| Objective:Repetitive transcranial magnetic stimulation(rTMS)is a non-invasive brain stimulation technology,which is widely used in the treatment of depression,Parkinson's disease,Alzheimer's disease and other diseases.The number and frequency of stimulation pulses can be combined into different transcranial magnetic stimulation patterns to achieve different therapeutic effects.However,due to the differences in therapeutic targets,stimulus sequences and other parameters,transcranial magnetic stimulation often generates different treatment effects.Therefore,the stability and reliability of transcranial magnetic stimulation are questioned.With the continuous development of neuroimaging science,it provides us with new means of observation.Functional magnetic resonance imaging(fMRI) is a new observation tool,which can clearly reveal the changes of brain network mechanism before and after stimulation with high spatial resolution.Compared with the previous studies on exploring the repeatability of transcranial magnetic stimulation from the perspective of motor evoked potentials(MEPs) and electroencephalogram(EEG),it can directly reflect the changes of brain network mechanism after transcranial magnetic stimulation intervention,which is more convincing.However,there is no repetitive studies using functional magnetic resonance imaging to explore transcranial magnetic stimulation imaging.At present,as an emerging non-invasive brain stimulation technology,the clinical application of transcranial magnetic stimulation is still in the stage of promotion,application and exploration.In order to better expand the use of repetitive transcranial magnetic stimulation,it is necessary to understand and verify the repeatability of brain function changes caused by transcranial magnetic stimulation on the cortex.Supplementary motor area(SMA) is an important node of the action network.Besides,it is also closely related to individual movement and response inhibition,and often serves as a target for the treatment of disorders related to movement.It is of great practical significance to study the repeatability of transcranial magnetic stimulation imaging with supplementary motor area as the stimulation target.This study aims to explore the changes of brain network mechanism of supplementary motor area stimulated by transcranial magnetic stimulation and the repeatability of imaging.experiment 1 : To reveal the changes of brain imaging mechanism caused by transcranial magnetic stimulation regulating supplementary motor area.The repeatability of TMS intervention was verified by the repeated effect of transcranial magnetic stimulation on supplementary motor area,so as to further verify the reliability of transcranial magnetic stimulation.experiment 2 : To explore the washout period of transcranial magnetic stimulation treatment,and verify whether there is a late effect after one week of transcranial magnetic stimulation stimulation based on study 1.Method:A total of 35 healthy male subjects were recruited for the study,of which 21 took part in experiment 1 and 14 in experiment 2.Experiment 1 used within-subjects design,subjects received two real stimulations and one sham stimulation in three separate mornings.The order of real and sham stimulation was random.Functional magnetic resonance imaging scanning was performed before and after each stimulation.The interval between each stimulation was one week or more.The repeatability of transcranial magnetic stimulation imaging was explored by comparing the functional connectivity(FC)of resting brain network and the change with amplitude of low fluctuation(ALFF)after two true stimulation.Experiment 2 used between-subjects design,which were divided into two groups: real stimulus group and sham stimulus group.The experimental data of the first TMS stimulation in Experiment 1 and the same interval of one week after the test were included in the experiment 2 into the analysis of the elution period of Experiment 2 to increase the sample size of Experiment 2.It is necessary to improve the validity of this experimental study with sufficient sample size.Functional connectivity and amplitude of low fluctuation of resting brain network before and after transcranial magnetic stimulation were compared to explore the washout period of cTBS(continue theta burst stimulation)sequence.Results:experiment 1: Compared with the baseline,functional connectivity of right cerebellum was enhanced after the first stimulation,and there was no difference before and after the second stimulation.Compared with the baseline,functional connectivity of paracentral lobule was enhanced after the sham stimulation.The results are corrected and verified by FWE(voxel,P<0.01,cluster,P<0.05).The right cerebellum was used as the region of interest(ROI)to extract the signal value of functional connectivity.It was found that there was significant difference between the real stimulation and the baseline(t=3.24,P<0.01;t=3.37,P<0.01),but no significant difference between baseline and the sham stimulation.And the paracentral lobule was used as the region of interest to extract the signal value of functional connectivity.It was found that there was no significant difference between two real stimulations.After the first real stimulation,the amplitude of low fluctuation of the right fusiform gyrus,cerebellum,and central posterior gyrus were significantly changed relative to the sham stimulus.After the second real stimulation,the amplitude of low fluctuation of the left cerebellum and the right insula compared to the sham stimulation increased significantly.By comparing the amplitude of low fluctuation difference between the real and sham stimulation,it was found that the two real stimulations both caused changes in the right insula.experiment 2: After the stimulation of supplementary motor area with continue theta burst stimulation for 1 week,the functional connectivity between region of interest and right insula was enhanced compared with baseline after functional connectivity analysis,but the false stimulus was not significant.The results are corrected and verified by FWE(voxel,P<0.01,cluster,P<0.05).The amplitude of low fluctuation values of rectus,orbital superior frontal gyrus,gyrus lingualis and middle temporal gyrus changed significantly,and the amplitude of low fluctuation values of the paracentral lobule and the left cuneus increased after false stimulus.Conclusion:Supplementary motor area regulated by transcranial magnetic stimulation has a good repeatability in imaging voxel,and a bad repeatability in imaging cluster.The therapeutic effect of supplementary motor area regulated by the continue theta burst stimulation sequence can last for more than 1 week. |
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