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: Because the lOFC and amygdala exhibited a similar lose-shift signal but different win-stay signals, it is possible that the connectivity between these two regions could also be modulated as a function of the outcome of a choice. To test this, we used the psychophysiological interaction (PPI) test (Friston et al., 1997) commonly used in fMRI studies. In this PPI analysis, we examined the impact on amygdala activity of the interaction of a physiological parameter, the lOFC activity (as indexed by the lOFC BOLD time series), and a psychological parameter indexed by a task variable (a contrast between the lose-shift contingency and the win-stay contingency). We focused on the interaction of these two influences (PPI effect) but took care to include both main effects in our analysis (O’Reilly et al., 2012). The lOFC and amygdala were more strongly coupled during lose-shift events than during win-stay events (t3 = 9.215, p = 0.003; Figure 5A). There was a relationship between the effect size of this change in coupling in different sessions and behavioral variation in the sessions; larger sizes of lose-shift coupling between lOFC and amygdala were present in testing sessions in which a higher proportion of lose trials were lose-shift trials (even after controlling for the proportion of win trials that were win-stay trials; Figure 5B; r = 0.476, p = 0.040).
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.