Decoding Of Ventral Intraparietal Area (VIP) Population Activity

Monkeys use both vestibular and visual motion (optic flow) cues to discriminate their direction of self-motion during navigation. Decoding of the self-motion direction by nervous system support behavior, and we want to know how nervous system coding and decoding the cue. The coding and decoding properties of single neuron and population neuron activities from ventral intraparietal area(VIP for short) are presented in this article. It is difficult to find regular pattern from decoding by sigle neuron.we get a striking property by population decoding of self-motion perception from optic flow is that discrimination is most precise when monkey judge small variations of self-motion direction around straight ahead, whereas thresholds rise precipitously when subjects judge self-motion direction around an eccentric direction. We used computational methods (Fisher information, maximum likelihood estimation, and population vector decoding) to show that population activity in area VIP predicts the dependence of direction thresholds on direction eccentricity. This dependence arises because the tuning functions for most neurons have a steep slope for directions near straight forward. Our findings support the notion that population activity in extrastriate cortex limits the precision of both visual and vestibular self-motion direction perception. Fisher information and maximum likelihood estimation show better result than population vector decoding.