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My current research is focused on the mechanisms underlying processing and storage of visual motion information in primate cortex. In our studies we combine single cell recordings, microstimulation, reversible inactivation with psychophysical measures of visual performance. We have shown that neurons in visual cortical area MT, strongly associated with processing of visual motion, also participate in the storage and the retrieval/comparison operations required by working memory tasks. Recordings from prefrontal cortex, a likely source of cognitive signals, during the performance of the same memory tasks revealed prevalence of motion selective signals that were strongly modulated by task demands. These signals most likely originated in area MT and their nature suggests that prefrontal neurons have access to the basic mechanisms underlying motion selectivity of MT neurons. We also found that neuronal activity of both areas recorded during different stages of the task is predictive of the monkey's decision. This work suggests that prefrontal cortex together with area MT actively participate in the performance of working memory for motion tasks. Our current efforts are focused on elucidating the nature of dynamic interactions between these two areas as well as on identifying other components of the circuitry underlying the ability to discriminate and store visual motion signals.
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