A thalamocorticostriatal dopamine network for psychostimulant-enhanced human cognitive flexibility.

Samanez-Larkin GR, Buckholtz JW, Cowan RL, Woodward ND, Li R, Ansari MS, Arrington CM, Baldwin RM, Smith CE, Treadway MT, Kessler RM, Zald DH
Biol Psychiatry. 2013 74 (2): 99-105

PMID: 23273721 · PMCID: PMC3615042 · DOI:10.1016/j.biopsych.2012.10.032

BACKGROUND - Everyday life demands continuous flexibility in thought and behavior. We examined whether individual differences in dopamine function are related to variability in the effects of amphetamine on one aspect of flexibility: task switching.

METHODS - Forty healthy human participants performed a task-switching paradigm following placebo and oral amphetamine administration. [(18)F]fallypride was used to measure D2/D3 baseline receptor availability and amphetamine-stimulated dopamine release.

RESULTS - The majority of the participants showed amphetamine-induced benefits through reductions in switch costs. However, such benefits were variable. Individuals with higher baseline thalamic and cortical receptor availability and striatal dopamine release showed greater reductions in switch costs following amphetamine than individuals with lower levels. The relationship between dopamine receptors and stimulant-enhanced flexibility was partially mediated by striatal dopamine release.

CONCLUSIONS - These data indicate that the impact of the psychostimulant on cognitive flexibility is influenced by the status of dopamine within a thalamocorticostriatal network. Beyond demonstrating a link between this dopaminergic network and the enhancement in task switching, these neural measures accounted for unique variance in predicting the psychostimulant-induced cognitive enhancement. These results suggest that there may be measurable aspects of variability in the dopamine system that predispose certain individuals to benefit from and hence use psychostimulants for cognitive enhancement.

Copyright © 2013 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

MeSH Terms (18)

Adaptation, Psychological Adolescent Adult Benzamides Cerebral Cortex Cognition Corpus Striatum Dextroamphetamine Dopamine Dopamine Antagonists Female Humans Male Nerve Net Pyrrolidines Radionuclide Imaging Thalamus Young Adult

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