Affective Circuitry Alterations in Patients with Trigeminal Neuralgia

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Trigeminal neuralgia (TN) is a debilitating neuropathic facial pain disorder.
• Affect-related brain changes are common in chronic pain but understudied in TN.
• Key white matter tracts involved in affect regulation are the cingulum, fornix, and medial forebrain bundle.

Purpose of the Study:

• To investigate the impact of TN on the white matter microstructure of affect-related brain tracts.
• To examine gray matter volume changes in brain regions associated with these tracts.
• To compare brain structure in TN patients with healthy controls.

Main Methods:

• Diffusion magnetic resonance imaging (dMRI) and deterministic tractography were used to model white matter tracts.
• Volumetric gray matter analysis was performed on the hippocampus, cingulate cortex, nucleus accumbens, and ventral diencephalon.
• 37 TN patients and age/sex-matched healthy controls were included.

Main Results:

• White matter microstructure of the cingulum and medial forebrain bundle (MFB) was altered in TN patients.
• Specific dMRI metrics showed significant changes in the posterior cingulum and MFB-VTA (ventral tegmental area).
• Decreased gray matter volumes were observed in the hippocampus, posterior cingulate, nucleus accumbens, and ventral diencephalon.

Conclusions:

• TN is associated with selective alterations in brain affective circuits.
• These structural brain changes may underlie negative affect and mood/anxiety comorbidities in TN.
• Findings highlight the neural basis of affective disturbances in chronic neuropathic pain.