Evidence for model-based computations in the human amygdala during Pavlovian conditioning

PLoS Comput Biol. 2013;9(2):e1002918. doi: 10.1371/journal.pcbi.1002918. Epub 2013 Feb 21.

Abstract

Contemporary computational accounts of instrumental conditioning have emphasized a role for a model-based system in which values are computed with reference to a rich model of the structure of the world, and a model-free system in which values are updated without encoding such structure. Much less studied is the possibility of a similar distinction operating at the level of Pavlovian conditioning. In the present study, we scanned human participants while they participated in a Pavlovian conditioning task with a simple structure while measuring activity in the human amygdala using a high-resolution fMRI protocol. After fitting a model-based algorithm and a variety of model-free algorithms to the fMRI data, we found evidence for the superiority of a model-based algorithm in accounting for activity in the amygdala compared to the model-free counterparts. These findings support an important role for model-based algorithms in describing the processes underpinning Pavlovian conditioning, as well as providing evidence of a role for the human amygdala in model-based inference.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Amygdala / physiology*
  • Blinking / physiology
  • Conditioning, Classical / physiology*
  • Heart Rate / physiology
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Male
  • Models, Neurological*
  • Pupil / physiology
  • Respiratory Rate / physiology
  • Signal Processing, Computer-Assisted

Grant support

This work was funded by Science Foundation Ireland grant 08/IN.1/B1844 to JPOD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.