ABSTRACT
Objective: To investigate the impact of electrical stimulation numbness to central nervous system in normal people. Methods: Electric stimulator was used to establish low-frequency, high-frequency numbness models with 22 healthy subjects. Scores for numbness and emotional valence for different electrical stimulations were recorded, and data of functional MRI (fMRI) in task state were also collected. The differences of numbness and emotional valence score of subjects under low frequency and high frequency electrical stimulation were compared, respectively. Then brain regions with significant differences in brain activation intensity under different frequencies of electrical stimulation were obtained, and the differences of activation effect values of activated brain regions under different electrical stimulations intensity were compared, respectively. The relationship of numbness and emotional valence scores under high frequency electrical stimulation were analyzed. Results: There were statistical differences of numbness (t=13.18) and valence score (t=10.77) under different electrical stimulations (both P<0.05). There was negative correlation between numbness and valence scores under high-frequency electrical stimulation (r=-0.53, P=0.01). The brain areas with significant differences of activation intensity under different electrical stimulation included left parietal operculum, left middle cingulate gyrus, left temporal gyrus, right parietal operculum, left postcentral gyrus, right central operculum, right posterior insula and left thalamus (all P<0.05). Conclusion: The activated brain regions under different electrical stimulations caused numbness include left parietal operculum, left middle cingulate gyrus, left temporal gyrus, right parietal operculum, left postcentral gyrus, right central operculum, right posterior insula and left thalamus in normal people. Block-designed BOLD-fMRI can be used to detect activity of brain areas associated with numbness.