| Part 1A resting-state f MRI study of treatment-na?vedepressionObjects: The precisediagnosis for depression still lacks of biomarkers.Resting-statefunctional magnetic resonance imaging(f MRI)is a possible tool to explore the neurobiological mechanisms of depression.The current study aimed to reveal the pathological mechanism of depression,based on level of the whole brain and the level of three core brain networks(default mode network(DMN),central executive network(CEN),salience network(SN)),respectively.Methods: Twenty-seven treatment-na?ve depression patients and 27 age,gender,educational years matched normal controls were enrolled.All of them were scanned with resting-state f MRI.The amplitude of low frequency fluctuation(ALFF)and functional connectivity degree(FCD)differences between the two groups were respectively comparedat the whole brain level and DMN,CEN,SN levels.Results: Compared to normal controls,depressive patients showed increased ALFF in right orbital frontal cortex(OFC)and decreased ALFF in left striatal cortex(caudate nucleus and putamen)and medial prefrontal cortex;while there were no significant differences of ALFF in the above three brain networks betweenthese two groups.In addition,depression patients presented increased FCD in right dorsal anterior cingulated cortex(ACC)and decreased FCD in right inferior parietal lobe,as well as the FCD in CEN compared with normal controls.Conclusions: The major abnormal regional spontaneous brain activity of depression was located in right OFC,left striatal cortex and medial prefrontal cortex.The abnormal connectivity degree seemed to happen in disrupt regions,including right dorsal ACC,right inferior parietal lobeand CEN,which suggested the activity of local brain regions and brain networks should be combined to assess the neurological pathological mechanisms of depression.Part 2Therapeutic mechanism of r TMS in depression: a resting-state brainimagingstudyObjects: The antidepressant effect of repetitive transcranial magnetic stimulation(r TMS)is moderate andinter-individual variation is quite large,the therapeutic mechanism of r TMS is depressing unclear.To explore therapeutic mechanism of r TMSin depression using rsf MRI would be helpful for further understanding of thepathological mechanism of depression and optimizing the effects of r TMS.Methods: Fifteen treatment-na?ve depression patients were treated by 10 HZ r TMS on left dorsal lateral prefrontal cortex(DLPFC)for 10 sessions and scanned with resting-state f MRI before and after r TMS.The ALFF and FCD differences between pre-TMS and post-TMS groups were respectively comparedbased on the whole brain level and DMN,CEN,SN levels.Results: After r TMS treatment,depression patients presented increased ALFF in left DLPFC,superior frontal gyrus,while no significant differences of ALFF in the three brain networks were found between pre-TMS group and post-TMS group.In addition,depression patients showed increased FCD in right dorsal ACC andsuperior temporal gyrus,as well as decreased FCD in bilaterallingual gyrus after r TMS;while FCD in CEN was significantly increased after r TMS.Conclusions: The decreased FCD in CEN at baseline was significantly improved after r TMS,while the increased FCD in right dorsal ACC at baseline was further increased by r TMS.ALFF in left DLPFC(stimulated target)was increased after r TMS,which improved the abnormal function of CEN.Part 3Prediction mechanism of r TMS in depression: a resting-state brainimaging studyObjects: The treatment efficiency of r TMS for depression is still unsatisfactory,and thefactors influencing the effects remain unclear.Resting-state f MRI could be a usefultool to predict theclinical effects of r TMS on depression,which would help choosing the most adaptive population of r TMS.Methods: Twenty-seven treatment-na?ve depression patients were treated by 10 HZ r TMS on left DLPFC for 10 sessions and scanned with resting-state f MRI at baseline.The severity of depressive and anxious symptoms were assessed with Hamilton Depression Scale(HAMD)and Hamilton anxiety Scale(HAMA),respectivelybefore and after r TMS treatment.Correlation analysis was used to compute the relation between anti-depression and anti-anxiety effects of r TMS with pre-treatment ALFF and FCD.Results: Anti-depression effect of r TMS was significantly negatively correlated with pretreatment ALFF in left precentral gyrus andlingual gyrus,while it was positively correlated with ALFF in left ventrolateral prefrontal cortex and posterior cingulated/precuneus.Anti-anxiety effect of r TMS was negatively correlated with ALFF in left precentral gyrus andpositively correlated with ALFF in right medial prefrontal cortex and posterior cingulated/precuneus.Anti-depression effect of r TMS was positively correlated with FCD in right fusiform gyrus.Anti-anxiety effect of r TMS was negatively correlated with FCD in dorsal medial prefrontal cortex and positively correlated with FCD in left inferior occipital gyrus.The strength of negative functional connectivity between stimulated left dorsal lateral prefrontal cortex(DLPFC)and nucleus accumbens(NAcc)was higher in early improvers than that in non-improvers.Conclusions: Increased baseline local cerebral function in prefrontal and postcingulated cortex could positively predict anti-depression and anti-anxiety effects of r TMS;while increased local cerebral function in precentral gyrus could have negative prediction effects on anti-depression and anti-anxiety effects of r TMS.Increased baselinefunctional connectivity degree in right fusiform gyrus andinferior occipital gyrus could positively predict anti-depression and anti-anxiety effects of r TMS;while increased functional connectivity degree in dorsal medial prefrontal cortex could have negative prediction for anti-anxiety effect of r TMS.Higher negative connectivity between stimulated left dorsal lateral prefrontal cortex(DLPFC)and nucleus accumbens(NAcc)could positively predict anti-depression and anti-anxiety effects of r TMS. |
PDF Full Text Request