Brain anatomy changes associated with persistent neuropathic pain following spinal cord injury.

Persistent neuropathic pain commonly occurs following spinal cord injury (SCI). It remains one of the most challenging management problems in this condition. In order to develop more effective treatments, a better understanding of the neural changes associated with neuropathic SCI pain is required. The aim of this investigation was to use diffusion tensor imaging (DTI) to determine if persistent neuropathic pain following SCI is associated with changes in regional brain anatomy and connectivity. In 23 subjects with complete thoracic SCI, 12 with below-level neuropathic pain and 11 without pain, and 45 healthy control subjects, a series of whole-brain DTI scans were performed. The mean diffusivity (MD) of each voxel was calculated and values compared between groups. This analysis revealed that neuropathic pain following SCI is associated with significant differences in regional brain anatomy. These anatomical changes were located in pain-related regions as well as regions of the classic reward circuitry, that is, the nucleus accumbens and orbitofrontal, dorsolateral prefrontal, and posterior parietal cortices. The right posterior parietal cortex projected to most regions that displayed an anatomical change. Analysis of the fiber tracts connecting areas of MD differences revealed no significance differences in MD values between the SCI pain, SCI no pain, and control groups.