Fig. 7: Summary of findings.

Activity of D1 SPNs causes contraversive turning gait asymmetries via nigral disinhibition of the PnO → Chx10 Gi excitatory brainstem–spinal cord pathway^23,39,45. Loss of D1 SPN activity causes ipsiversive turning via nigral inhibition of the PnO → Chx10 Gi excitatory brainstem pathway^23,40,55.