A mismatch between striatal cholinergic pauses and dopaminergic reward prediction errors

Abstract

Striatal acetylcholine and dopamine critically regulate movement, motivation, and reward-related learning. Pauses in cholinergic interneuron (CIN) firing are thought to coincide with dopamine pulses encoding reward prediction errors (RPE) to jointly enable synaptic plasticity. Here, we examine the firing of identified CINs during reward-guided decision-making in freely moving rats and compare this firing to dopamine release. Relationships between CINs, dopamine, and behavior varied strongly by subregion. In the dorsal–lateral striatum, a Go! cue evoked burst–pause CIN spiking, followed by a brief dopamine pulse that was unrelated to RPE. In the dorsal–medial striatum, this cue evoked only a CIN pause, that was curtailed by a movement-selective rebound in firing. Finally, in the ventral striatum, a reward cue evoked RPE-coding increases in both dopamine and CIN firing, without a consistent pause. Our results demonstrate a spatial and temporal dissociation between CIN pauses and dopamine RPE signals and will inform future models of striatal information processing under both normal and pathological conditions.