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- C. Piepenbrock
and K. Obermayer. Cortical Orientation Map Development from Natural
Images: the Role of Cortical Response Amplification in V1.
.
In W. Backhaus, editor, Neural Coding of Perceptual Systems, pages
161-168. World Scientific Publishers, 2001.
(FTP Gzipped PostScript, 8 pages, 122 kb)
Simple cells in the primary visual cortex respond selectively to
oriented stimuli. It has been proposed that such feature detecting neurons
should generate a sparse representation of the visual world and orientation
selective receptive fields are in this sense optimal spatial filters for
natural visual environments. In this contribution we show that a competitive
Hebbian development model driven by natural images may generate a topographic
projection from the lateral geniculate nucleus to the primary visual cortex
as well as orientation selective receptive fields. The resulting
representation is sparse and the degree of sparseness depends on the
recurrent dynamics, i.e., the lateral competition among the cortical neurons.
Simulations show that for weak competition, the resulting receptive fields
are global and unstructured and for intermediate competition, they refine and
a topographic projection emerges. Finally, in the case of strong competition,
the receptive fields act as oriented localized spatial filters arranged in a
typical orientation selectivity map.
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