to visualize GFP contained in D2 MSNs whereas a 568 nm filter was used to detect the presence of tdTomato into D1 MSNs. Each neurons being injected was carefully inspected with both filters in order to determine content in GFP and/or tdTomato with a 40X water immersion objective (NA 0.80). All injected MSNs were located in the dorsal striatal region, at the commissural level, and restricted to 0.02–0.26 mm in the anteroposterior axis relative to the bregma, 1–3 mm in the mediolateral axis and 2–3 mm in the dorsoventral axis, according to the stereotaxic mouse brain atlas70.
