This document includes supplementary figures and analyses related to the study.

<p>S1 Fig shows a schematic representation of the pAAV-CMV-IRES-EGFP-Opto-mGluR6 vector, demonstrating the cloning of the Opto-mGluR6 gene using EcoRI and XhoI restriction enzymes. S2 Fig presents the Ramachandran plot analysis of the wild-type opto-mGluR6 model, highlighting favored and allowed regions. S3 Fig includes multiple sequence alignments of melanopsins, rhodopsin, and other opsins, focusing on amino acids involved in retinal binding and absorption shifts. S4 Fig provides RNA secondary structures of Opto-mGluR6 and related constructs ROM19, ROM18, and ROM17. S5 Fig displays an immunoblot for GIRK channel expression in HEK-GIRK cells, while S6 Fig shows the light response of these cells, transiently transfected with pAAV-CMV-IRES-EGFP, under different light stimulations in a whole-cell voltage clamp. S1 Table shows RNA minimum free energy prediction for optogenetic constructs.</p> <p>(DOCX)</p>