direkt zum Inhalt springen

direkt zum Hauptnavigationsmenü

Sie sind hier

TU Berlin

Page Content

All Publications

A Model for Orientation Tuning and Contextual Effects of Orientation Selective Receptive Fields
Citation key Bartsch1997
Author Bartsch, H. and Stetter, M. and Obermayer, K.
Title of Book Artificial Neural Networks - ICANN 97
Pages 237 – 242
Year 1997
ISBN 978-3-540-63631-1
ISSN 0302-9743
DOI 10.1007/BFb0020162
Note 7th International Conference Lausanne, Switzerland, October 8–10, 1997 Proceeedings
Editor W. Gerstner and A. Germond and M. Hasler and J. Nicoud
Publisher Springer Berlin Heidelberg
Abstract We investigate a meanfield model which has previously been used to explain the response properties of orientation selective neurons in the primary visual cortex of monkeys and cats [Ben-Yishai et al. 1995]. Two mutually coupled orientation hypercolumns are setup as local amplifiers based on local recurrent excitation and inhibition. We first investigate the individual h yp ercolumns. The mo del correctly predicts contrast invariant tuning, but analytical and numerical results show that the contrast response functions of individual orientation columns do not saturate. We therefore hypothesize that the cortical saturation effects found experimentally may be a consequence of the non-linear properties of single neurons rather than being an effect of different gains for inhibitory and excitatory cells [Todorov et al. 1996]. We then extend this model to cover non-classical receptive fields and con textual effects. The model correctly predicts effective iso-orientation inhibition between hypercolumns. As long as parameters are chosen to ensure contrast invariant orientation tuning, however, net cross-orientation facilitation emerges only, if cells of different orientation preference are connected across hypercolumns. These results hint at deficiencies of this simple approach and suggest that contextual effects are mediated by populations of neurons, which are not part of the local gain control.
Link to publication Link to original publication Download Bibtex entry

Zusatzinformationen / Extras

Quick Access:

Schnellnavigation zur Seite über Nummerneingabe

Auxiliary Functions