Choosing between two items involves deliberation and comparison of the features of each item and its value. Such decisions take more time when choosing between options of similar value, possibly because these decisions require more evidence, but the mechanisms involved are not clear. We propose that the hippocampus supports deliberation about value, given its well-known role in prospection and relational cognition. We assessed the role of the hippocampus in deliberation in two experiments. First, using fMRI in healthy participants, we found that BOLD activity in the hippocampus increased as a function of deliberation time. Second, we found that patients with hippocampal damage exhibited more stochastic choices and longer reaction times than controls, possibly due to their failure to construct value based on internal evidence during deliberation. Both sets of results were stronger in value-based decisions compared to perceptual decisions.
- Daphna Shohamy
- Akram Bakkour
- Michael N Shadlen
- Michael N Shadlen
- Mieke Verfaellie
- Yul HR Kang
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. The contents of this manuscript do not represent the view of the US Department of Veterans Affairs or the US Government.
Human subjects: Experimental procedures in Experiment 1 were approved by the Institutional Review Board (IRB) at Columbia University through Columbia IRB Protocol #AAAO5907. All fMRI participants provided signed informed consent before taking part in the study. All patients and age-matched healthy participants in experiment 2 provided informed consent in accordance with the Institutional Review Boards at Boston University and the VA Boston Healthcare System outlined in VABHS IRB #2997.
- Thorsten Kahnt, Northwestern University Feinberg School of Medicine, United States
- Received: February 25, 2019
- Accepted: June 29, 2019
- Accepted Manuscript published: July 3, 2019 (version 1)
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