Reduced fractional anisotropy of corpus callosum modulates inter-hemispheric resting state functional connectivity in migraine patients without aura

Abstract

Background: Diffusion tensor imaging (DTI) study revealed reduced fractional anisotropy (FA) values in the corpus callosum (CC) in migraine patients without aura. Abnormalities in white matter integrity, particularly in the CC, may affect inter-hemispheric resting state functional connectivity (RSFC). Unfortunately, relatively little is known about the alterations in functional interactions between the cerebral hemispheres during resting state in migraine patients without aura, and even less about how the inter-hemispheric RSFC are affected by the abnormalities of the CC.

Methods and findings: Twenty-one migraine patients without aura and 21 healthy controls participated in this study, age-, sex-, and education-matched. Tract-based spatial statistics (TBSS) was employed to investigate the white matter alterations of the CC. Meanwhile, voxel-mirrored homotopic connectivity (VMHC) was used to compare the inter-hemispheric RSFC differences between the patients and controls. TBSS analysis revealed reduced FA values in the genu and the splenium of CC in patient group. VMHC analysis showed decreased inter-hemispheric RSFC of anterior cingulate cortex (ACC) in migraine patients without aura relative to that of the controls. Furthermore, in migraine patients without aura, the reduced FA values of the genu of CC correlated with the decreased inter-hemispheric RSFC of the ACC.

Conclusions: Our findings demonstrated that the migraine patients without aura showed reduced FA values of the genu of CC and decreased inter-hemispheric RSFC of the ACC. The correlation between the above structural and functional changes suggested that the reduced fractional anisotropy (FA) of CC modulates inter-hemispheric VMHC in migraine patients without aura. Our results demonstrated that the VMHC alterations of ACC can reflect the FA changes of the genu of CC in migraine patients without aura.

Figure 1. White matter abnormalities of the corpus callosum (CC) in migraine patients.

a). Tract-based spatial statistics (TBSS) analysis revealed decreased fractional anisotropy (FA) values in the genu and the splenium of CC among patient group. b). the decreased FA values of the genu of CC were negatively correlated with duration of disease in migraine patients without aura.

Figure 2. Voxel-mirrored homotopic connectivity (VMHC) analysis results between migraine patients and healthy controls.

a). Resting state analysis revealed the reduced VMHC value of the ACC in migraine patients without aura. The VMHC value of the anterior cingulate cortex (ACC) was correlated with duration of migraine. b). The bilateral ACC were chosen as the region of interest (ROI) for subsequent seeding-based resting state functional connectivity (RSFC).

Figure 3. Functional connectivity analysis results between migraine patients and healthy controls.

a). Relative to healthy controls, migraine patients without aura showed increased RSFC between the left anterior cingulate cortex (ACC) and the left dorsolateral prefrontal cortex (DLPFC) and right orbitofrontal cortex (OFC) (Figure3. a). With regards to the right ACC, the migraine patients without aura showed increased RSFC in the bilateral OFC.

Figure 4. Functional and structural relationship analysis results in migraine patients.

a). The demonstration of the methods in this study. b). The reduced voxel-mirrored homotopic connectivity (VMHC) value of the anterior cingulate cortex (ACC) was significant correlated with the decreased fractional anisotropy (FA) value of the genu of orpus callosum (CC) in migraine patients without aura.