CatWalk gait analysis was used to evaluate motor performance during normal gait 4 weeks after the stimulation paradigm described above. (A) Schematic of the CatWalk apparatus. Experimental mice walk through a long, narrow corridor on a touch-sensitive glass platform, under which a digital camera records paw print contours, allowing for software-guided reconstruction and analysis of gait. LF, left forepaw; LH, left hindpaw; RF, right forepaw; RH, right hindpaw. (B) Interlimb forelimb swing speed (in centimeters per second) difference of left forelimb minus right forelimb (n = 5 Thy1::ChR2 and 9 WT; n = 6 TSA-treated Thy1::ChR2 and 5 TSA-treated WT). (C and D) No alterations to paw pressure (C) or stride length (D) were observed in optogenetically stimulated Thy1::ChR2 mice or their WT littermate controls. The same is true in animals treated with the histone deacetylase inhibitor TSA (C and D). Untreated: n = 5 Thy1::ChR2 mice and 9 WT mice; TSA-treated: n = 4 Thy1::ChR2 mice and 5 WT mice. n.s. denotes P > 0.05. *P < 0.05. Error bars indicate SEM. AU, arbitrary units.