Structural and functional brain alterations associated with pain in Parkinson's disease

Pain is a common non-motor symptom in Parkinson's disease (PD), but its neural basis remains unclear. This study included 65 PD patients with pain (PDP), 55 without pain (nPDP), and 35 healthy controls (HC), who underwent structural, functional, and diffusion MRI. Both PD groups showed reduced local gyrification index (LGI) in the left anterior insula (aINS) and decreased degree centrality (DC) in the left superior temporal gyrus/temporoparietal junction (STG/TPJ), with greater reductions in PDP. Fractional anisotropy (FA) was reduced in the ventral tegmental area/substantia nigra and bilateral caudate in both PD groups. Functional connectivity between the aINS and STG/TPJ was also reduced. In PDP patients, LGI and FA correlated negatively with pain intensity and positively with each other. These findings may enhance our understanding of the neural mechanisms underlying pain in PD and offer mechanistic insights that could inform the development of more targeted interventions for pain management in this population.