Depression tensor imaging study of depression patients mood processing disorders / 中华行为医学与脑科学杂志

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.

The characteristics of cognitive impairment in depression: a combined functional magnetic resonance and event-related potential study / 中华行为医学与脑科学杂志

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.

Brain electrical source analysis of the response to visual target and distractor stimuli / 生物医学工程学杂志

In this paper, time courses of discrete cortical current sources evoked by target and distractor stimulus are presented in a visual three-stimulus oddball paradigm. 64-channel electroencephalogram (EEG) signals were recorded in healthy subjects in the paradigm where the P3b component of the P300 is evoked in the detection of rare events (target and distractor) and the P3a component is mainly produced by distractor events. A regional source model with constraints of spatial coordinates from fMRI was then applied to event-related potentials (ERPs) data in the target and distractor conditions. Activities of regional sources indicated bilateral inferior parietal lobe, posterior parietal cortex and inferior temporal cortex mainly contribute to the P3b, while the P3a was mainly produced by bilateral insula, bilateral precentral sulcus and cingulate gyrus. Target processing involved parietal lobe, inferior temporal cortex and left insula engaged in stimulus-driven attention process, goal-directed attention process, categorization of visual stimuli and memory retrieval, while distractor processing involved right insula and cingulate gyrus engaged in attention switching and reengagement of attention resource.

Study on the influence of simulative EEG modulation magnetic field on the discharge of median raphe nuclei / 生物医学工程学杂志

In this paper the response characteristic of the nerve fiber to the modulation magnetic field induction is studied by using the method of numeric simulation. It is found that the nerve fiber is sensitive to the low frequency modulated signal but not to the high frequency carrier wave. A simulative EEG signal generator is developed according to the change of EEG rhythm during the sleep. The simulative EEG square wave is modulated by high-frequency magnetic impulse. The modulation magnetic field is coupled into the rabbit's brain to study the influence of magnetic stimulation on the discharge of 5-hydroxytryptamine (5-HT) nerve cell. The experiment results demonstrate that discharge frequency of median raphe nuclei related to sleep changes significantly and the discharge becomes slow, which shows that magnetic stimulation can inhibit electrical activity of 5-HT nerve cell and provide a new way to improve insomnia.

Study on the function localization during different brain calculation tasks / 生物医学工程学杂志

The aim of this study is to define the anatomical localization of corresponding brain function area during calculating. The activating modes in brain during continuous silent calculating subtraction and repeated silent reading multiplication table were compared and investigated. Fourteen volunteers of right-handedness were enrolled in this experiment. The quite different reaction models in brain area during the two models of calculation revealed that there are different processing pathways in brain during these two operating tasks. During continuous silent calculating, the function areas were found localized on the posterior portion of superior and middle gyrus of frontal lobe and the lobule of posterior parietal lobe (P < 0.01, T = 5.41), demonstrating that these function areas play an important role in the performance of calculation and working memory. During repeated silent reading multiplication table, the activating cluster was found only located in in the gyri occipital lateral(P < 0.01, T = 4.77).

Effect of different attention states on auditory ERP and EEG power / 中华物理医学与康复杂志

Objective To study the effect of different attention states on auditory ERP and EEG power in normal subjects. Methods In three different states such as passive attention,active attention with target counting and active attention without target counting,EEG were recorded using oddball paradigm in 8 normal subjects while the test tones were presented;Then the peak-peak amplitude and latency of ERP were evaluated and the EEG power spectra were observed. Results The condition of active attention with target counting resulted in the smallest peak-peak amplitude of P 2-N 1 and the largest one of P 3-N 2,and it led to the increment of EEG power at the frequency of 10Hz,while the latencies did not differ among the three different attention states. Conclusion Reduced P 2-N 1 amplitude and increased P 3-N 2 amplitude reflected the allocation changes of attention resource in different states,and increased EEG power reflected more energy consumption in the process of recognition and memory,but the latency was relatively stable and not affected significantly by subject's attention condition.