Instead, we determined that melanopsin co-localizes with CGRP, a neuropeptide known to be expressed in small and medium (C fiber and Aδ fiber) TG neurons that modulate vascular caliber and nociception, with a role in migraine pathophysiology (Edvinsson et al., 1987; Felipe et al., 1999; Tajti et al., 1999; Hou et al., 2001; Eftekhari et al., 2010; Russo, 2015). This evidence concerns the gene OPN4 and migraine disorder.