Abstract
BackgroundGranger causality analysis (GCA) has been used to investigate the pathophysiology of migraine. Amygdala plays a key role in pain modulation of migraine attack. However, the detailed neuromechanism remained to be elucidated. We applied GCA to explore the amygdala-based directional effective connectivity in migraine without aura (MwoA) and to determine the relation with clinical characteristics.MethodsForty-five MwoA patients and forty age-, sex-, and years of education-matched healthy controls(HCs) underwent resting-state functional magnetic resonance imaging (fMRI). Bilateral amygdala were used as seed regions in GCA to investigate directional effective connectivity and relation with migraine duration or attack frequency.ResultsMwoA patients showed significantly decreased effective connectivity from right amygdala to right superior temporal gyrus, left superior temporal gyrus and right precentral gyrus compared with HCs. Furthermore, MwoA patients demonstrated significantly decreased effective connectivity from the left amygdala to the ipsilateral superior temporal gyrus. Also, MwoA patients showed enhanced effective connectivity from left inferior frontal gyrus to left amygdala. Effective connectivity outflow from right amygdala to right precentral gyrus was negatively correlated to disease duration.ConclusionsAltered directional effective connectivity of amygdala demonstrated that neurolimbic pain networks contribute to multisensory integration abnormalities and deficits in pain modulation of MwoA patients.
Highlights
Migraine is a disabling primary headache disorder and was ranked third–highest cause of disability worldwide in both males and females under the age of 50 years[1]
The specific intrinsic brain effective connectivity among pain-related networks in migraine without aura (MwoA) patients are affected after long-term migraine attacks[13, 14]
Granger causality analysis MwoA patients showed significantly decreased effective connectivity from right amygdala to several brain regions that include right superior temporal gyrus, left superior temporal gyrus and right precentral gyrus compared with healthy controls (HCs) (Table 2; Fig. 1)
Summary
Migraine is a disabling primary headache disorder and was ranked third–highest cause of disability worldwide in both males and females under the age of 50 years[1]. Amygdala, which is a large grey matter complex in neurolimbic system, plays a key role in pain modulation during a migraine attack[4,5,6,7]. Seed-based whole-brain correlation method showed migraine patients have disrupted limbic system (amygdala and hippocampus) functional connectivity to pain-related cortex regions of modulatory and encoding[9]. Most of previous studies about the effective connectivity in neurolimbic system omit the directional influence of the cerebral functional cortex on amygdala. The specific intrinsic brain effective connectivity among pain-related networks in MwoA patients are affected after long-term migraine attacks[13, 14]. We applied GCA to explore the amygdala-based directional effective connectivity in migraine without aura (MwoA) and to determine the relation with clinical characteristics
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