Regional inactivations of primate ventral prefrontal cortex reveal two distinct mechanisms underlying negative bias in decision making

Dysregulation of the orbitofrontal and ventrolateral prefrontal cortices is implicated in anxiety and mood disorders, but the specific contributions of each region are unknown, including how they gate the impact of threat on decision making. To address this, the effects of GABAergic inactivation of these regions were studied in marmoset monkeys performing an instrumental approach–avoidance decision-making task that is sensitive to changes in anxiety. Inactivation of either region induced a negative bias away from punishment that could be ameliorated with anxiolytic treatment. However, whereas the effects of ventrolateral prefrontal cortex inactivation on punishment avoidance were seen immediately, those of orbitofrontal cortex inactivation were delayed and their expression was dependent upon an amygdala–anterior hippocampal circuit. We propose that these negative biases result from deficits in attentional control and punishment prediction, respectively, and that they provide the basis for understanding how distinct regional prefrontal dysregulation contributes to the heterogeneity of anxiety disorders with implications for cognitive-behavioral treatment strategies. Significance Fear of negative outcomes has a powerful adverse influence on decision making in anxiety disorders. Although neuroimaging studies of patients with anxiety disorders have revealed dysregulation in numerous frontal brain regions including the orbitofrontal and ventrolateral prefrontal cortex, the causal involvement of this dysregulation is unknown. Here we demonstrate that in the marmoset monkey, inactivation of anterior orbitofrontal or ventrolateral prefrontal cortex increases negative bias in decision making via two distinct cognitive mechanisms—elevated uncertainty and attentional disruption, respectively. These findings provide, to our knowledge, the first direct evidence that dysregulation of distinct neurocognitive mechanisms within the prefrontal cortex may underlie the mixed etiology of anxiety disorders. Such insight will allow the development of more precise diagnostics and individually tailored therapeutic approaches.