An Investigation Of The Possible Mechanisms Of RTMS Treat In Patients With Post-stroke Depression Based On Rs-fMRI

BackgroundPost stroke depression(PSD)refers to neuropsychiatric syndrome,which occurs after stroke events with depression and energy loss as the main clinical manifestations.Repetitive transcranial magnetic stimulation(rTMS)is a neuroregulatory technique that produces efficacy by enhancing or inhibiting cortical excitability.Restingstate functional magnetic resonance imaging(rs-f MRI)provides a new method for the study of neuropsychiatric diseases because of its non-invasive,easy to operate and high spatial-temporal resolution.The prefrontal-limbic system is an important loop of information transmission in the brain,participating in the process of emotional processing.The triple brain network model includes the default mode network(DMN),executive control network(ECN)and salience network(SN),and abnormalities in functional connectivity are associated with several neuropsychiatric disorders.ObjectiveThe purpose of this study was to observe the clinical efficacy of high frequency rTMS in the treatment of ischemic PSD and to explore the mechanism of its nervous system by using rs-f MRI techniques.MethodsA total of 37 patients with PSD in our hospital were included and randomly divided into 18 in the treatment group and 19 in the control group.Both groups received standardized treatment according to the clinical guidelines for ischemic stroke,and the treatment group was given 20 sessions of rTMS on this basis.The rs-f MRI data collection and Hamilton Depression Scale(HAMD)evaluation were completed at two time points before and after rTMS treatment.The regional homogeneity(Re Ho)and amplitude of low frequency /fractional amplitude of frequency fluctuation(ALFF/f ALFF)were obtained by analyzing the rs-f MRI data.The Region-of-Interest(ROI)was defined as the left dorsolateral anterior frontal lobe,left anterior cingulate gyrus,and left amygdala.The functional connection between the ROI and the whole brain was calculated(functional connectivity,FC).Using paired sample t-test to compare the HAMD scale scores and neuroimaging index between the pre-treatment and post-treatment groups;Using two independent samples t-test between the two groups after treatment.the clusters surviving in the threshold range of voxel level P< 0.005 clusters≥20 voxels(uncorrected)or voxel level P< 0.001 cluster level P< 0.05(FDR corrected)were reported.Results1.There was no significant difference in age,gender and HAMD score between experimental and control groups before rTMS treatment at baseline.After 20 times of treatment,the HAMD score of the treatment group was lower than before(P < 0.05),and the improvement of emotional function of the treatment group was significantly better than that of the control group(P < 0.05).2.After treatment,the left orbital middle frontal gyrus was more activated than before,and the right hippocampus and parahippocampal gyrus were lower than before;Between the left anterior cingulate gyrus and the left posterior superior frontal gyrus FC increased;The left amygdala betweenthe right middle temporal gyrus,the left middle occipital gyrus and the right upper margin FC increased;Between the left amygdala and the left parahippocampal gyrus FC less than before.The treatment group compared with the control group,FC between left anterior cingulate gyrus and right orbital inferior frontal gyrus,left caudate nucleus,right parahippocampal gyrus increased;FC between left anterior cingulate gyrus and Left amygdala decreased.3.After treatment,the activity intensity or synergy of internal neurons in the DMN decreased,and the specific brain regions were the right parahippocampal gyrus,hippocampus,middle temporal gyrus,angular gyrus and supraorbital frontal gyrus;The activity intensity or synergy of neurons in the internal local brain region of the ECN increased,the specific brain region is the left orbital middle frontal gyrus,the inferior parietal angular gyrus;The SN internal local brain region neuronal activity synergy increased,the specific brain region is the right supplementary motor region;The FC of the internal brain region of the SN increased between the left caudate nucleus and the anterior cingulate gyrus;The FC between SN and ECN was increased,which showed between the left anterior cingulate gyrus and the dorsolateral superior frontal gyrus,inferior parietal angular gyrus and inferior orbital frontal gyrus;The FC between SN and DMN increased,showing between the left anterior cingulate gyrus and the right superior marginal gyrus and parahippocampal gyrus;The FC between DMN and ECN increased,showing the left DLPFC and left temporal pole,anterior cuneus and right inferior temporal gyrus,middle temporal gyrus and inferior temporal gyrus.ConclusionHigh-frequency rTMS can effectively relieve the depression of PSD patients.The three-network model and the partial change of prefrontal-limbic system loop function may be the core of the neural mechanism of rTMS in the treatment of PSD.