Contrasting Roles for Orbitofrontal Cortex and Amygdala in Credit Assignment and Learning in Macaques.
Bottom Line: Recent studies have challenged the view that orbitofrontal cortex (OFC) and amygdala mediate flexible reward-guided behavior.A second experiment confirmed the existence of signals for adaptive stay/shift behavior in lOFC and reflecting irrelevant reward in the amygdala in a probabilistic learning task.Our data demonstrate that OFC and amygdala each make unique contributions to flexible behavior and credit assignment.
Affiliation: Department of Experimental Psychology, University of Oxford, OX1 3UD, Oxford, UK; Department of Psychology, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: email@example.com.Show MeSH
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Mentions: Whether or not reward had been received on a previous trial did not influence decision and outcome-related activity on subsequent trials in lOFC (t3 = 0.849, p = 0.458; Figure 6A). In contrast, the amygdala carried a previous reward signal throughout the course of the subsequent trial’s decision and outcome phases (t3 = 5.552, p = 0.012; Figure 6B), suggesting that the amygdala might mediate the assignment of the reward from a previous trial to an option chosen on the current trial and hence mediate a spread of reward effect. In a PPI analysis in which we examined the interacting influences of lOFC activity and the previous trial’s reward on amygdala activity, we found negative lOFC-amygdala coupling as a function of previous reward delivery (t3 = −7.207, p = 0.006; Figure 7A). In other words, the lOFC-amygdala connectivity was weaker when the amygdala itself was showing a signal related to reward delivery on the previous trial.
Affiliation: Department of Experimental Psychology, University of Oxford, OX1 3UD, Oxford, UK; Department of Psychology, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: firstname.lastname@example.org.