Pharmacological modulation of dopamine D1 and D2 receptors reveals distinct neural networks related to probabilistic learning in non-human primates.

Abstract

The neurotransmitter dopamine (DA) has a multifaceted role in healthy and disordered brains through its action on multiple subtypes of dopaminergic receptors. How modulation of these receptors influences learning and motivation by altering intrinsic brain-wide networks remains unclear. Here we performed parallel behavioral and resting-state functional MRI experiments after administration of two different DA receptor antagonists in macaque monkeys. Systemic administration of SCH-23390 (D1 antagonist) slowed probabilistic learning when subjects had to learn new stimulus-reward associations and diminished functional connectivity (FC) in cortico-cortical and fronto-striatal connections. By contrast, haloperidol (D2 antagonist) improved learning and broadly enhanced FC in cortical connections. Further comparisons between the effect of SCH-23390/haloperidol on behavioral and resting-state FC revealed specific cortical and subcortical networks associated with the cognitive and motivational effects of DA manipulation, respectively. Thus, we reveal distinct brain-wide networks that are associated with the dopaminergic control of learning and motivation via DA receptors. Significance StatementD1 and D2 receptors are heavily implicated in cognitive and motivational processes, as well as in a number of psychiatric disorders. Despite this, little is known about how selective manipulation of these different receptors impacts cognition through changing activity across brain-wide intrinsic networks. Here, we examined the acute behavioral and brain-wide effects of D1 and D2 receptor-selective antagonists, SCH-23390 and haloperidol, in macaques performing a probabilistic learning task. SCH administration diminished, and haloperidol improved, animals task performance. Mirroring these effects on behavior, SCH reduced, and haloperidol increased, the resting-state functional connectivity across brain-wide networks, most notably in the cortico-striatal areas. Thus, our results highlight the opposing effects of D1 and D2 receptor modulation on the brain and behavior.