Distinct Structural and Functional Heterogeneity of Dopamine Synapses in the Brain

Abstract

Dopamine system is a group of midbrain nuclei and their axonal projections across the entire brain. This system is essential for governing diverse neural functions, including voluntary movement, reward, motivation, mood, attention, learning, and memory. Although the role of neurotransmitter dopamine and dopamine neurons have been intensively studied so far, the precise structure and function of dopaminergic synapses remain unclear in various regions of the brain where dopaminergic axons differentially project. Here, we utilized enhanced confocal imaging and electrophysiology combined with optogenetics to dissect structural and functional heterogeneity of dopamine synapses across the brain. We found that dopaminergic synapses have regional heterogeneity in their distribution and spatial pattern. In addition, these structural features in dopamine synapses were correlated with functional aspects of dopaminergic synaptic transmission in different brain regions. Thus, the differential structure and function of dopamine synapses in distinct brain areas may contribute to the multi-faceted role of dopamine system in a variety of dopamine-related behaviors.