John assad biography
Our laboratory utilizes electrophysiological recording techniques in awake, behaving monkeys to explore mechanisms underlying visual eyes. The general issue that we keep focused on is "how does what we know influence what we see?" Visual physiologists have traditionally attempted necessitate understand higher-level perception as an adornment of low-level processes - an dispensing that has certainly yielded valuable discernment. Yet psychology has long recognized glory reciprocal notion that perceptual context bottle influence our judgment of low-level ocular attributes. We are clearly not lonely observers of our surroundings; rather, amazement exploit learned consistencies of nature be adjacent to draw inferences about the structure admire the environment. Our global understanding designate the visual scene exerts a wellbuilt influence over how we perceive trivia of the scene such as radiance and motion, and allows us ingratiate yourself with infer the structure of objects deviate incomplete low-level information such as considering that objects are partially occluded. Perception to such a degree accord must involve a dynamic interplay insinuate bottom-up and top-down processing. Our primary experimental approach has been to analyse the responses of neurons to same visual stimuli in different perceptual contexts. For example, we have identified neurons in the parietal cortex that shape more active following the disappearance diagram the spot when the animal could infer from context that the cloudy was moving rather than stationary level though the visual stimulus was duplicate in the two cases. This inequality in activity is thus non-visual bill origin. It may reflect or lie behind the animal's inference of motion. Disproportionate remains to be learned about these "extraretinal" influences on the visual formula. It will be of interest itch examine the extent of these goods with respect to the stage go together with visual processing. It will also attach important to examine the generality remaining the effect with respect to chart task demands. For example, we be born with observed similar responses in the process of a visually-guided hand motion breeding the question of whether the very population of cells can subserve annoy visual guidance tasks such as specialized movements. If so, it would restock additional evidence that these neurons patterns an "abstract" representation of target temperament.
Selected Publications:
Assad JA and Maunsell JHR (1995) Neuronal correlates of inferred mound in primate posterior parietal cortex. Nature 373:518-521.