Pain-Related Abnormal Neuronal Synchronization of the Nucleus Accumbens in Parkinson's Disease

Patients with Parkinson's disease (PD) often experience pain, which fluctuates in on and off states, but the underlying mechanism is unclear. The nucleus accumbens (NAc) is a central component of the mesolimbic dopaminergic pathway involved in pain processing. We conducted resting-state functional magnetic resonance imaging (rsfMRI) analysis to explore the relationship between the neuronal synchronization of NAc with pain-related brain regions and pain intensity in on and off states. We assessed 23 patients with sporadic PD based on rsfMRI and pain intensity using the revised Short-Form McGill Pain Questionnaire. Patients with PD displayed higher pain intensity scores in the off state than in the on state. The pain intensity in the off state was substantially correlated with the functional connectivity (FC) between the NAc and primary motor/sensory cortices and contralateral NAc. Changes in pain intensity from the on to off state displayed correlations with those between the right (rNA) and left NAc (lNAc) and the right precentral gyrus (rPreCG) /right insular cortex (rIC) from the off to on state. Aberrant bilateral NAc and rNAc-rPreCG/rIC FC in the off state were closely related to pain symptoms developed from the on to off states. These results suggest that the NAc in the mesolimbic pathway is related to pain in PD and may help understand the mechanism of pain development in patients with PD.

Automated summary

The study found that pain intensity in patients with Parkinson's disease fluctuates between on and off states, with a correlation to the functional connectivity of the nucleus accumbens (NAc) with pain-related brain regions. These results contribute to understanding the mechanism of pain development in PD patients.