Figure 3.

M1 inactivation experiment. A, A widefield fluorescence image of a whole brain extracted from a PV-Cre mouse injected with AAV2-1-EF1A-DIO-hChR2-eYFP in the motor cortex (M1). Black dotted lines indicate the boundary of ChR2-eYFP expression. Red dotted lines indicate the thinned skull areas over M1. B, A coronal slice near the forelimb region of M1 from a PV-Cre mouse injected with AAV2-1-EF1A-DIO-hChR2-eYFP (left) and a magnified view (right). PV⁺ neurons are labeled with red fluorophore from a PV antibody staining. ChR2⁺ neurons express eYFP. Most ChR2-expressing neurons are PV⁺. C, Inactivation experiment setup. LED light is placed over the headbar bilaterally in control sessions, or over M1 in inactivation sessions. Each mouse performed 5 control and 5 inactivation sessions (1 session/day).