Cerebral lesion correlates of sympathetic cardiovascular activation in multiple sclerosis

Figures

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  Figure 1. Process of lesion delineation and spatial normalization. (a) T2‐weighted MR images in original space. (b) The T2‐weighted axial image was used to define the area of T2‐hyperintense MS‐lesions shown as a red contour and below the red lesion shape. (c) The lesion shape, the T2‐weighted as well as the T1‐weighted MRI scans were then transformed into stereotaxic space which generated the normalized map. The normalized lesion map was also applied to the normalized T1‐weighted brain to qualitatively demonstrate the accuracy of image normalization [Color figure can be viewed at http://wileyonlinelibrary.com]

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  Figure 2. Overlap and distribution of T2‐hyperintense multiple sclerosis lesions of all patients. The number of overlapping lesions is illustrated by different colors coding increasing frequencies from dark red to yellow. Regions with higher lesion overlap counts are found symmetrically in periventricular regions, most prominently in the parietal periventricular white matter, as well as in the subinsular regions, and periaqueductal midbrain gray. Montreal Neurological Institute (MNI) z‐coordinates of each transverse section are given. L, left hemisphere; N, number of individuals with a lesion in a given voxel; R, right hemisphere [Color figure can be viewed at http://wileyonlinelibrary.com]

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  Figure 3. Results of the voxel‐wise t‐test statistics comparing parameters of autonomic arousal between patients with and without lesions in a given voxel. Lesioned voxels in the left insular juxtacortical white matter, hippocampus (axial slices), and right inferior opercular juxtacortical region (coronal slice) were most prominently associated with a shift of cardiac sympatho‐vagal balance toward increased sympathetic modulation, as evidenced by increased LF/HF‐ratios of RR‐intervals. A false discovery rate (FDR) correction of q < 0.01 was applied (z‐score = 3.5). A smaller lesion cluster correlated also in the right middle cerebellar peduncle (a). Lesioned voxels most prominently in the right posterior parietal‐juxtacortical region, as well as in the left insular regions were associated with increased sympathetic blood pressure modulation, as shown by an increase of BPsys‐LF‐powers (z‐score = 3.6). Only voxels that were damaged in at least four individuals were included in the analysis. L, left hemisphere; R, right hemisphere; z = z‐score [Color figure can be viewed at http://wileyonlinelibrary.com]