Details

Autor(en) / Beteiligte

• Farries, Michael A.
• Faust, Thomas W.
• Mohebi, Ali
• Berke, Joshua D.

Titel

Selective encoding of reward predictions and prediction errors by globus pallidus subpopulations

Ist Teil von

• Current biology, 2023-10, Vol.33 (19), p.4124-4135.e5

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

2023

Quelle

ScienceDirect

Beschreibungen/Notizen

• Basal ganglia (BG) circuits help guide and invigorate actions using predictions of future rewards (values). Within the BG, the globus pallidus pars externa (GPe) may play an essential role in aggregating and distributing value information. We recorded from the GPe in unrestrained rats performing both Pavlovian and instrumental tasks to obtain rewards and distinguished neuronal subtypes by their firing properties across the wake/sleep cycle and optogenetic tagging. In both tasks, the parvalbumin-positive (PV+), faster-firing “prototypical” neurons showed strong, sustained modulation by value, unlike other subtypes, including the “arkypallidal” cells that project back to striatum. Furthermore, we discovered that a distinct minority (7%) of GP cells display slower, pacemaker-like firing and encode reward prediction errors (RPEs) almost identically to midbrain dopamine neurons. These cell-specific forms of GPe value representation help define the circuit mechanisms by which the BG contribute to motivation and reinforcement learning. •4 GPe cell types can be identified from activity during wakefulness and SWS•20%–50% of PV+ GPe neurons encode reward expectations across multiple tasks•A novel GPe cell type encodes RPE exactly like midbrain dopamine cells do Farries et al. show that a major GPe cell type, previously assumed to relay motor commands, encodes reward predictions. They also report a GPe cell type that behaves remarkably like midbrain dopamine cells, including encoding reward prediction errors (RPEs). The GPe provides a second source of RPE that could be used to guide learning.