The following is the summary of “Longitudinal changes in functional connectivity and pain-induced brain activations in patients with migraine: a functional MRI study pre- and post- treatment with Erenumab” published in the December 2022 issue of Headache and Pain by Schwedt, et al.

A combination of central and peripheral nerve system mechanisms causes migraines. Anti-calcitonin gene-related peptide (CGRP) receptor monoclonal antibody erenumab helps prevent migraines despite having low central nervous system penetrance. The purpose of this research was to examine the relationship between erenumab responsiveness, functional connectivity changes, and pain-induced brain activations. Pre-treatment brain functional MRI (fMRI) included resting-state functional connectivity and BOLD measures in response to moderately painful heat stimulation to the forearm in adults who reported 6-25 migraine days per month during a 4-week headache diary run-in phase. 

After that, there were 2 sessions of erenumab therapy (at baseline and 4 weeks later) with 140 mg. About 2 weeks and 8 weeks after the initial erenumab treatment, fMRI was done. Resting-state functional connectivity and thermal pain-related brain activations were studied before and after therapy using a longitudinal Sandwich estimator study. Researchers  compared the fMRI results of people who responded to erenumab therapy with those of people who did not. About 32 patients had longitudinal imaging data from before therapy and after. Their mean age was 40.3 (+/− 13), with a standard deviation of 13. Headache frequency was 15.8 (+/- 4.4) per 28 days, and migraine frequency was 13.8 (+/- 4.7) per 28 days before therapy. Around 18 out of 32 patients responded to erenumab (56%). 

Post-treatment, erenumab responders differed from non-responders in 3 ways: pain-induced activations in the middle cingulate and posterior cingulate; region-to-region functional connectivity between several regions, including the temporal pole, supramarginal gyrus, and hypothalamus; and functional network connectivity among pain-processing regions, including higher global efficiency, clustering coefficient, node degree, regional efficiency, and modularity. In addition, changes in resting state functional connectivity and central processing of extracranial painful stimuli accompanied reductions in migraine day frequency with erenumab treatment, in contrast to erenumab non-responders.