Objective To investigate the characteristics and relative pathogenesis of cognitive impairment in people with depression.Methods 24 people with depression and 24 healthy controls were evaluated respectively with HAMD scale,the WCST test,N-BACK task P300 and fMRI.Results (1) The WCST scores,N-back reaction (MRT),the P300 incubation period in depression group were significantly different from those in control group(P300 wave amplitude(4.12± 1.51) μV vs (6.42± 1.73) μV ; P300 latency(392.02±23.60) ms vs (309.43± 21.39) ms,t=4.922,P＜0.01 ; t=12.726,P＜0.01).(2) The illness course had positive correlation with Rep(r=0.596,P＜0.01) and mRT(r=0.518,P＜0.01).The P300 latency had positive correcation with Rpe(r=0.929,P＜ 0.01) and mRT(r=0.939,P＜0.01).(3)Compared with control group,the decreased activation area in patients with depression were as follows:bilateral frontal gyrus,left middle frontal gyrus,inferior frontal gyrus and superior parietal lobule.Conclusion The depressive patients exist cognitive impairment mainly in frontal lobe.The longer with the illness,the wose with the impairment.P300 incubation period is a sensitive indicator of the frontal executive function.

Objective To construct five shRNA-expression plasmids and to investigate the expression of Smad2 in TGF-?/ Smads signal transduction treated with shRNA-expression plasmid.Methods Five shRNA-Smad2 DNA sequences from mRNA sequence of mouse Smad2 gene were designed and synthesized.DNA oligonucleotides encoding an appropriate shRNA were inserted to shRNA expression vector respectively.Five shRNA-Smad2 expression plasmids were obtained and then transfected into NIH/3T3 cells.The suppressed expression of Smad2 was assessed by RT-PCR and Western-blotting.Results The shRNA-expression plasmid numbered 2.4 could markedly reduce the expression of Smad2.The suppression effect of the RNAi-pool composed of four different plasmids was more obvious than that of any single.Conclusion The shRNA-expression plasmids were successfully constructed,which could specifically and effectively suppress the expression of Smad2.The method of using a mixture of RNAi plasmids to improve the RNAi efficiency was established.

Objective To investigate the characteristics of the depression during emotional processing.Methods 24 participants with first episode of depression and healthy controls were assessed with HAMD scale,using DTI to dectect values of white matter FA,and using fMRI with pictures of emotional stimuli;thus results related with imagings were produced.The results were statistically analyzed.Results The brain areas indicating FA values deference with statistial significance in depression patients compared with the control ones included:left and right frontal lobe (left frontal lobe depression group 0.324 ± 0.090,control group 0.467 ± 0.072,P ＜ 0.01),corpus callosum knee (depression group 0.614 ±0.146,control group 0.734 ±0.063,P＜0.01),anterior cingulate gyrus (depression group 0.222 ±0.035,control group 0.343 ±0.021,P＜0.01) ;the fronal FA values in depression grop were negatively correlated with the duration of bilateral frontal white matter (r =-0.555,P ＜ 0.01).The activation of emotional brain regions stimulated by pictures includes frontal cortex-subcortical reticular system,and the hypothalamus and limbic system.There was a significant difference between two groups.Conclusion There may be abnormal emotional processing dystunction in patients with depression.It may be the pathological basis to have frontal white matter fiber tracts broken.

Objective To investigate the characteristics of functional anatomy of the brain in depression patients with cognitive dysfunction and its pathological basis.Methods Twenty-four patients with first episode of depression,admitted to our hospital from May 2008 to December 2009,and 24 healthy controls,collected at the same time period,were chosen in our study; they were all assessed by Hamilton depression (HAMD) scale and Wisconsin test; fractional anisotropy (FA) values of the various parts of white matter were measured by diffusion tensor imaging (DTI),and functional MRI was performed when the testers were conducting N-back task; the related indicators and imaging results were statistically analyzed.Results The brain areas in the depression group having significant difference as compared with those in the healthy controls (P＜0.05) included the bilateral frontal lobes (the leg bilateral frontal lobe,t=-5.884; the right bilateral frontal lobe,t=-4.517),anterior cingulate cortex (t=-14.402) and corpus callosum (t=-3.701).In patients of depression group,the left frontal FA values were negatively correlated with the disease duration (r=-0.555),and FA values of left bilateral frontal lobe and anterior cingulate cortex were negatively correlated to perseverative responses errors (Rpe) and mean response times (mRT,P＜0.05); the disease duration was positively correlated to Rpe and mRT (P＜0.05).The activating reduced brain areas of the depression group when they were conducting N-back task included bilateral frontal gyrus,left middle frontal gyrus,inferior fiontal gyrus and superior parietal lobule.Conclusion The depression patients have significant cognitive impairment; the damage of frontal white matter fiber and abnormalities of gray matter may be the pathological basis.