Fig. 4

Transcranial optoRET activation in a mouse brain using a blue LED home cage lid. a Schematic diagram of the experimental scheme for optoRET activation in vivo. b Representative immunohistochemistry images of the SNc regions of mice expressing optoRET, with (Light group) or without (Dark group) LED illumination. Scale bars = 200 and 50 µm (cropped image). c Comparison of pS6-positive TH-stained cell counts in the SNc region of mice between Dark (n = 3) and Light (n = 6) groups. Data are presented as means ± SEM (*p < 0.05; Kolmogorov–Smirnov test). d Representative images of immunoblots for pERK1/2 and GAPDH. Protein samples were prepared separately for the virus-injected (ipsilateral) side (Ipsi.) and un-injected (contralateral) side (Cont.) of mice expressing optoRET. e Comparison of pERK1/2 protein levels between Dark (n = 6) and Light (n = 7) groups. pERK1/2 protein levels are expressed as ipsilateral relative to contralateral (pERK1/2/GAPDH), and data are presented as means ± SEM (*p < 0.05; Kolmogorov–Smirnov test)