ELECTRICAL MICROSTIMULATION OF CORTICAL AREA MST BIASES HEADING PERCEPTION IN MONKEYS

As we move through the environment, the pattern of visual motion on th e retina provides rich information about our movement through the scen e. Human subjects can use this information, often termed ''optic flow' ', to accurately estimate their direction of self movement (heading) f rom relatively sparse displays. Physiological observations on the moti on-sensitive areas of monkey visual cortex suggest that the medial sup erior temporal area (MST) is well suited for the analysis of optic Row information. To test whether MST is involved in extracting heading fr om optic flow, we perturbed its activity in monkeys trained on a headi ng discrimination task. Electrical microstimulation of MST frequently biased the monkeys' decisions about their heading, and these induced b iases were often quite large. This result suggests that MST has a dire ct role in the perception of heading from optic flow.