CALCA and migraine disorder: CGRP is widely distributed in the trigeminovascular system (Lennerz et al., 2008, Eftekhari and Edvinsson, 2011, Bhatt et al., 2014, Eftekhari et al., 2015, Miller et al., 2016) including the spinal trigeminal nucleus caudalis (SpVc)–a nucleus heavily implicated in central mechanisms of migraine (Moskowitz, 1990, Goadsby et al., 1991, Kaube et al., 1993, Cutrer et al., 1995, Burstein et al., 2004, Burstein and Jakubowski, 2010, Iyengar et al., 2017, Lukács et al., 2017).