Evidence from psychopharmacological functional neuroimaging begins to elucidate the neurochemical mechanisms of cognitive control. Here the role of dopamine in two subcomponent processes of cognitive control is discussed: the active maintenance and the flexible updating of goal-relevant representations. A range of studies have highlighted a role for the prefrontal cortex (pFC) and its modulation by dopamine in the active maintenance of distractor-resistant goal-relevant representations. This work suggests that dopamine might modulate top-down signals from the pFC, thereby increasing the activity of posterior cortical regions that process goalrelevant representations and rendering them distractor-resistant. Conversely, other studies highlight a role for dopamine in the basal ganglia in cognitive switching, which might reflect a modulation of the selective gating of cortical cognitive and motor programs. We present a working hypothesis that integrates these two disparate literatures and states that the flexible adaptation of current goal-relevant representations is mediated by modulatory influences of activity in the dopamine-sensitive basal ganglia on connectivity between the prefrontal cortex and posterior cortex.
Keywords: Working memory, task-switching, pharmacological fMRI, Parkinson's disease
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