PV-PV mice exhibit distinct arena behavior following the 4-wk protocol (Post). PV-PV mice (n = 15, white bars) scored higher for total distance traveled, mean speed, and total time immobile and had fewer immobile periods than mice from the PV-Arch (n = 34, black bars), PV-ChR2 (n = 27, gray bars), and no-laser (n = 25, cross-hatched bars) groups. Error bars indicate SEM. *P < 0.05; **P < 0.01; ***P < 0.001.