The efficacy of decision making is often measured by whether or not it leads to rewarding outcomes. Over the past decade, separate research programs have identified separate brain systems that contribute to decision making and to the evaluation of rewards. While the individuation of functionally specific regions within these systems remains an active and ongoing component of cognitive neuroscience, relatively little work has been devoted toward elucidating their interactions. This Project will investigate how reward information alters the functional properties of brain systems for decision making, through a combination of functional magnetic resonance imaging (fMRI), intracranial electrophysiological, and behavioral studies. This Project has four specific aims. First, it will determine the consequences of delivery of punctate monetary rewards upon the subsequent activation of brain systems underlying decision making. The experiments will test the hypothesis that rewards have a transient inhibitory effect upon lateral prefrontal regions associated with decision making, through comparison of the effects of performance-dependent and performance-independent rewards with those of other affective stimuli. Second, it will investigate how decision makers incorporate or ignore external recommendations that confirm or refute their prior decisions through experiments that systematically adjust the predictiveness of recommendations in obtaining rewarding decision outcomes. Key regions for the analysis include frontopolar, orbitofrontal and cingulate areas. Third, we will study how decision makers regulate tradeoffs between two factors that are often in opposition: risk and reward. In many situations, by delaying judgment, people pay opportunity costs (e.g., by passing up opportunities for large rewards) in order to make more accurate and confident decisions. The experiments will evaluate how observers manage these costs with insular and orbitofrontal regions targeted as key sites. The fourth and final aim will evaluate the relative timing and spatial specificity of reward effects upon prefrontal systems through the use of intracranial electrophysiology. Its experiments will take advantage of the improved temporal resolution of electrophysiology to characterize the relative timing of activation throughout prefrontal cortex associated with decisions about rewards. They will also provide new data about the function of orbitofrontal cortex, an area often difficult to image using fMRI. These experiments will have important consequences for the understanding of how people make decisions, set goals, and determine preferences among stimuli. A better understanding of these processes will lead to further improvements in clinical remediation of neurological and psychiatric disorders characterized by impairments in executive function, behavioral selection, or stimulus valuation (e.g., frontal lobe damage, schizophrenia. Parkinson's disease).
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