PBIO SEMINAR SERIES

Circuitry of object motion sensitivity in the retina

Wednesday - March 29, 2006
05-06 SEMINAR SERIES
T-739

Steve Baccus
Stanford University
Speaker's website

Host: Peter Detwiler

Our vision is very sensitive to small movements of an object within the scene, but we are perceptually blind to the much larger retinal image drift caused by eye movements that are present even when we fixate. This perceptual suppression of fixational eye movements appears to originate in the retina. Object Motion Sensitive (OMS) ganglion cells respond to local motion, but are nearly silent if the entire visual field moves together. This property can be explained quantitatively by a circuit that consists of small bipolar cells whose output is summed nonlinearly both by OMS ganglion cells and inhibitory polyaxonal amacrine cells, whose axons extend across the entire retina. Strong, transient amacrine inhibition acts as a blanking circuit, suppressing global motion from eye movements, but sparing differential motion from objects.