Contrast-dependence of surround suppression in Macaque V1: experimental testing of a recurrent network model.

ABSTRACT: Neuronal responses in primary visual cortex (V1) to optimally oriented high-contrast stimuli in the receptive field (RF) center are suppressed by stimuli in the RF surround, but can be facilitated when the RF center is stimulated at low contrast. The neural circuits and mechanisms for surround modulation are still unknown. We previously proposed that topdown feedback connections mediate suppression from the "far" surround, while "near' surround suppression is mediated primarily by horizontal connections. We implemented this idea in a recurrent network model of V1. A model assumption needed to account for the contrast-dependent sign of surround modulation is a response asymmetry between excitation and inhibition; accordingly, inhibition, but not excitation, is silent for weak visual inputs

SUBMITTER: Schwabe L 

PROVIDER: S-EPMC2902655 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature