A critical role for the hippocampus in the valuation of imagined outcomes

PLoS Biol. 2013 Oct;11(10):e1001684. doi: 10.1371/journal.pbio.1001684. Epub 2013 Oct 22.

Abstract

Many choice situations require imagining potential outcomes, a capacity that was shown to involve memory brain regions such as the hippocampus. We reasoned that the quality of hippocampus-mediated simulation might therefore condition the subjective value assigned to imagined outcomes. We developed a novel paradigm to assess the impact of hippocampus structure and function on the propensity to favor imagined outcomes in the context of intertemporal choices. The ecological condition opposed immediate options presented as pictures (hence directly observable) to delayed options presented as texts (hence requiring mental stimulation). To avoid confounding simulation process with delay discounting, we compared this ecological condition to control conditions using the same temporal labels while keeping constant the presentation mode. Behavioral data showed that participants who imagined future options with greater details rated them as more likeable. Functional MRI data confirmed that hippocampus activity could account for subjects assigning higher values to simulated options. Structural MRI data suggested that grey matter density was a significant predictor of hippocampus activation, and therefore of the propensity to favor simulated options. Conversely, patients with hippocampus atrophy due to Alzheimer's disease, but not patients with Fronto-Temporal Dementia, were less inclined to favor options that required mental simulation. We conclude that hippocampus-mediated simulation plays a critical role in providing the motivation to pursue goals that are not present to our senses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Alzheimer Disease / pathology
  • Alzheimer Disease / physiopathology
  • Atrophy / pathology
  • Atrophy / physiopathology
  • Brain Mapping
  • Choice Behavior
  • Decision Making
  • Female
  • Frontotemporal Dementia / pathology
  • Frontotemporal Dementia / physiopathology
  • Health
  • Hippocampus / pathology
  • Hippocampus / physiopathology*
  • Humans
  • Imagination*
  • Impulsive Behavior / pathology
  • Impulsive Behavior / physiopathology
  • Magnetic Resonance Imaging
  • Male
  • Task Performance and Analysis

Grant support

The study was funded by a Starting Grant for the European Research Council (ERC-BioMotiv), the Emergence Program from the Ville de Paris, and a Research Grant from the Schlumberger Foundation. ML and MB received PhD fellowships from the Ministère de la Recherche and the Direction Générale de l'Armement, respectively. This work also benefited from the program “Investissements d'avenir”?(ANR-10-IAIHU-06). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.