Geisel, Theo

[["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Kim, Douglas S."],["dc.contributor.author","Bonhoeffer, Tobias"],["dc.contributor.editor","Gielen, S."],["dc.contributor.editor","Kappen, B."],["dc.date.accessioned","2017-09-07T11:46:18Z"],["dc.date.available","2017-09-07T11:46:18Z"],["dc.date.issued","2012"],["dc.description.abstract","We propose a mathematical description for the spatial organization of orientation preference in the visual cortex. In this approach the spatial pattern of orientation preference is predicted from position and chirality of its singularities (i.e. ”pinwheels”). The theory is derived from a few phenomenological principles characterizing the qualitative structure of orientation maps under the requirement of mathematical simplicity. A comparison with optically recorded images of cortical maps suggests that orientation preference can be predicted over a much larger spatial range than previously estimated on the basis of correlation measurements."],["dc.identifier.doi","10.1007/978-1-4471-2063-6_30"],["dc.identifier.gro","3151879"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8711"],["dc.language.iso","en"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","London"],["dc.relation.isbn","978-3-540-19839-0"],["dc.relation.ispartof","ICANN ’93"],["dc.title","Map Structure from Pinwheel Position"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","367"],["dc.bibliographiccitation.journal","Neurocomputing"],["dc.bibliographiccitation.lastpage","374"],["dc.bibliographiccitation.volume","26-27"],["dc.contributor.author","Ernst, Udo"],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Geisel, Theo"],["dc.date.accessioned","2017-09-07T11:46:13Z"],["dc.date.available","2017-09-07T11:46:13Z"],["dc.date.issued","1999"],["dc.description.abstract","In many experiments it has been found that stimuli outside the classical receptive-field of orientation-selective cells in the visual cortex can strongly modulate the response properties of these cells. Typically, stimuli with orientation contrasts lead to enhancement, whereas iso-orientation stimuli lead to suppression of the neuronal activity, but these phenomena in general depend in a complicate manner on various parameters like stimulus configuration, contrast, and geometry. In this contribution, we develop a simple theory for such non-classical receptive-field phenomena. We explain the basic mechanisms by a fixed-point analysis. Within this analysis, center-surround experiments can be described by trajectories in parameter space. This allows for a systematic variation of the coupling and stimulation constants. We show that the strength or sign of the enhancement or suppression should not only vary with the experimental paradigm but also with the position of the cell within the cortex. Our results suggest that non-classical receptive-field phenomena are mediated through orientation-specific lateral excitatory interactions."],["dc.identifier.doi","10.1016/s0925-2312(99)00026-0"],["dc.identifier.gro","3151865"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8695"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.relation.issn","0925-2312"],["dc.subject","Receptive fields; Visual cortex; Orientation contrast sensitivity; Fixed-point analysis; Center-surround phenomena"],["dc.title","Theory of non-classical receptive field phenomena in the visual cortex"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","97"],["dc.bibliographiccitation.lastpage","101"],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Kim, Douglas S."],["dc.contributor.author","Bonhoeffer, Tobias"],["dc.contributor.editor","Eeckman, Frank H."],["dc.date.accessioned","2017-09-07T11:45:41Z"],["dc.date.available","2017-09-07T11:45:41Z"],["dc.date.issued","2011"],["dc.description.abstract","We propose a mathematical description for the spatial organization of orientation preference in the visual cortex. The theory is derived from the principle of optimal smoothness and predicts the spatial pattern of orientation preference from position and chirality of its singularities (i.e. “pinwheels”). The model exhibits long range order in the sense that, given the configuration of singularities, the specification of orientation preference at a single location fixes the entire map. A comparison with optically recorded images of cortical maps suggests that orientation preference can indeed be predicted over a much larger spatial range than previously estimated on the basis of correlation measurements."],["dc.identifier.doi","10.1007/978-1-4615-2714-5_16"],["dc.identifier.gro","3151843"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8670"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","Boston, MA"],["dc.relation.isbn","978-1-4613-6169-5"],["dc.relation.ispartof","Computation in Neurons and Neural Systems"],["dc.title","Optimal Smoothness of Orientation Preference Maps"],["dc.type","book_chapter"],["dc.type.internalPublication","no"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.editor","Bower, James M."],["dc.date.accessioned","2017-09-07T11:46:13Z"],["dc.date.available","2017-09-07T11:46:13Z"],["dc.date.issued","2011"],["dc.description.abstract","The formation of feature-maps in the developing visual cortex has become a central system for the study of cooperative phenomena in large neural networks, both theoretically[1, 2] and experimentally [3, 4]. With advanced optical imaging techniques [5, 6] it is now possible to monitor the activity of neural populations synchronously with a high spatial resolution. This kind of measurement should finally enable a comparison of experiment and mathematical theory in quantitative detail. In this contribution we start to outline the respective contributions of linear and nonlinear dynamics in the development of visual cortical maps, the different timescales, on which these qualitatively distinct processes take place and how their effects might be accessed experimentally in a quantitative fashion."],["dc.identifier.doi","10.1007/978-1-4615-2235-5_59"],["dc.identifier.gro","3151867"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8698"],["dc.language.iso","en"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","Boston, MA"],["dc.relation.isbn","978-1-4613-5940-1"],["dc.relation.ispartof","The Neurobiology of Computation"],["dc.title","Linear and Nonlinear Dynamics in the Development of Orientation Preference Maps"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Bauer, H.-U."],["dc.contributor.author","Wolf, F."],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Geisel, Theo"],["dc.date.accessioned","2017-11-22T09:04:27Z"],["dc.date.available","2017-11-22T09:04:27Z"],["dc.date.issued","1998"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10175"],["dc.language.iso","en"],["dc.notes.status","new -primates"],["dc.publisher","University of Bremen, Department of Physics"],["dc.title","Unique orientation maps from stochastic self-organization"],["dc.type","report"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","103"],["dc.bibliographiccitation.lastpage","109"],["dc.contributor.author","Wolf, F."],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Deppisch, J."],["dc.contributor.editor","Eeckman, Frank H."],["dc.date.accessioned","2017-11-21T14:15:58Z"],["dc.date.available","2017-11-21T14:15:58Z"],["dc.date.issued","1994"],["dc.description.abstract","Oscillatory neuronal responses have been suspected to reveal assembly formation via synchronization. We analyse these data in terms of a hidden-state model, the parameters of which are estimated directly from experimental spike trains. The model characterizes the excitation dynamics of the network which is reflected by the stochastic activity of individual observed neurons. Our approach reproduces the spike dynamics observed in cat visual cortex and predicts the cross-correlations of units which belong to the same assembly."],["dc.identifier.doi","10.1007/978-1-4615-2714-5_17"],["dc.identifier.gro","3151869"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10155"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","Boston, MA"],["dc.relation.isbn","978-1-4613-6169-5"],["dc.relation.ispartof","Computation In Neurons And Neural System"],["dc.title","Network Dynamics and Correlated Spikes"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","361"],["dc.bibliographiccitation.lastpage","366"],["dc.contributor.author","Ernst, Udo"],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.editor","Bower, James M."],["dc.date.accessioned","2017-09-07T11:45:41Z"],["dc.date.available","2017-09-07T11:45:41Z"],["dc.date.issued","1998"],["dc.description.abstract","Recently Sillito and coworkers18,12 demonstrated that Stimulation beyond the classical receptive field (RF) can not only modulate, but radically change a neuron\\’s response to oriented stimuli. They revealed that patch-suppressed cells when stimulated with contrasting orientations inside and outside their classical RF can strongly respond to stimuli oriented orthogonal to their nominal preferred orientation."],["dc.identifier.doi","10.1007/978-1-4615-4831-7_60"],["dc.identifier.gro","3151842"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8669"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","Boston, MA"],["dc.relation.doi","10.1007/978-1-4615-4831-7"],["dc.relation.eisbn","978-1-4615-4831-7"],["dc.relation.isbn","978-1-4613-7190-8"],["dc.relation.ispartof","Computational Neuroscience"],["dc.title","Orientation Contrast Enhancement Modulated by Differential Long-Range Interactions in Visual Cortex"],["dc.type","book_chapter"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","525"],["dc.bibliographiccitation.issue","5-6"],["dc.bibliographiccitation.journal","Journal of Physiology-Paris"],["dc.bibliographiccitation.lastpage","537"],["dc.bibliographiccitation.volume","94"],["dc.contributor.author","Wolf, F."],["dc.contributor.author","Pawelzik, K."],["dc.contributor.author","Scherf, O."],["dc.contributor.author","Geisel, T."],["dc.contributor.author","Löwel, S."],["dc.date.accessioned","2017-09-07T11:46:16Z"],["dc.date.available","2017-09-07T11:46:16Z"],["dc.date.issued","2000"],["dc.description.abstract","The pattern of ocular dominance columns in primary visual cortex of mammals such as cats and macaque monkeys arises during development by the activity-dependent refinement of thalamocortical connections. Manipulating visual experience in kittens by the induction of squint leads to the emergence of ocular dominance columns with a larger size and larger column-to-column spacing than in normally raised animals. The mechanism underlying this phenomenon is presently unknown. Theory suggests that experience cannot influence the spacing of columns if the development proceeds through purely Hebbian mechanisms. Here we study a developmental model in which Hebbian mechanisms are complemented by activity-dependent regulation of the total strength of afferent synapses converging onto a cortical neurone. We show that this model implies an influence of visual experience on the spacing of ocular dominance columns and provides a conceptually simple explanation for the emergence of larger sized columns in squinting animals. Assuming that during development cortical neurones become active in local groups, which we call co-activated cortical domains (CCDs), ocular dominance segregation is controlled by the size of these groups: (1) Size and spacing of ocular dominance columns are proportional to the size σ of CCDs. (2) There is a critical size σ of CCDs such that ocular dominance columns form if σ<σ but do not form spontaneously if σ>σ . This critical size of CCDs is determined by the correlation functions of activity patterns in the two eyes and specifies the influence of experience on ocular dominance segregation. We show that σ is larger with squint than with normal visual experience. Since experimental evidence indicates that the size of CCDs decreases during development, ocular dominance columns are predicted to form earlier and with a larger spacing in squinters compared to normal animals."],["dc.identifier.doi","10.1016/s0928-4257(00)01104-9"],["dc.identifier.gro","3151873"],["dc.identifier.pmid","11165917"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8704"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.notes.submitter","chake"],["dc.relation.issn","0928-4257"],["dc.title","How can squint change the spacing of ocular dominance columns?"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Wolf, F."],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Riesenhuber, M."],["dc.contributor.author","Geisel, Theo"],["dc.date.accessioned","2017-11-21T13:49:02Z"],["dc.date.available","2017-11-21T13:49:02Z"],["dc.date.issued","1994"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10151"],["dc.language.iso","en"],["dc.notes.status","final"],["dc.publisher","Thieme Verlag"],["dc.publisher.place","Stuttgart"],["dc.relation.eventend","1994-05-29"],["dc.relation.eventlocation","Göttingen"],["dc.relation.eventstart","1994-05-27"],["dc.relation.ispartof","Göttingen Neurobiology Report"],["dc.title","Emergence of long range order in maps of orientation preference"],["dc.type","conference_paper"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","38"],["dc.bibliographiccitation.journal","Spektrum Der Wissenschaft"],["dc.bibliographiccitation.volume","4"],["dc.contributor.author","Bauer, Hans-Ulrich"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Wolf, Fred"],["dc.date.accessioned","2017-11-22T09:33:12Z"],["dc.date.available","2017-11-22T09:33:12Z"],["dc.date.issued","1996"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10179"],["dc.language.iso","de"],["dc.notes.status","final"],["dc.title","Selbstorganisierende neuronale Karten"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]