Intracranial dynamics of Reward Positivity associated with Impulsive Choice

Poster Session A - Saturday, April 13, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC
Also presenting in Data Blitz Session 2 - Saturday, April 13, 2024, 1:00 – 2:30 pm EDT, Ballroom Center.

Rhiannon L. Cowan¹ (rhiannon.cowan@utah.edu), Tyler S. Davis¹, Bornali Kundu², Ben Shofty¹, Shervin Rahimpour¹, John D. Rolston³, Elliot H. Smith¹; ¹University of Utah, ²University of Missouri, ³Brigham & Women's Hospital and Harvard Medical School

Reward positivity (RewP) is an event-related potential (ERP) component occurring around 250ms after a rewarded outcome. RewP amplitude is dependent on reward outcome feedback, including the expected value of reward and prediction error related to the reward outcome. RewP amplitude has been shown to vary based on impulsivity level, with greater reward sensitivity in more impulsive (MI) individuals. However, the interactions between RewP and impulsivity have not been disentangled utilizing spatially precise intracranial recordings. We used the Balloon Analog Risk Task to assess ERP, frequency dynamics, and neural encoding associated with intracranial RewP (200-400ms), recorded from 49 drug-resistant epilepsy patients. Using the Kullback-Leibler divergence between active and passive balloon inflation times as a measure of impulsive choice, we clustered subjects into more- or less-impulsive choosers, to further scrutinize potential group-level differences between RewP characteristics in specific brain regions. We saw increased delta activity and decreased theta activity encoding for MI choosers for rewarded vs unrewarded trials compared to LI choosers (Delta, MI: 237, LI: 213; χ2 =6.72, p =0.009; Theta, MI: 138, LI: 115; χ2 =6.35, p =0.012). For MI choosers, Delta-band activity was uniquely encoded in middle frontal gyrus (MFG) (17%), while theta-band activity was uniquely encoded in Anterior Cingulate Cortex (9%) and MFG (22%). We extend previous win-related delta and loss-related theta frequency findings differentiating between impulsivity groups and highlighting unique RewP encoding in the brain for MI individuals. Future work will scrutinize the neural underpinnings of reward and examine RewP relative to temporal difference modeling.

Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching