Whole-Brain Mapping of Direct Inputs to Dopamine D1 and D2 Receptor-Expressing Medium Spiny Neurons in the Posterior Dorsomedial Striatum.

The posterior dorsomedial striatum (pDMS) is mainly composed of medium spiny neurons (MSNs) expressing either dopamine D1 receptors (D1Rs) or D2Rs. Activation of these two MSN types produces opposing effects on addictive behaviors. However, it remains unclear whether pDMS D1-MSNs or D2-MSNs receive afferent inputs from different brain regions or whether the extrastriatal afferents express distinct dopamine receptors.

Alcohol intake enhances glutamatergic transmission from D2 receptor-expressing afferents onto D1 receptor-expressing medium spiny neurons in the dorsomedial striatum.

Dopaminergic modulation of corticostriatal transmission is critically involved in reward-driven behaviors. This modulation is mainly mediated by dopamine D1 receptors (D1Rs) and D2Rs, which are highly expressed in medium spiny neurons (MSNs) of the dorsomedial striatum (DMS), a brain region essential for goal-directed behaviors and addiction. D1Rs and D2Rs are also present at presynaptic cortical terminals within the DMS.