Causal Dissociation of Value Contributions to the Reward Positivity

The aim of this proposal is to demonstrate that stimulation of different brain regions differently affects the electroencephalographic feature known as the Reward Positivity (RewP). The RewP is a sensitive and specific biomarker of reward receipt. This proposal will advance a causal test of the hypothesis that there are two major sources of variance that contribute to this brain response: a dorsal midline contribution to information encoding and a ventral midline contribution that is modulated by affect. Together, these findings will reveal how the RewP acts to blend multiple aspects of value together in the service of motivated learning. The objective of this proposal is to gather pilot data to demonstrate the feasibility of using transcranial magnetic stimulation (TMS) to perturb idiosyncratically-defined (fMRI-based) dorsal or ventral targets in order to causally test the hypothesis that these different sources contribute different types of variance to the RewP. TMS double cone deep coil stimulation should diminish +RPE encoding in the RewP when compared to sham. TMS Figure-8 coil stimulation should diminish affective modulation of RewP amplitude when compared to sham.