ABSTRACT
Objective To investigate insula cortex activation evoked by stimulating different acupoints of lower extremity.Methods Twenty healthy male right-handed subjects were recruited to receive functional magnetic resonance imaging(fMRI)examination with a whole-body 3T Siemens Trio system for whole-brain imaging.Participants were at rest during scanning and were instructed to relax with their eyes closed,without falling asleep.A blockdesigned method was applied for acupoint stimulation.The examined acupoints on the right lower extremity were stimulated,respectively,resulting in 4 experimental conditions.Stimulation was performed by brushing the subject's skin over each acupoint with a sponge at a frequency of approximately 2 Hz.Images were analyzed using SPM5 software package.Group analysis was performed with the mixed-effects model.Small volume correction was used to investigate insula cortex activation under each condition at a threshold of P ＜ O.01,with a 6-mm radius centered on the local maxima of activation in insula cortex.The scope of insula cortex was determined with SPM anatomy toolbox.Results All the examined acupoints induced activation in contralateral insula cortex.Activation clusters evoked by different acupoints presented various types of locations and shapes,and all of them located in the posterior part of insula cortex.Activation in the ipsilateral insula cortex was not found for all examined acupoints.Conclusions Stimulating lower extremity acupoints can activate posterior insula cortex.This effect may promote the recovery of dysphagia via several mechanisms including facilitating the initiation of swallowing,improving oral and pharyngeal sensation,and reducing taste disturbance.