ALTERED CAUDATE FUNCTIONAL CONNECTIVITY AND MICROSTRUCTURAL INTEGRITY IN CENTRAL POST-STROKE PAIN: A FUNCTIONAL AND DIFFUSION TENSOR IMAGING STUDY

Central post stroke pain (CPSP) is a common consequence of somatosensory stroke, typically occurring within 3-6 months after stroke, providing a unique window of opportunity to identify patients at risk and initiate treatment. However, predictive biomarkers are lacking. We aimed to identify longitudinal, brain-wide functional connectivity (FC) patterns and microstructural alterations preceding and following CPSP onset. 75 stroke patients were recruited within 10 days of stroke onset and followed for one year. We compared 26 patients who developed CPSP with 49 non-pain sensory stroke (NPSS) controls using resting-state fMRI and diffusion tensor imaging (DTI). Seed-based FC and voxel-based analyses were performed at the acute stage (<10 days post-stroke, “before pain”) and chronic stage (>60 days, “with pain”). Before pain onset, compared to NPSS patients, CPSP patients exhibited decreased FC between contralesional caudate (seed) and ipsilesional supplementary motor area (SMA) and pre-supplementary motor area. In the chronic stage with pain, CPSP patients showed persistently decreased FC between the contralesional caudate (seed) and ipsilesional SMA and precentral gyrus. DTI analyses revealed increased mean diffusivity, axial diffusivity, and radial diffusivity in the bilateral caudate nucleus in CPSP patients versus NPSS patients both before and after pain onset. Early disruption of caudate-centered functional connectivity and microstructural integrity precedes CPSP development and persists after pain onset. These multimodal neuroimaging markers may serve as predictive biomarkers for CPSP and suggest novel targets for early prevention and therapeutic intervention.