Effects of Amygdala Lesions on Object-Based Versus Action-Based Learning in Macaques

Craig A. Taswell, Vincent D. Costa, Benjamin M. Basile, Maia S. Pujara, Breonda Jones, Nihita Manem, Elisabeth A. Murray, Bruno B. Averbeck

Research output: Contribution to journalArticlepeer-review

Abstract

The neural systems that underlie reinforcement learning (RL) allow animals to adapt to changes in their environment. In the present study, we examined the hypothesis that the amygdala would have a preferential role in learning the values of visual objects. We compared a group of monkeys (Macaca mulatta) with amygdala lesions to a group of unoperated controls on a two-armed bandit reversal learning task. The task had two conditions. In the What condition, the animals had to learn to select a visual object, independent of its location. And in the Where condition, the animals had to learn to saccade to a location, independent of the object at the location. In both conditions choice-outcome mappings reversed in the middle of the block. We found that monkeys with amygdala lesions had learning deficits in both conditions. Monkeys with amygdala lesions did not have deficits in learning to reverse choice-outcome mappings. Rather, amygdala lesions caused the monkeys to become overly sensitive to negative feedback which impaired their ability to consistently select the more highly valued action or object. These results imply that the amygdala is generally necessary for RL.

Original languageEnglish (US)
Pages (from-to)529-546
Number of pages18
JournalCerebral Cortex
Volume31
Issue number1
DOIs
StatePublished - Jan 1 2021

Keywords

  • Bayesian modeling
  • monkeys
  • reversal learning

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience

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