Study Of Multimodal Neuroimaging With Late-life Depression

Depression is a kind of mental disorder involving multiple brain regions and systems.It is characterized by persistent and significant depression,insomnia and dreaminess,and difficulty in concentration.Severe patients are unable to lead the normal life,work,participate in social activities,and even pessimistic,accompanied by suicidal intention or behavior.Late-life depression(LLD)patients are often accompanied by a variety of other physical diseases,and their conditions are more complex than those of young people.Moreover,the treatment remission rate of late-life depression patients is relatively low.Their cognitive functions are often impaired after treatment,which has a great impact on the daily life of the elderly.At present,there have been a number ofMRI studies in older patients with depression,and some progress has been made;However,due to the complexity of the pathogenesis of depression,there are individual differences in age,gender,years of falling ill and other physiological aspects of the subjects,and there are some limitations in the study of single mode magnetic resonance,and researchers still have not reached a consensus on the pathogenesis of late-life depression.In order to overcome the limitations of research data from a single modal,in this study,multi-modal data such as resting state functional magnetic resonance imaging(rs-fMRI),structural magnetic resonance imaging(sMRI)and clinical neurological scale data will be systematically collected,to seek neuroimaging markers of late-life depression.First of all,in this paper,voxel-based morphometry(VBM)was used to compare the structural magnetic resonance imaging data between the late-life depression group and the health control group.Secondly,two-sample t-test was used to compare the amplitude of low frequency fluctuations(ALFF)and regional homog eneity(Re Ho)of the resting state functional magnetic resonance imaging between the late-life depression group and the health control group.Afterwards,the different brain regions obtained above were used as the seed point ROI,and the Voxel-wise functional connectivity method was used to study the areas with abnormal functional connectivity in late-life depression.Finally,the Pearson correlation coefficient analysis method was used to explore the correlation between clinical neurological scale and each parameter.Through systematic analysis of multi-modal data such as fMRI,sMRI,brain functional connectivity and clinical scale in late-life depression patients,it was found that there were general abnormalities in function,structure,and brain network connectivity.According to the existing results,structural changes in LLD are not correlated with functional changes.However,both brain regions with significant differences in gray matter volume and brain regions with significant differences in local signal fluctuation characteristics of brain showed extensive abnormalities in functional connectivity.These abnormalities include the abnormalities of DMN default network,the abnormalities of cognitive circuits,which are often involved in depression studies.Combining multiple modes to explore the structural and functional characteristics change of late-life depression can obtain a more comprehensive understanding of the pathogenesis of latelife depression.