pathway in the cat. Comparison of afferent excitatory and intracortical inhibitory connection schemes for orientation selectivity
J. Neurosci , 1991
@article{woergoetterkoch1991, title: {A detailed model of the primary visual pathway in the cat. Comparison of afferent excitatory and intracortical inhibitory connection schemes for orientation selectivity}, author: {Wörgötter, F. and Koch, C.}, year: {1991}, booktitle: {}, journal: {J. Neurosci}, }
abstract
bibtex
Wörgötter, F. and Eysel, U T.
Axial responses in visual cortical cells. Spatio-temporal mechanisms quantified by Fourier components of cortical tuning curves
Exp. Brain Res , 1991
@article{woergoettereysel1991, title: {Axial responses in visual cortical cells. Spatio-temporal mechanisms quantified by Fourier components of cortical tuning curves}, author: {Wörgötter, F. and Eysel, U T.}, year: {1991}, booktitle: {}, journal: {Exp. Brain Res}, }
abstract
bibtex
Wörgötter, F. and Muche, T. and Eysel, U T.
Correlations between directional and orientational tuning of cells in cat striate cortex
Exp. Brain Res , 1991
@article{woergoettermucheeysel1991, title: {Correlations between directional and orientational tuning of cells in cat striate cortex}, author: {Wörgötter, F. and Muche, T. and Eysel, U T.}, year: {1991}, booktitle: {}, journal: {Exp. Brain Res}, }
abstract
bibtex
Niebur, E. and Wörgötter, F. and C., K.
Influence of the column structure on intracortical long-range interactions
Proc. 3rd Mid-Western Conf. on Neural Networks, S. Samir ed., Purdue Univ. Press, W. Lafayett, 1991
@inproceedings{nieburwoergoetterc1991, title: {Influence of the column structure on intracortical long-range interactions}, author: {Niebur, E. and Wörgötter, F. and C., K.}, year: {1991}, booktitle: {Proc. 3rd Mid-Western Conf. on Neural Networks, S. Samir ed., Purdue Univ. Press, W. Lafayett}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Niebur, E. and Koch, C.
Isotropic connections generate functional asymmetrical behavior in visual cortical cells
Journal of Neurophysiology , 1991
We study the relationship between structure and function in inhibitory long-range interactions in visual cortex. The sharpening of orientation tuning with "cross-orientation inhibition" is used as an example to discuss anisotropies that are generated by long-range connections. 2. In this study, as opposed to the detailed cortex model described in a previous report, a model of the cortical orientation column structure is proposed in which cortical cells are described only by their orientation preference. 3. We present results using different geometric arrangements of orientation columns. In the simplest case, straight parallel orientation columns were used. We also utilized more realistic, curved columns generated by a simple algorithm. The results were confirmed by the study of a patch of real column structure, determined experimentally by Swindale et al. 4. A given cell receives functionally defined cross-orientation inhibition if the cell receives inhibitory input that is strongest along its nonpreferred orientation. On the other hand, a cell is said to receive structurally defined cross-orientation inhibition if the inhibition arises from source cells with an orientation preference orthogonal to that of the target cell. Even though those definitions seem to describe similar situations, we show that, in the general case, structurally defined cross-orientation inhibition does not efficiently sharpen orientation selectivity. In particular, for straight and parallel columns, structurally defined cross-orientation inhibition results in unequal amounts of inhibition for whole cell populations with different preferred orientations. 5. In more realistic column structures, we studied the question of whether structural cross-orientation inhibition could be implemented in a more efficient way. However, for the majority of cells, it is demonstrated that their nonpreferred stimulus will not preferably excite "cross-oriented" cells. Thus structural cross-orientation inhibition is not efficient in real cortical columns. 6. We propose a new mechanism called circular inhibition. In this connection scheme, a target cell receives inhibitory input from source cells that are located at a given distance (the same for all cells) from the target cell. Circular inhibition can be regarded as two-dimensional long-range lateral inhibition. As opposed to structural cross-orientation inhibition, this mechanism does not introduce unwanted anisotropies in the orientation tuning of the target cells. It is also conceptually much simpler and developmentally advantageous. It is shown that this connection scheme results in a net functional cross-orientation inhibition in all realistic column geometries. The inhibitory tuning strength obtained with circular inhibition is weak and similar to that measured in reality.
@article{woergoetternieburkoch1991, title: {Isotropic connections generate functional asymmetrical behavior in visual cortical cells}, author: {Wörgötter, F. and Niebur, E. and Koch, C.}, year: {1991}, booktitle: {}, journal: {Journal of Neurophysiology}, }
abstract
bibtex
Wörgötter, F. and Holt, G.
Spatio-temporal mechanisms in receptive fields of visual cortical simple cells: A model
J. Neurophysiol , 1991
@article{woergoetterholt1991, title: {Spatio-temporal mechanisms in receptive fields of visual cortical simple cells: A model}, author: {Wörgötter, F. and Holt, G.}, year: {1991}, booktitle: {}, journal: {J. Neurophysiol}, }
abstract
bibtex
Niebur, E. and Wörgötter, F. and Koch, C.
The Caltech computer cat: A fine-grain simulator of the primary visual system of cat
Annales du Carnac, 1991
@inproceedings{nieburwoergoetterkoch1991, title: {The Caltech computer cat: A fine-grain simulator of the primary visual system of cat}, author: {Niebur, E. and Wörgötter, F. and Koch, C.}, year: {1991}, booktitle: {Annales du Carnac}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Eysel, U.
Topographical aspects of the contributions of intracortical excitation and inhibition to orientation specificity in area 17 of the cat visual cortex. Europ
J. Neurosci , 1991
Intracortical mechanisms contributing to orientation and direction specificity were investigated with a method of local cortical inactivation. Single-unit activity was recorded in area 17 of the anaesthetized cat while a small volume of cortical tissue 400 - 2900 microm lateral to the recorded cell was inactivated by gamma-aminobutyric acid (GABA) microiontophoresis. Cells were stimulated with moving bars of variable orientation and changes of the response were monitored. Recording and inactivation sites were histologically verified. Statistically significant changes in orientation tuning during GABA-induced remote inactivation were observed in 80 of 145 cells (55%), and consisted in a reduced orientation specificity due to either increased (36%) or decreased (19%) responses. Increases of responses were more pronounced for the non-optimal orientations. This effect mainly occurred with GABA application at distances around 500 microm and is interpreted as loss of inhibition. Reduced orientation specificity as a result of decreasing response mainly to the optimal orientation was interpreted as loss of excitation. This effect most frequently occurred with inactivation at distances around 1000 microm. Loss of inhibition was also elicited from a distance of 1000 microm such inhibition, however, affected only directionality, without inducing changes in orientation tuning. For several cells at distances 1000 microm from the inactivation site a temporal sequence consisting of a change in direction specificity followed by a reduction of orientation specificity, and finally by direct GABAergic inhibition of the cell under study, could be induced with gradually increasing ejecting currents. The results indicate that excitation and inhibition originating from populations of neurons at different horizontal distances differentially contribute to direction and orientation specificity of a given visual cortical cell.
@article{woergoettereysel1991a, title: {Topographical aspects of the contributions of intracortical excitation and inhibition to orientation specificity in area 17 of the cat visual cortex. Europ}, author: {Wörgötter, F. and Eysel, U.}, year: {1991}, booktitle: {}, journal: {J. Neurosci}, }

1990

abstract
bibtex
Wörgötter, F. and Niebur, E. and Koch, C.
Modeling visual cortex: Hidden anisotropies in an isotropic inhibitory connection scheme
Advanced Neural Computers, R. Eckmiller ed. Elsevier Amsterdam, 1990
A detailed cortex model (15,000 cells) of the adult cat is presented and it is shown that a combination of unspecific inhibitory mechanisms together with input of aligned receptive fields from the LGN with little elongation (1:1.5) is able to reproduce cortical orientation selectivity and other features of cortical cell behavior. We introduce a novel isotropic intracortical con nection scheme ("cir-cular inhibition") and demonstrate analytically that this mechanism results in two anisotropies: orientation tuning and a directional bias. Thus, our network shows that structurally unspecific isotropic connections can result in functionally specific behavior. Directional anisotropy introduced in this way could be the starting point for the development of the true direction specificity found in cortical cells.
@inproceedings{woergoetternieburkoch1990, title: {Modeling visual cortex: Hidden anisotropies in an isotropic inhibitory connection scheme}, author: {Wörgötter, F. and Niebur, E. and Koch, C.}, year: {1990}, booktitle: {Advanced Neural Computers, R. Eckmiller ed. Elsevier Amsterdam}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Gründel, O. and Eysel, U T.
Quantification and comparison of cell properties in cats striate cortex determined by different types of stimuli
Europ. J. Neurosci , 1990
@article{woergoettergruendeleysel1990, title: {Quantification and comparison of cell properties in cats striate cortex determined by different types of stimuli}, author: {Wörgötter, F. and Gründel, O. and Eysel, U T.}, year: {1990}, booktitle: {}, journal: {Europ. J. Neurosci}, }
abstract
bibtex
Niebur, E. and Wörgötter, F.
Sharpening of orientation selective receptive fields in the mammalian visual cortex by long-range interactions
Proc. of the German Workshop on Artificial Intelligence GWAI-90, 1990
Lateral intracortical interactions are believed to be responsible for the sharpening of the receptive field profiles of visual cortical cells. This study demonstrates a structurally imposed limitation of long range interactions on the frequently invoked cross orientation inhibition scheme: it leads to inhomogeneous input for different cell populations which is experimentally not observed. We propose a novel connection scheme called
@inproceedings{nieburwoergoetter1990, title: {Sharpening of orientation selective receptive fields in the mammalian visual cortex by long-range interactions}, author: {Niebur, E. and Wörgötter, F.}, year: {1990}, booktitle: {Proc. of the German Workshop on Artificial Intelligence GWAI-90}, journal: {}, }
abstract
bibtex
Wörgötter, F. and Kammen, D. M. and Brandt, B.
Temporal dynamics in neuronal microcircuitry
Parallel Processing in Neural Systems and Computers, R. Eckmiller, G. Hartmann and G. Hauske eds, 1990
@inproceedings{woergoetterkammenbrandt1990, title: {Temporal dynamics in neuronal microcircuitry}, author: {Wörgötter, F. and Kammen, D. M. and Brandt, B.}, year: {1990}, booktitle: {Parallel Processing in Neural Systems and Computers, R. Eckmiller, G. Hartmann and G. Hauske eds}, journal: {}, }

1989

abstract
bibtex
Wörgötter, F. and Eysel, U T.
Axis of preferred motion is a function of bar length in visual cortical receptive fields
Exp. Brain Res , 1989
The responses of 82 simple cells and 41 complex cells in area 17 of anesthetized and paralysed cats were examined with light bars of different length. For 84% of the simple cells and 66% of the complex cells the preferred axis of orientation of a stationary flashing long bar (orientational selectivity) and the preferred axis of movement of a small spot were parallel. As a consequence, the axis of maximal response to a moving light spot was mostly orthogonal to the optimal axis of a moving bar. Thus, a single cell responds to two perpendicular axes of preferred movement one for a long bar and one for a light spot, respectively. For both axes independent direction preferences could be distinguished. Additional preferred axes of movement between the two orthogonal extremes could be found with moving bars of intermediate lengths. This can be explained by the fact that cells with a pronounced response to a moving spot showed a strong tendency for intermediate bar length to elicit responses consisting of a superposition of both components. Therefore, decreasing bar length resulted in a gradual rotation of the preferred direction of movement from orthogonal to parallel with respect to the orientational axis, rather than to a mere widening of the tuning curve. Accordingly, the change in orientation selectivity with decreasing bar length is a regular transition from the orientation dependent response to a response type that depends only on the movement axis of the spot. Thus, in a simple model, the resulting response characteristic can be interpreted as an average of both components weighted according to the length of the stimulus.
@article{woergoettereysel1989, title: {Axis of preferred motion is a function of bar length in visual cortical receptive fields}, author: {Wörgötter, F. and Eysel, U T.}, year: {1989}, booktitle: {}, journal: {Exp. Brain Res}, }

1988

abstract
bibtex
Wörgötter, F. and Eysel, U. T.
A simple glass coated, fire-polished tungsten electrode with impedance adjustment using hydrofluoridic acid
Journal of Neuroscience Methods , 1988
A method is described to produce glass-coated tungsten microelectrodes in 4 simple steps: (1) etching of the wire, (2) coating with glass, (3) fire-polishing, and (4) reopening with hydrofluoric acid to adjust the conductance to a final value. Continuous conductance control is provided during the reopening process by means of an admittance meter to guarantee an exact final adjustment of the conductance required. The complete process yields electrodes of high reliability within a few minutes and the quality of the electrodes remains largely unaffected by any of the manufacturing parameters involved, so that high-performance electrodes are produced without sophisticated procedures. The electrodes have been tested successfully over several years recording from cells in the striate visual pathway of the cat.
@article{woergoettereysel1988, title: {A simple glass coated, fire-polished tungsten electrode with impedance adjustment using hydrofluoridic acid}, author: {Wörgötter, F. and Eysel, U. T.}, year: {1988}, booktitle: {}, journal: {Journal of Neuroscience Methods}, }
abstract
bibtex
Eysel, U. T. and Muche, T. and Wörgötter, F.
Lateral interactions at directions-selective striate neurones in the cat demonstrated by local cortical inactivation
The Journal of Physiology , 1988
1. Single neurones were recorded with glass-coated tungsten electrodes from area 17 of the cats visual cortex. The cats were anaesthetized and artificially respirated with a mixture of halothane, nitrous oxide and oxygen. 2. For local cortical inactivation a multibarrel pipette was placed 0.5-2.5 mm posterior (or anterior) to the recording site, at a depth of 400-600 micron. Four separate barrels of the pipette were filled with gamma-aminobutyric acid (GABA) the fifth was filled with Pontamine Sky Blue for labelling of the centre of the inactivation site. 3. Direction-selective cells, of differing optimal orientations and preferred directions of motion, were classified as simple or complex and tested with computer-controlled stimuli presented on an oscilloscope. 4. During continuous recording GABA was microionophoretically applied for different durations and with different ejection currents. The effectiveness of GABA microionophoresis was evident from the direct GABAergic effects (strong overall inhibition of the recorded cells) observed with high ejection currents and prolonged application. 5. Two discrete effects could be observed during local inactivation distant from the cortical cell under study: an increase of the response in either the non-preferred or the preferred direction or a decrease of the response in the preferred direction. All GABA-induced changes were reversible. 6. The depressant action of GABA was independent of the relative topography between recording and inactivation site and affected mainly the response to the preferred direction of stimulus motion. 7. Disinhibition was only observed when the stimulus-evoked response moved on the cortical map in a direction from the GABA pipette towards the recording electrode. It is concluded that GABA reversibly silences inhibitory interneurones that are situated in the vicinity of the micropipette tip and are involved in generation of direction selectivity. 8. No fundamental differences between cells from different cortical layers were observed. The disinhibitory effects of GABA inactivation were more pronounced and more frequently seen in simple cells (61%) than in complex cells (38%), while the opposite was true for reduced excitation during lateral GABA inactivation (observed in 62% of the complex vs. 39% of the simple cells). Accordingly, lateral inhibition statistically prevails in simple cells and lateral excitation in complex cells. 9. Among the inhibitory and excitatory mechanisms affected by lateral GABA inactivation, inhibition is organized with a higher topographic specificity.
@article{eyselmuchewoergoetter1988, title: {Lateral interactions at directions-selective striate neurones in the cat demonstrated by local cortical inactivation}, author: {Eysel, U. T. and Muche, T. and Wörgötter, F.}, year: {1988}, booktitle: {}, journal: {The Journal of Physiology}, }

1987

abstract
bibtex
Eysel, U T. and Wörgötter, F. and Pape, H C.
Local cortical lesions abolish lateral inhibition at direction selective cells in cat visual cortex
Exp. Brain Res , 1987
Many cells in the cat visual cortex display a strong selectivity for the direction of motion of an optimally oriented stimulus. Postsynaptic inhibition has been suggested to generate this direction selectivity in simple cells, but the intracortical pathways involved have not been identified. While continuously recording from simple cells in layers 4 and 6, we have inactivated the superficial cortical layers in small regions 0.4-2.5 mm from the cortical column under study by using heat lesions, localized cooling or -aminobutyric acid (GABA) microiontophoresis. When inactivation affected cortical regions retinotopically representing motion in the non-preferred direction towards the receptive field, the responses to movement in this direction increased, and the recorded cells lost direction selectivity due to loss of inhibition. Our results indicate that direction selectivity of simple cells involves asymmetric inhibition of predictable cortical topography.
@article{eyselwoergoetterpape1987, title: {Local cortical lesions abolish lateral inhibition at direction selective cells in cat visual cortex}, author: {Eysel, U T. and Wörgötter, F. and Pape, H C.}, year: {1987}, booktitle: {}, journal: {Exp. Brain Res}, }
abstract
bibtex
Wörgötter, F. and Eysel, U T.
Quantitative determination of orientational and directional components in the response of visual cortical cells to moving stimuli
Biol. Cybern , 1987
The response characteristic of visual cortical cells to moving oriented stimuli consists mainly of directional (D) and orientational (O) components superimposed to a spontaneous activity (S). Commonly used polar plot diagrams reflect the maximal responses for different orientations and directions of stimulus movement with a periodicity of 360 degrees in the visual field. Fast Fourier analysis (FFT) is applied to polar plot data in order to determine the intermingled S, D, and O components. The zero order gain component of the spectrum corresponds to a (virtual) spontaneous activity. The first order component is interpreted as the strength of the direction selectivity and the second order component as the strength of the orientation specificity. The axes of the preferred direction and optimal orientation are represented by the respective phase values. Experimental data are well described with these parameters and relative changes of the shape of a polar plot can be detected with an accuracy better than 1%. The results are compatible with a model of converging excitatory and inhibitory inputs weighted according to the zero to second order components of the Fourier analysis. The easily performed quantitative determination of the S, D, and O components allows the study of pharmacologically induced changes in the dynamic response characteristics of single visual cortical cells.
@article{woergoettereysel1987, title: {Quantitative determination of orientational and directional components in the response of visual cortical cells to moving stimuli}, author: {Wörgötter, F. and Eysel, U T.}, year: {1987}, booktitle: {}, journal: {Biol. Cybern}, }

1986

abstract
bibtex
Wörgötter, F. and Daunicht, W J. and Eckmiller, R.
An on-line spike form discriminator based on an analog correlation technique
J. Neurosci. Meth , 1986
The discrimination of single unit activity in extracellular recordings presents a serious problem when the signal-to-noise ratio is low or when the amplitudes of interspersed spikes are similar. By exploiting spike form, the system described here performs discrimination using on-line hardware template matching. Using analog delay lines, the combined deviation of 8 input signal values from 8 stored template values is calculated simultaneously. The 8 template values are selected by adjusting 8 cursors to the desired spike trace on a CRT the spike form discriminator (SPIFODIS) then generates a deviation function which steeply drops to zero whenever form similarity occurs, allowing for easy triggering. The performance of SPIFODIS was compared quantitatively with that of a conventional amplitude trigger in two cases: (a) when detecting a single unit with varied signal-to-noise ratios and (b) when separating double units of equal amplitude. (a) At signal-to-noise ratios between 2 and 1 the error rate for SPIFODIS was only 15-50% of that of an amplitude trigger. (b) In double-unit recordings showing only form differences, spikes are discriminated with very low error rate, while an amplitude trigger fails completely.
@article{woergoetterdaunichteckmiller1986, title: {An on-line spike form discriminator based on an analog correlation technique}, author: {Wörgötter, F. and Daunicht, W J. and Eckmiller, R.}, year: {1986}, booktitle: {}, journal: {J. Neurosci. Meth}, }
Computational Neuroscience Group