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Poster Session A: Tuesday, August 12, 1:30 – 4:30 pm, de Brug & E‑Hall

One-shot reinforcement learning decisions engage the hippocampus

Christopher S. Iyer¹, Raphael T Gerraty¹, Katherine D. Duncan, Nathaniel D. Daw², Daphna Shohamy¹; ¹Columbia University, ²Princeton University

Presenter: Christopher S. Iyer

Decisions about value can be based on multiple sources of information from memory. Classic reinforcement learning models describe how value estimates are incrementally learned over many trials, while decisions can also be guided by “one-shot” episodic memories for single experiences. The goal of this study is to better understand the contribution of these two processes—incremental learning and episodic memory—to value-based decisions. Human participants were scanned with fMRI while performing a decision task in which choices could be guided by either incremental and episodic information. Choices based on episodic information were associated with increased BOLD activity in the hippocampus. Intriguingly, hippocampal activity was also associated with incrementally-learned value information, derived from reinforcement learning models. Finally, we observed reward-related reinstatement of patterns during episodic decisions in the ventromedial prefrontal cortex. These findings reveal both shared and distinct markers of incremental and episodic memory during value-based decisions.

Topic Area: Reward, Value & Social Decision Making

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