paper on the dynamics of receptive fields

[German Mato]

The following paper on the dynamics of receptive 
fields in the visual cortex has been put into the 
Neuroprose repository.


Comments and suggestions are welcome.
Sorry, no hard copy available.

German Mato 	    and     Nestor Parga
gmato at delta.ft.uam.es       parga at ccuam3.sdi.uam.es

*****************************************************
FTP-host: archive.cis.ohio-state.edu
FTP-filename: /pub/neuroprose/parga.dynrf.ps.Z
44 pages


Abstract:

In this work we study the dynamical changes of receptive fields
in a system in which the input has a lesion. A two-layer architecture
representing the retina and V1 is introduced and the values of the
horizontal connections in the second layer are updated in such a way that
the (two-point and higher) correlations between the activities of different
cortical neurons are minimized. We find that this algorithm, with a
simultaneous dynamics for the activities of cortical neurons and for their 
horizontal connections, predicts several experimental facts: the expansion 
of the receptive fields, the bias in feature localization experiments and the
{\it filling-in} phenomenon (in which the lesion is "filled" with the
surrounding pattern after a time of adaptation). We find that
non-Hebbian terms in the updating rule for the horizontal connections
are essential to account quantitatively for the experimental results.