Dysfunctional Dynamics Seen in Pain Pathways in Migraine
Altered interictal connectivity levels decrease pain modulation
MONDAY, Dec. 12 (HealthDay News) -- Patients with migraines have an interictal increase in resting state intrinsic connectivity between the periaqueductal gray matter (PAG) and both nociceptive and sensory processing pathways, according to a study published online Dec. 7 in the Annals of Neurology.
Caterina Mainero, M.D., Ph.D., from Harvard Medical School in Charlestown, Mass., and colleagues examined functional connectivity of the PAG in migraine. Seventeen individuals with migraine (during a pain-free state) and 17 gender- and age-matched controls underwent resting-state functional magnetic resonance imaging to compare functional connectivity between PAG and a subset of brain areas involved in nociceptive/somatosensory processing and pain modulation. The correlation between the average monthly frequency of migraine attacks, as well as allodynia and intrinsic resting-state correlations within PAG networks, were evaluated.
The investigators found that, compared with controls, patients with migraine had stronger connectivity between the PAG and several brain areas within the nociceptive and somatosensory processing pathways. The strength of the connectivity in some areas within these pathways increased with increasing monthly frequency of migraine attacks. There was a significant reduction in functional resting-state connectivity between the PAG and brain regions with a predominant role in pain modulation. Compared with patients without allodynia, those with a history of allodynia had significantly lower connectivity between the PAG, prefrontal regions, and anterior cingulate.
"These data reveal interictal dysfunctional dynamics within pain pathways in migraine manifested as an impairment of the descending pain modulatory circuits, likely leading to loss of pain inhibition, and hyperexcitability primarily in nociceptive areas," the authors write.