Segregated Neural Representation Of Somatic And Psychological And Their Relationship

Psychological and somatic as the two forms of human responses to external stimuli, existed complex relationship. Previous theories thought the psychological caused by the change of somatic perception, or the psychological and the somatic perception were independent each other. However, psychological and the somatic perception interact with each other. Whether psychological and somatic share common neural mechanisms, and whether the functional connectivity between the related brain areas affect the relationship between them, there were less related research. So this study is mainly from these two aspects to study the psychological and somatic.At the same time, Depression Disorder Major(MDD) is usually accompanied by abnormal psychological and somatic symptoms. MDD, with significant and persistent low mood as the main clinical features, is a common phenomenon in emotional disorders. Because of the high prevalence, the possibility of recurrence, and high probability of suicide, it has brought serious economic burden on the family and society. Therefore, the prevention and treatment of depression has not been merely the economic significance but also the social value. Therefore, it is urgent to study and explore the pathogenesis of depression.The core symptoms of depression mainly include depression mood and lack of pleasure, but also include a number of somatic symptoms. Previous most studies emphasized the important role of psychological in depression. There was relatively little research on the relationship between somatic symptoms and the occurrence and development of depression. In the current study the main problems included: first, most studies mainly described the phenomenon about the somatic dysfunction in depression, but few researched the neural basis of somatic symptoms in depression; Second, few studies had focused on depression from two dimensions: somatic and psychological and the segregated neural representation of psychological and somatic. For the study of depression, it was very important to understand the effects of somatic and psychological on the onset and recurrence of depression.So this study is mainly to explore the neural mechanisms of psychological and somatic associated with healthy subjects and patients with depression, and to provide a basis for somatic perception and psychological related brain regions.Study one was conducted to examine the patterns of brain activation during emotional and interoception tasks. There were 170 healthy college students from southwest university taken part in the emotional face matching task, and another 50 healthy college students take part in the interoception task. For emotional face matching task, included two kinds of conditions: emotional face matching and shape matching. We focused on the pattern of brain activation when the emotional face matching minus the shape matching. This was described as the pattern of brain activation related to emotion. For the interoception task, subjects were asked to pay attention to the cue word corresponding to the experimental task. Our main concern was the interoception activated brain patterns, so we used the interoception condition minus exteroreception condition. Thus we got the pattern of brain activation related to interoception. Results showed that the processing of emotional faces mainly activated the brain areas including the amygdala and the dorsolateral prefrontal cortex(DLPFC); while the interoception task activated brain areas mainly including the insula and dorsal anterior cingulate cortex(d ACC). This is in agreement with the previous results.In study two, we used the questionnaire and brain imaging technology to determine the somatic and psychological related brain regions in patients with depression. First of all, we were concerned about the differences in the amplitude of low frequency fluctuations(ALFF) between the two groups; secondly, whether the relationship between depression / somatic score and ALFF in certain areas was differences in the two groups of participants. We used the spm8 One-way ANOVA analysis method; finally, we were concerned about whether the relationship between depression / somatic score and ALFF was moderated by the taking drugs in depression patients. Results found that the difference of the ALFF between the depression patients and the control group was mainly in the subgenual anterior cingulate cortex(sg ACC) region, and the ALFF of this region was positively correlated with the severity of depression; The One-way ANOVA analysis found the relationship between somatic score and the ALFF of insula had interactive effect. That is to say, for patients with depression, somatic score had significant positive correlation with the ALFF of insula, while for the control group, the somatic score and the ALFF of insula showed a significant negative correlation. Similarly, we found the depression score had a significant positive correlation with the sg ACC and ventromedial prefrontal cortex(VMPFC) in the depression, but a significant negative correlation in control group. Finally, the relationship between depression / somatic score and ALFF in patients taking drugs was tending to be normal. Taking together, there are segregated neural representation of psychological and somatic.Study three, we mainly used the brain regions obtained by the Study two, to further explore the relationship between the somatic perception and psychological through the functional connectivity. The results showed that the relationship between somatic perception and psychological was moderated by the functional connectivity between the insula and vm PFC. There was a significant inter-action between somatic perception and psychological, such that higher somatic perception were associated with high psychological for participants with relatively increased functional connectivity between the insula and vm PFC but not for those with decreased functional connectivity between the insula and vm PFC.In summary, this study found the segregated neural representation of psychological and somatic. The somatic related brain areas were mainly concentrated in the insula and the d ACC, and the brain regions processing the depressive emotion were the prefrontal cortex, sg ACC and amygdala. Finally, the relationship between somatic perception and psychological was moderated by the functional connectivity between the insula and vm PFC.