GPe Projections to the Retrorubral Field Give Rise to Diverging GABAergic and DAergic Circuits

The external segment of the globus pallidus (GPe) is involved in the modulation of motor output and limbic components of behavior. The circuitry by which the GPe contributes to limbic components of behavior remains unknown. While many investigations have focused on the local circuitry within the basal ganglia, numerous GPe projections to target regions outside of the basal ganglia including the midbrain, thalamus, and cortex exist and remain largely unexplored. Here, by anatomical and electrophysiological means we investigate the projections of the GPe to the Retrorubral Field (RRF), a dopaminergic nucleus in the caudal midbrain, in both male and female mice. We find that the GPe targets both GABAergic and DAergic neurons in the RRF (RRF