Activation in the Swallowing Network by task-based fMRI: a seed-based Functional Connectivity Study

Abstract

Background Task-based functional magnetic resonance imaging (fMRI) is an effective method for noninvasively studying brain activity. We aim to find representative brain areas of the swallowing movement and compare the functional connectivity differences in these areas. Methods A total of 23 participants were recruited to undergo task-based fMRI scans. Subject-level statistical analysis and group-level activation analysis were conducted using SPM12. Seed-based Functional Connectivity (FC) analyses were conducted to construct FC in brain level. We used the two-sample t-test to identify distinctive FC patterns in various seeds. The relationship between FC values and swallowing frequency was also explored. Results In experiment I, activation patterns were observed in swallowing-related brain regions in the 30-second saliva swallowing trial task, but not in 18s-on task at the group level. The peak voxels and coordinates of brain regions activated by saliva swallowing in experiment II were used as the seeds in resting-state fMRI FC analysis. Two sample t-tests showed that the seed located in right pericentral area (Seed3) had significantly more intensive FC than the seed located in cingulum (Seed5) in left postcentral gyrus, the seed located in left pericentral area(Seed4) had significantly more intensive FC than the seeds located in cerebellum(Seed1,Seed2) or in cingulum(Seed5) in right postcentral gyrus, Seed5 had significantly more intensive FC than Seed1,Seed2,Seed4 in right middle frontal gyrus, right superior frontal gyrus and left supplementary motor area separately. No significant positive or negative correlations between swallowing frequency and FC values were found based on Seed 3,4,5. Conclusions Saliva swallowing trail task with self-paced rhythm in sufficient time can activate the swallowing-related brain regions effectively. The activation peaks in the bilateral pericentral area are representative in the swallowing process and could be new therapeutic targets for poststroke dysphagia instead of traditional route. Trial registration number (TRN) ChiCTR2100054835; Date of registration: 28 December 2021. https://www.chictr.org.cn/