Multi-faceted role of dopamine afferents to the ventral pallidum in reward processing

Abstract

The ventral pallidum (VP) is necessary for reward processing and a key node in dopamine (DA) pathways. Yet the direct DA inputs have not been studied during reward learning. Here, we elucidate the role of VP DA in reward processing using circuit tracing, fibre photometry, and behavioural pharmacology in male rats. We show that VP receives both non-DA and DA inputs from the midbrain. During an instrumental reward conditioning paradigm, we characterized VP DA activity using a DA sensor (GRAB_DA1h) across learning, extinction, re-acquisition, and motivational test. Followed by pharmacological manipulation using the DA-antagonist (fluphenazine) in VP to demonstrate a causal role in reward learning and motivation. Together our findings advance the functional contributions of non-canonical mesolimbic DA pathways.