Scientists at the University of Copenhagen have demonstrated that the trigeminal nerve, a cranial nerve whose activation underlies migraine pain, has direct access to cerebrospinal fluid (CSF) transported by the glymph system. Furthermore, in the run-up to a migraine, levels of multiple proteins in the CSF changed. One of them was calcitonin gene-related peptide (CGRP), a driver of migraine pain and target of several approved drugs for both treatment and prevention of migraine.