Fig. S8.

The dopamine-containing neurons of the striosome–dendron bouquets and of the posterior cell cluster project to the dorsal striatum. (A–C, G–I, and M–O) Transverse hemisection through the left striatum of three DAT-Cre mice that received intrastriatal injections of AAV9 carrying CAG-Flex-GCaMP6m. Anti-GCaMP6 immunoreactivity with anti-GFP antibody (shown in brown) shows dopamine-containing axons in the striatum, which originated from DAT-Cre-positive neurons that were retrogradely infected by AAV9. (D–F, J–L, and P–R) Cell bodies and dopamine-containing dendrons of retrogradely infected DAT-Cre-positive neurons are visible in transverse hemisections through the SN of the mice (D, E, J, K, P, and Q), as well as a posterior cell cluster (F, L, and R); n = 20 sections from 6 animals. The GCaMP6 expression is Cre-dependent and therefore is restricted to DAT-Cre–positive nigral neurons that project to the site of viral injection in the dorsal striatum. The intrastriatal viral injections targeted different districts; see Materials and Methods for injection coordinates.