Disrupted effective connectivity of the periaqueductal gray in migraine without aura patients

Background: The periaqueductal gray (PAG) is a key region in the descending pain modulatory system. We applied a Granger causality analysis (GCA) based approach to examine resting-state effective connectivity (RSEC) of the bilateral PAG regions in migraine patients without aura (MwoA). Methods: : Resting-state fMRI data were obtained from 28 MwoA patients and 17 well-matched healthy controls (HCs). The RSEC of the bilateral PAG was characterized using a voxel-wised GCA method. The resulting RSEC measurements were assessed for correlations with other clinical features. Results: : Compared with the HCs, MwoA patients showed increased EC from left PAG to left anterior cingulate gyrus and right postcentral gyrus. Meanwhile, MwoA patients also showed increased EC from right PAG to left precentral gyrus and increased RSEC from left caudate and right middle occipital gyrus to right PAG. Conclusions: : Disturbances of RSEC between PAG and limbic system, primary sensorimotor cortex, and visual cortex may play a key role in neuropathological features, perception, and affection of MwoA. The current study provides further insights into the complex scenario of MwoA mechanisms.