Jason Samonds, Brian Potetz, Tai Lee
Although there has been substantial progress in understanding the neuro- physiological 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 impor- tant for resolving ambiguity during stereo matching. To test these predic- tions, 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 non- preferred disparities. They experienced mutual facilitation later in their re- sponses for stimulation at their preferred disparity. These findings are con- sistent with a local competition mechanism that first removes gross mis- matches, and a global cooperative mechanism that further refines depth es- timates.