Brain dopamine (DA) has long been implicated in cognitive control processes, including
working memory. However, the precise role of DA in cognition is not well-understood,
partly because there is large variability in the response to dopaminergic drugs both
across different behaviors and across different individuals. We review evidence from
a series of studies with experimental animals, healthy humans, and patients with Parkinson's
disease, which highlight two important factors that contribute to this large variability.
First, the existence of an optimum DA level for cognitive function implicates the
need to take into account baseline levels of DA when isolating the effects of DA.
Second, cognitive control is a multifactorial phenomenon, requiring a dynamic balance
between cognitive stability and cognitive flexibility. These distinct components might
implicate the prefrontal cortex and the striatum, respectively. Manipulating DA will
thus have paradoxical consequences for distinct cognitive control processes, depending
on distinct basal or optimal levels of DA in different brain regions.
Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All