T1-/T2-weighted ratio reveals no alterations to gray matter myelination in temporal lobe epilepsy

Abstract

Short-range functional connectivity in the limbic network is increased in patients with temporal lobe epilepsy (TLE), and recent studies have shown that cortical myelin content correlates with fMRI connectivity. We thus hypothesized that myelin may increase progressively in the epileptic network. We compared T1w/T2w gray matter myelin maps between TLE patients and age-matched controls and assessed relationships between myelin and aging. While both TLE patients and healthy controls exhibited increased T1w/T2w intensity with age, we found no evidence for significant group-level aberrations in overall myelin content or myelin changes through time in TLE.

Figure 1

Results of one‐sample t‐tests showing a positive linear relationship between T1w/T2w intensity and age in TLE patients and controls. Only results from significant clusters after FWER correction to p < 0.05 are displayed at MNI z‐coordinates −5, 0, 5, 10, and 15. Findings suggest a lifetime increase in subcortical myelin. While the control group showed a slightly larger overall cluster extent, no significant differences between groups were present.

Figure 2

Box plots of SPM‐adjusted voxel data in the parahippocampal gyrus (MNI coordinates 30, −20, −22). Neither group shows a stronger tendency toward outliers, nor is there any significant difference in group variance.