Extended Data Fig. 4: Optogenetic stimulation of LH^Vglut2 neurons significantly augments walking after chronic SCI.

a, Schematic of the experimental scheme demonstrating injection of an AAV5-DIO-ChR2-YFP into the right-sided LH of Vglut2^Cre mice with insertion of an optic fiber. Mice underwent a left lateral hemisection at T10, and behavioral recordings were performed at 8 weeks post-SCI. Representative photomicrograph demonstrating ChR2 expression in LH^Vglut2 neurons following injections of AAV5-DIO-ChR2-YFP. The tract of the optic fiber is also visible in the LH, magnified in the inset. 3 V: third ventricle.Photomicrographs demonstrating cFos activation in the LH in response to 10 minutes of blue light stimulation in a Vglut2^Cre animal injected with AAV5-DIO-ChR2-YFP compared to a Vglut2^Cre mice injected with control virus. Quantification of cFos-positive cells revealed significantly more cFos^ON cells in mice injected with AAV5-DIO-ChR2-YFP compared to control virus (n = 5 mice per group; independent samples two-tailed t-test; t = 7.068; p = 0.0001). Lesion reconstructions of animals included in kinematic analysis are provided. b, Kinematic analysis of mice following optogenetic activation of LH^Vglut2 neurons. Walking was quantified using principal component analysis as described in Fig. 1c and Extended Data Fig. 1c (n ≥ 10 gait cycles per mouse, n = 5 mice per group). Statistics are provided in Supplementary Data 1. c, As in b, for mice following different frequencies of optogenetic stimulation (n ≥ 10 gait cycles per mouse, n = 5 mice per group). d, As in b, for mice following photostimulation and injections of AAVs expressing only the reporter protein GFP, with no opsin expression (n ≥ 10 gait cycles per mouse, n = 5 mice per group). Statistics are provided in Supplementary Data 1.