Neuron
Volume 80, Issue 6, 18 December 2013, Pages 1519-1531
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Article
Effects of Amygdala Lesions on Reward-Value Coding in Orbital and Medial Prefrontal Cortex

https://doi.org/10.1016/j.neuron.2013.09.036Get rights and content
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Highlights

  • Neurons in OFC and MFC differentially encode the reward value of stimuli

  • Lesions of the amygdala reduce reward coding in OFC but not in MFC

  • Amygdala lesions abolish differences between OFC and MFC in reward coding

  • Amygdala input is not necessary for reward coding in either OFC or MFC

Summary

We examined the contribution of the amygdala to value signals within orbital prefrontal cortex (OFC) and medial prefrontal cortex (MFC). On each trial, monkeys chose between two stimuli that were associated with different quantities of reward. In intact monkeys, as expected, neurons in both OFC and MFC signaled the reward quantity associated with stimuli. Contrasted with MFC, OFC contained a larger proportion of neurons encoding reward quantity and did so with faster response latencies. Removing the amygdala eliminated these differences, mainly by decreasing value coding in OFC. Similar decreases occurred in OFC immediately before and after reward delivery. Although the amygdala projects to both OFC and MFC, we found that it has its greatest influence over reward-value coding in OFC. Notably, amygdala lesions did not abolish value coding in OFC, which shows that OFC’s representations of the value of objects, choices, and outcomes depends, in large part, on other sources.

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