主题：Primate posterior parietal cortex plays a causal role in mediating visual decisions
报告人：Dr. Yang Zhou, The University of Chicago
Decision making requires evaluating incoming sensory stimuli in order to select task-appropriate motor responses. The primate posterior parietal cortex (PPC) is well suited to mediate decision making and its activity correlates with monkeys’ decisions during visual discrimination and categorization tasks. However, recent work has questioned whether decision-correlated PPC activity plays a causal role in such decisions. That study focused on PPC’s contribution to motor aspects of decisions (deciding where to move), but not sensory evaluation aspects (deciding what you are looking at). We employed reversible inactivation to compare PPC’s contributions to motor and sensory aspects of decisions. Inactivation affected both aspects of behavior, but preferentially impaired decisions when visual stimuli, rather than motor response targets, were in the inactivated visual field. To further test LIP’s role in sensory evaluation during perceptual decisions, we recorded neuronal activity in the same LIP regions targeted for inactivation. This revealed neuronal activity that was highly correlated with monkeys’ trial-by-trial decisions about the stimuli shown within neurons’ RFs. These results demonstrate that the primate PPC plays a significant role in mediating visual decisions, with a preferential role in sensory evaluation compared to motor planning during visual perceptual and categorical decision-making tasks. Our work requires a major revision of the classic decision framework which has dominated the field for several decades, and establishes the PPC as a key stage for sensory aspects of decision making—extending beyond PPC’s widely recognized role in visual-spatial functions.