Alteration in functional connectivity of SC_thalamus with primary trigeminal neuralgia

Background Primary trigeminal neuralgia (PTN) is a recurrent condition of electric shock-like pain occurring in the facial area nervated by the sensory portion of the trigeminal nerve. The thalamus is a relay station for transmitting sensory information transmission, where the facial pain signal involved in PTN transmits. The multiple functions of the thalamus vary from its subregions, and changes in the functional connectivity (FC) between the thalamic sensory subregions and the whole brain are yet unclear. This study aims to explore the altered FC of thalamic sensory subregions in PTN patients using the resting-state functional magnetic resonance imaging (rs-fMRI). Methods Differences in the FC of the thalamic subregions with the whole brain voxels between 48 PTN patients and 35 age-matched healthy controls (HCs) were examined. Moreover, the correlation of altered FC in the brain regions with the course of PTN was identifed. Results Compared with HCs, PTN patients displayed a significantly increased FC between the SC_thalamus and postcentral gyrus, increased FC between the SC_thalamus and midfrontal gyrus, and decreased FC between the SC_thalamus and right supramarginal gyrus. The FC between the SC_thalamus and left postcentral gyrus ( r  = 0.442, P  = 0.002) and that between the SC_thalamus and right postcentral gyrus ( r  = 0.415, P  = 0.003) were positively correlated with the course of PTN. The FC between the SC_thalamus and right supramarginal gyrus ( r =-0.398, P  = 0.005) was negatively correlated with the course of PTN. Conclusion FC between the SC_thalamus and certain brain regions alters in PTN patients. The pathophysiological basis of the central mechanism changes in PTN patients at the subnuclear level provides a theoretical basis for developing new treatment methods for PTN.