Representation of decision uncertainty in the brain during hypothesis testing

Poster Session E - Monday, April 15, 2024, 2:30 – 4:30 pm EDT, Sheraton Hall ABC

Xinxu Shen¹ (tul04056@temple.edu), David Smith, Vishnu Murty; ¹Temple University

Understanding how humans seek and process information under uncertainty is fundamental to our decision-making processes and adaptive behaviors. Behaviorally, we have found that individuals will seek information to reduce uncertainty via hypothesis testing to resolve goal-oriented behavior However, little is known about the neural mechanisms underlying these hypothesis-testing processes. Therefore, we designed a fMRI study to investigate the neural mechanisms behind hypothesis testing. In the task, 20 participants were presented with three stimuli, each consisting of one feature on three different dimensions. Participants were instructed to figure out the target feature to open a treasure chest. The Target feature changed after four consecutive choices of the stimulus with the target feature. Analysis using a reinforcement learning model revealed decreasing decision uncertainty before a feature switch, indicating effective hypothesis testing during the task. Neuroimaging analyses indicated that activation in the ventromedial prefrontal cortex (VMPFC) decreased as a function of increasing decision uncertainty (ROI analysis, p < 0.01), while frontoparietal network activation positively correlated with decision uncertainty (whole-brain corrected). We speculate that as participants systematically tested features, VMPFC activation increased corresponding to successful goal achievement as decision uncertainty decreased, while frontoparietal networks were engaged to help resolve uncertainty. In summary, our findings highlight the significance of VMPFC and the frontoparietal network in representing decision uncertainty during hypothesis testing.

Topic Area: LONG-TERM MEMORY: Episodic