Modulation of Human Reward Circuitry by Social Factors

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DESCRIPTION (provided by applicant): Motivated or goal-directed behaviors often abide by simple rules of reinforcement. That is, actions that lead to positive consequences tend to be repeated at a greater frequency, while actions that lead to negative consequences tend to be avoided. Fundamental research in non-human animals, complemented by an array of human neuroimaging studies, has delineated a basic neurocircuitry underlying reward-related learning and motivated behaviors. Such research has specifically identified circuits linking cortical structures and the basal ganglia, particularly its input unit - the striatum, a heterogeneous structure in terms of connectivity and functionality - as an interface for the processing of motor and motivational information. However, it is unclear how these basic mechanisms characterized by simple behaviors (e.g., learning that a button press leads to a reward) extend to more complex motivated behaviors typically displayed in society (e.g., learning that an individual is trustworthy and interactions will lead to rewards). The availability of social information and the prospects of social interactions are factors that challenge current thinking of how the brain processes reward and punishment feedback and how it uses such information to make decisions. The goal of this proposal is to use fMRI to investigate how social factors modulate the basic behavioral and neural mechanisms underlying reward-related processing as a precursor to understanding how social influences on motivated behavior impact well-being and mental health. Specifically, the proposed studies attempt to build on a solid and existing research foundation on the neural circuitry of reward-related processing by first: establishing the behavior and neural correlates of a simple task modeled after animal research and second: adding a social component to a similar task to investigate overlap in mechanisms. This approach allows for a translational method that, in future research, can also be further extended to developmental (e.g., the role of social feedback from a social network during adolescence) and clinical settings (e.g., social feedback during observational learning in autism). The proposed studies will investigate two aims. Specific Aim 1 - We will investigate how socially relevant feedback, such as reward feedback from a social network of peers, is processed in the brain and how it compares to non-social feedback. Specific Aim 2 - We will investigate how socially relevant feedback creates social expectations that influence mechanisms of reward-related learning and if such mechanisms are unaffected by non-social feedback. The studies outlined in the proposal will build on our knowledge of the role of corticostriatal systems during simple motivated behavior to probe the antecedents and consequences of social motivation, as a platform to understand how social behavior breaks down in clinical disorders in the future.