Research Of Abnormal Emotion In Major Depression Disorder With Brain Structural And Functional MRI

PartⅠResearch of white matter with diffusion tensor imaging in major depressive disorder Objective:To observe the integration of white matter in the whole brain of the cases with major depressive disorder(MDD) by the diffusion tensor imaging.Methods:There were 10 cases of first-episode MDD collected from Dec/2006 to Nov/2007,and 10 normal volunteers matched with gender and age as control.It was acquired in 10 patients with DTI scan before and after antidepressant therapy and 10 normal volunteers.Those images of DTI scan of MDD cases before therapy,MDD cases following therapy,and normal volunteers were compared by VBA.Results:(1) The reduced FA values of the white matter were found in the right superior frontal gyrus,the fight middle frontal gyrus,the right anterior cingulum,and the left middle frontal gyrus in the MDD cases before therapy compared with the control.(2) No significant correlation was found between the brain areas with reduced FA values and the symptom severity or the history of the first-episode MDD cases.(3) The FA values of the white matter in the whole brain of the MDD cases before therapy were never higher than those of the controls.(4) There was no significant difference of the FA valuses of the whole brain in the MDD cases before therapy and those of the cases afer therapy(p＜0.001,voxel＞30).Conclusions:(1) There were abnormal white matter integration in prefrontal area and anterior cingulum in the MDD cases.(2) The damaged structural connectivity of the neural circuit underlines the MDD mechanism.PartⅡVoxel-based morphometrical study of grey matter changes in first-episode patients with major depressive disorderObjective:To observe the grey matter changes in first-episode patients of major depressive disorder compared with the normal control by VBM.Methods:First-episode MDD(n=10) cases and 10 normal volunteers matched with age and gender were collected from Dec/2006 to Nov/2007.The patients were taken MRI scan before therapy and 8w following therapy. The same MRI scan was introduced to the normal controls also.The images were normalized and compared about grey matter density with VBM.Results:(1) MDD subjects showed decreased grey matter density in left medial and middle frontal gyrus compared to the healthy. (2) No significant correlation was found between the brain areas with reduced density and the symptom severity of the MDD.(3) The grey matter densities of the whole brain in the MDD patients after therapy were not different from those of MDD patients before therapy(p＜0.01). Conclusions:(1) There was reduced grey matter density in the area of prefrontal lobe of the MDD patients.(2) Morphologic abnormalities in DLPFC are correlated with the emotional dysfunction in MDD patients.PartⅢAbnormal brain emotional processing in major depressive disorderObjective:To investigate the abnormal functional activity in the implicit and explicit processing by fMRI.Method:The 10 cases of first-episode patients and another 10 normal controls were collected from Dec/2006 to Nov/2007 and were taken MRI scan.The fMRI tasks were implicit and explicit affection recognition with standard facial stimuli of happiness and sadness.The activation areas in brain involved in processing facial affection were analyzed with Statistical Parametric Mapping 2(SPM2).Results:(1) In the healthy subjects to expicit emotional task,the happy faces can induced activation of anterior cingulated cortex(BA24),temporal lobe(BA22),parietal lobe(BA7);and the sad faces can induce activation of occipital lobe(BA17,19),parie(BA3,7) and anterior cingulated cortex(BA32). There were enhanced responses to happy faces.Healthy subjects exhibited activation of frontal(BA10) and occipital lobe(BA19) with implicit task by happy faces,and exhibited activation of bilateral parietal lobe(BA7),anterior cingulated cortex(BA32) by sad faces. Higher responses were found to happy faces than to sad faces.(2) In the explicit task of sad facial expression for MDD patients,activation of bilateral occipital lobe(BA17) were enhanced,and response of temporal(BA21,38),frontal(BA6,9) and anterior cingulated cortex(BA32) were also observed,while activation of thalamus,posterior parietal lobule(BA40) and occipital lobe(BA18,19) by happy faces were observed.In the implicit task for MDD patients,there were increased activation in postcentral gyrus of parietal lobe (BA2),precuneus(BA7),bilateral occipital lobe(BA19) by sad expressions,with decreased activation signal in left hippocampus,right parietal labe(BA31) and middle frontal gyrus(BA10)by happy expressions.(3)Contrast to the healthy group,increased activation in thalamus,superior frontal gyrus(BA13),caudate and bilateral insular(BA13)were significant(p ＜0.01) in MDD group by sad faces in the explicit task.However,no activation increased in the healthy group with contrast to the MDD group.In the implicit task,increased activation in parietal lobe(BA40),gyrus(BA47),insular(BA13) were significant(p＜0.01) in the MDD group compared with the healthy group.Conclusions:(1) The pocessing of explicit emotional perception was different from that of the implicit emotional perception in healthy subjucets.(2) The processings of explicit and implicit emotional perception are different in MDD subjects,which are distinct from those of the healthy subjects.There were higher signals induced by sad faces in MDD subjects.(3) Regardless of the tasks,with sad faces, MDD subjects showed higher activation than did controls,and lower activation with happy faces.It indicated that there was neural impairment in the MDD,with decreased response to positive emotion and increased response to negative emotion.(4) Impairments in the neural processing of affective facial expressions in MDD were evident in thalamus and insular. Maybe abnormal brain function in the subcortex areas underlines the emotional disorder in MDD.PartⅣDifferent deactivation in patients with major depressive disorder during facial expression recongnition:an fMRI studyObjective:To investigate whether deactivation in major depressive disorder is different from healthy controls by means of fMRI.Methods:10 depression patients and 10 healthy controls underwent fMRI while recognizing the affecional facial expressions alternating with rest. Patients group underwent fMRI scans at baseline(week 0) and at 8w following treatment. Following the baseline scan,the patients received antidepressant with one kind of SSRIs daily. Images were analyzed with SPM2 and principal component analysis.With minusing the task-state activation from the rest,we compare the different deactivation in implicit and explicit recognition tasks.Regions of deactivation were observed in patients and controls.Results:(1)Deactivation of healthy controls were parietal(BA31,39),temporal(BA22), frontal lobe(BA8,9,10),putamen and cerebellum.While deactivation of the first-episode MDD patients were precuneus(BA7),anterior cingulated gyrus(BA32),bilateral temporal lobe(BA22),putamen,insular(BA13),parahippocampus gyrus.(2) In explicit task,regions of deactivation were increased in parahippocampus(BA30,35),insular(BA 13) and occipital lobe(BA17,28) in medicine-free patients.Deactivation of bilateral thalamus,right putamen,frontal(BA6) and parietal lobe(BA3) were increased in the MDD patients than the contrals,while deactivation of hippocampus and temporal lobe(BA22) were decreased after therapy(p＜0.01) in the implicit task.(3) Deactivation of the MDD patients for implicity tasks was significant before and after therapy,especially in the thalamus,caudate,insular (BA13) and temporal lobe(BA22).No regions of increased deactivation were observed after therapy(p＜0.01) and controls(p＜0.01) comparing to the medicine-free MDD patients.Conclusions:(1) The brain default mode network can be evaluated undirectly from deactivation areas,including anterior cingulated cortex,medial prefrontal gyrus,precuneus and bilateral superior temporal gyrus.(2) The observed increased deactivation in limbic system is essential for the abnormal intrinsic brain function in depression patients.(3) Disorder function of subcortex-limbic areas underlines the psychopathology of depression.(4) Deactivation of subgenual cingulate increases in the patients medicine-free while compared with the contrals and post-therapy.Antideprssants may improve abnormal intenal activity of MDD.