Higher regional grey matter volume and white matter integrity in individuals with central neuropathic pain following spinal cord injury.

Spinal cord injury (SCI) is a debilitating neurological condition that often leads to central neuropathic pain (CNP). As the fundamental mechanism of CNP is not fully established, its management is one of the most challenging problems among people with SCI. In order to shed more light on CNP mechanisms, the aim of the current study was to compare the brain structure between individuals with SCI and CNP and those without CNP by examining the grey-matter volume and the white-matter integrity. Fifty-two individuals with SCI; 28 with CNP and 24 without CNP, underwent an MRI session, including a T1-weighted scan for voxel-based morphometry, and a diffusion-weighted imaging scan for white-matter integrity analysis, as measured by fractional anisotropy and mean diffusivity. We found significantly higher grey-matter volume in individuals with CNP compared to pain free individuals in the right superior (p<0.0014) and middle temporal gyri (p<0.0001). Moreover, individuals with CNP exhibited higher white-matter integrity in the splenium of the corpus callosum (p<0.0001) and in the posterior cingulum (p<0.0001), compared to pain free individuals. The results suggest that the existence of CNP following SCI is associated with grey-matter and white-matter structural abnormalities in regions involved in pain intensification and spread, and which may reflect maladaptive neural plasticity in CNP.