Anatomical alterations of the visual motion processing network in migraine with and without aura

Abstract

Background: Patients suffering from migraine with aura (MWA) and migraine without aura (MWoA) show abnormalities in visual motion perception during and between attacks. Whether this represents the consequences of structural changes in motion-processing networks in migraineurs is unknown. Moreover, the diagnosis of migraine relies on patient's history, and finding differences in the brain of migraineurs might help to contribute to basic research aimed at better understanding the pathophysiology of migraine.

Methods and findings: To investigate a common potential anatomical basis for these disturbances, we used high-resolution cortical thickness measurement and diffusion tensor imaging (DTI) to examine the motion-processing network in 24 migraine patients (12 with MWA and 12 MWoA) and 15 age-matched healthy controls (HCs). We found increased cortical thickness of motion-processing visual areas MT+ and V3A in migraineurs compared to HCs. Cortical thickness increases were accompanied by abnormalities of the subjacent white matter. In addition, DTI revealed that migraineurs have alterations in superior colliculus and the lateral geniculate nucleus, which are also involved in visual processing.

Conclusions: A structural abnormality in the network of motion-processing areas could account for, or be the result of, the cortical hyperexcitability observed in migraineurs. The finding in patients with both MWA and MWoA of thickness abnormalities in area V3A, previously described as a source in spreading changes involved in visual aura, raises the question as to whether a "silent" cortical spreading depression develops as well in MWoA. In addition, these experimental data may provide clinicians and researchers with a noninvasively acquirable migraine biomarker.

Figure 1. Cortical Thickness Is Increased in Motion-Processing Areas in Migraineurs

Values are presented in mean millimeters (SD). V3A: MWA, 2.00 (0.09); MWoA, 2.06 (0.19); HCs, 1.86 (0.08). MT+: MWA, 2.11 (0.21); MWoA, 2.10 (0.88); HCs, 1.87 (0.17). Asterisks represent p-value summary * p < 0.05; ** p < 0.01

Figure 2. Retinotopic Localization of Cortical Thickness Changes

Flattened maps of the right occipital cortex, gyri, and sulci are indicated as light and dark gray. The borders of retinotopic areas are indicated in white (horizontal meridians, solid lines; upper vertical meridians, dotted lines; lower vertical meridians, dashed lines). The image on the left is taken from our previous data [29] and shows the progression of CSD during a visual aura, starting in area V3A, in a single participant. The image on the right shows the average map of the mean thickness difference of 24 migraineurs compared with 15 matched controls, projected on the same brain, with the superimposed retinotopy for one participant. A clear correspondence can be seen between the area of CSD origin in V3A in the left image and cortical thickness difference in the right image. In addition, areas of thickening can be observed in visual area MT+.

Figure 3. Fractional Anisotropy Differences in Migraineurs Versus Healthy Controls

Coronal (A) and sagittal (B) sections show the areas exhibiting statistically significant lower FA values in migraineurs compared to HCs. Significant differences can be seen in the WM underlying MT+ and V3A areas (A), in the superior colliculus (SC) (B), and in the left LGN (C).