Abnormal white matter microstructure in the amygdala-related fiber tract pathways in patients with trigeminal...

Trigeminal neuralgia (TN) is characterized by recurrent, severe facial pain often accompanied by negative emotional states such as anxiety and depression. However, the neurobiological mechanisms linking pain and emotion in TN remain unclear. In this cross-sectional study, we used diffusion tensor imaging (DTI) with seed-based fiber streamline analysis to examine amygdala-related white matter pathways in 46 TN patients and 35 age- and sex-matched healthy controls. Pain was quantified using the Penn Facial Pain Rating (PFPR) and the McGill Pain Questionnaire (MPQ), while emotional distress was assessed via the Pain Catastrophizing Scale (PCS) and the Pain Anxiety Symptom Scale (PASS). Compared with controls, TN patients exhibited significantly lower fractional anisotropy (FA) values (p < 0.05) and higher mean diffusivity in these fiber tracts, mainly located at the splenium of the corpus callosum, bilateral anterior corona radiata, and bilateral external capsule. Correlation analysis revealed that higher PCS scores were significantly associated with increased PFPR scores (r = 0.56, p < 0.001). Furthermore, mediation analysis demonstrated that abnormal FA in the amygdala-related fiber pathways partially mediated the relationship between negative emotions and facial pain intensity (direct effect: b = 0.475, p < 0.001; indirect effect: b = 0.084, p = 0.008). These results suggest that alterations in amygdala-related white matter microstructure may underlie the interplay between negative emotions and pain in TN, providing a potential neurobiological basis for future targeted interventions. PERSPECTIVE: This study suggests that pain catastrophizing may alter brain structure and contribute to chronic facial pain in trigeminal neuralgia patients. Early interventions targeting negative emotions could prevent further structural changes and improve clinical outcomes.