Mechanisms for Perceptual Decision-Making in the Human Brain

Findings from the activity of individual neurons suggest that a comparison of the outputs of different pools of selectively tuned lower-level sensory neurons may be a general mechanism by which higher-level regions of the cerebral cortex compute perceptual decisions. For example, when monkeys must decide whether a noisy field of dots is moving upward or downward, a decision can be made by computing the difference in responses between lower-level neurons sensitive to upward motion and those sensitive to downward motion. Dr. Ungerleider will present evidence from functional magnetic resonance imaging that even for high-level object categories, the comparison of the outputs of different pools of neurons could be a general mechanism by which the human brain computes perceptual decisions. She will also argue that the posterior dorsolateral prefrontal cortex in humans has general decision-making functions, independent of stimulus and response modalities, thereby providing a flexible link between sensory evidence, decision, and action.