Pawelzik, Klaus Richard

[["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","Scherf, O."],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Wolf, Fred"],["dc.contributor.author","Geisel, Theo"],["dc.contributor.editor","Marinaro, Maria"],["dc.contributor.editor","Morasso, Pietro G."],["dc.date.accessioned","2017-09-07T11:46:12Z"],["dc.date.available","2017-09-07T11:46:12Z"],["dc.date.issued","2012"],["dc.description.abstract","Selforganizing feature maps serve as models for the organization of primary sensory areas and have many applications in technical pattern recognition. In most models the evolution of receptive field centers w : X → Ω is driven by the excitation ew(υ) in the neuronal tissue: ẇ =< (υ - w)ew(υ) >, where < … >, denotes the average over the stimulus distribution P(υ). The models differ, however, in the way ew(υ) is determined. In the Kohonen model [1] a hard competition for the stimulus takes place and the excitation then spreads into the neighborhood of the winning neuron. This very effcient algorithm, however, generates only simple network excitations, which is biologically unrealistic. Complementary to that, the elastic net algorithm [2] uses a neighborhood in input space. Here, however, the”elastic” neuronal interaction has no obvious biological interpretation. In this contribution we present a model unifying both approaches. The elastic net and the Kohonen model turn out to be asymptotic cases of this convolution model. For the elastic net we obtain the elasticity parameter β directly from a small, but finite neighborhood range in the neuronal layer."],["dc.identifier.doi","10.1007/978-1-4471-2097-1_79"],["dc.identifier.gro","3151854"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/8683"],["dc.language.iso","en"],["dc.notes.status","public"],["dc.notes.submitter","chake"],["dc.publisher","Springer"],["dc.publisher.place","London"],["dc.relation.isbn","978-3-540-19887-1"],["dc.relation.ispartof","Proceedings of the International Conference on Artificial Neural Networks, Sorrento, Italy, 26 - 29 May 1994: Parts 1 and 2"],["dc.title","Unification of Complementary Feature Map Models"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.contributor.author","Scherf, O."],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Wolf, F."],["dc.contributor.author","Geisel, Theo"],["dc.date.accessioned","2017-11-22T07:53:24Z"],["dc.date.available","2017-11-22T07:53:24Z"],["dc.date.issued","1995"],["dc.format.extent","94"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10169"],["dc.language.iso","en"],["dc.notes.status","new -primates"],["dc.publisher","Thieme Verlag"],["dc.publisher.place","Stuttgart"],["dc.relation.ispartof","Learning and Memory, Proceedings of the 23rd Göttingen Neurobiology Conference"],["dc.title","Correlation dependence of ocular dominance patterns requires receptive field shrinkage during development"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.volume","2"],["dc.bibliographiccitation.volumetitle","Göttingen Neurobiology Report"],["dc.contributor.author","Scherf, O."],["dc.contributor.author","Pawelzik, Klaus"],["dc.contributor.author","Wolf, F."],["dc.contributor.author","Geisel, Theo"],["dc.contributor.author","Löwel, Siegrid"],["dc.contributor.editor","Elsner, Norbert"],["dc.date.accessioned","2017-11-22T07:56:52Z"],["dc.date.available","2017-11-22T07:56:52Z"],["dc.date.issued","1994"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/10170"],["dc.language.iso","en"],["dc.notes.status","zu prüfen"],["dc.publisher","Thieme Verlag"],["dc.publisher.place","Stuttgart"],["dc.relation.ispartof","Proceedings of the 22nd Göttingen Neurobiology Conference 1994"],["dc.title","A simple method for determining the typical periodicity length of ocular dominance patterns"],["dc.type","book_chapter"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]