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Download fileNeurophysiological Evidence of Cooperative Mechanisms for Stereo Computation
journal contribution
posted on 2006-01-01, 00:00 authored by Jason M. Samonds, Brian Potetz, Tai Sing LeeAlthough there has been substantial progress in understanding the neurophysiological
mechanisms of stereopsis, how neurons interact in a network
during stereo computation remains unclear. Computational models on
stereopsis suggest local competition and long-range cooperation are important
for resolving ambiguity during stereo matching. To test these predictions,
we simultaneously recorded from multiple neurons in V1 of awake,
behaving macaques while presenting surfaces of different depths rendered
in dynamic random dot stereograms. We found that the interaction between
pairs of neurons was a function of similarity in receptive fields, as well as
of the input stimulus. Neurons coding the same depth experienced common
inhibition early in their responses for stimuli presented at their nonpreferred
disparities. They experienced mutual facilitation later in their responses
for stimulation at their preferred disparity. These findings are consistent
with a local competition mechanism that first removes gross mismatches,
and a global cooperative mechanism that further refines depth estimates.