OBJECTIVE: Using whole-brain functional magnetic resonance imaging, we aimed to investigate abnormal spontaneous brain activity in the resting state of patients with trigeminal neuralgia (TN) and explore their relationship with pain symptoms and negative emotions. METHODS: This study included 46 patients with TN diagnosed at our hospital from December 2022 to June 2023 and 35 healthy controls. All patients with TN completed questionnaires related to pain and emotions. The data analysis compared amplitude of low-frequency fluctuation (ALFF) in the brain between TN and healthy control groups. Pearson correlation analysis was used to explore the intricate relationships between pain symptoms, negative emotions, and brain functional abnormalities in patients with TN. RESULTS: Compared with healthy controls, patients with TN exhibited significantly reduced ALFF in the left superior frontal gyrus (SFG), bilateral middle frontal gyrus, bilateral inferior frontal gyrus, right precentral gyrus, right superior temporal gyrus, bilateral middle temporal gyrus, left inferior temporal gyrus, and right cingulate gyrus (CG) (P <
0.05). In correlation analysis, ALFF in the left SFG and right CG was negatively correlated with pain symptoms and negative emotions in patients with TN. CONCLUSIONS: Patients with TN show functional abnormalities in several key brain regions that are involved in pain perception and emotion regulation. These abnormalities primarily manifest as a reduction in spontaneous neural activity. ALFF in the left SFG and right CG is negatively correlated with the severity of pain and negative emotions, indicating that as pain and negative emotions become more severe in patients with TN, neural activity decreases more significantly in specific brain regions. This suggests that the left SFG and right CG may be characteristic brain regions in the pathophysiological mechanism of TN.