Neural Mechanisms of Social Reward Valuation and Decision Making

Duke University, Durham NC

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Abstract

DESCRIPTION (provided by applicant): Social contexts are rife with uncertainty. Consequently, much of our sensory apparatus and cognitive skill is applied to reducing this volatility by acquiring information about others. The brain mechanisms that evaluate social information and translate it into decisions, however, remain poorly understood-despite clear dysfunction of these mechanisms in neurological disorders such as autism, social anxiety, and anorexia which are characterized by dysfunctional social motivation and decision making. We hypothesize that social signals are first decoded by several distinct brain areas, including superior temporal sulcus (STS) and amygdala, translated into value signals in the ventral striatum (VS), and transformed into a common currency for comparison and exchange with other types of rewards in the orbital (OFC) and medial prefrontal cortex (mPFC). We propose to use complementary fMRI techniques in human subjects and electrophysiological techniques in macaques to test this hypothesis. Critically, we will use the same psychophysical technique to estimate reward functions for social stimuli in humans and monkeys, thus validating our comparison. Crucially, temporary inactivation of nodes in this network in monkeys and comparison with fMRI results in a high-functioning clinical population with social dysfunction will be used to functionally evaluate our model. The brain mechanisms that evaluate social information and translate it into decisions remain poorly understood-despite clear dysfunction of these mechanisms in neurological disorders such as autism, social anxiety, and anorexia nervosa which are characterized by dysfunctional social motivation and decision making. We hypothesize that social signals are first decoded by several distinct brain areas, including superior temporal sulcus (STS) and amygdala, translated into value signals in the ventral striatum (VS), and transformed into a common currency for comparison and exchange with other types of rewards in the orbital (OFC) and medial prefrontal cortex (mPFC). We will use complementary fMRI techniques in human subjects and electrophysiological techniques in macaques to test this hypothesis, and functionally validate these observations by determining the locus of dysfunctional social reward processing in a psychiatric population characterized by maladaptive social behavior.