Brain Structural Base Of Dispositional Optimism And Its Mechanism With Anxiety

Dispositional optimism is an important product of human evolution. This individual difference variable plays a core role in human experience. Dispositional optimism is related to positive expectations regarding possible outcomes such that optimistic individuals are confident that they will attain their goals successfully. Many previous studies have shown that dispositional optimism is beneficial to physical and psychological wellbeing. The use of magnetic resonance imaging allows us to examine these differences with voxel-based morphometry(VBM) analysis, which provides a structural measure of gray matter. In this study we use VBM to investigate the brain structure of dispositional optimism. Anxiety is an ubiquitous emotional experience, it means people will occur uneasy and negative emotion when he face unknown situation. Anxiety related to negative expectations regarding possible outcomes such that anxiety individuals are confident that they will not attain their goals successfully. Many previous studies have shown that anxiety is bad to physical and psychological wellbeing. Optimistic individuals will hold a positive mental attitude to cope with difficulties, thus, they experienced little anxiety. Pessimistic individuals will hold a negative mental attitude to cope with difficulties, thus, they experienced more anxiety. There has negative relation between the score of dispositional optimism and anxiety. There are many studies focus on the relationship between dispositional optimism and anxiety. These studies focus on that dispositional optimism affect anxiety through what kind of behavior(for example, defense mechanism or coping style). In this study we aimed in to find whether dispositional optimism affect anxiety through the volume of some brain region.In the first study, there are374healthy college students from southwest university take part in our study. Every participants complete the revised Life Orientation Test(LOT-R) before FMRI scanning. We use the LOT-R to measure the level of dispositional optimism of every participants. We told the participants closed their eyes when scanning. At last only the data for359participants were analyzed for the data of15participants was excluded for some reasons(abnormal anatomy, big head moving or invalid questionnaire). The results showed that individual dispositional optimism was associated with larger gray matter volume of a cluster of areas that included the left thalamus that extended to the left parahippocampal gyrus. Thalamus might play an important role in emotion regulation, higher dispositional optimism individuals might have better emotion regulation abilities. Parahippocampal gyrus might play an important role in emotion regulation, higher dispositional optimism individuals might experience more positive emotions and feelings.All the359participants of first study take part in the second study, every participants complete the Rating Anxiety Scale. The Rating Anxiety Scale is a questionnaire that evaluate individuals anxiety level in the latest week. In this study we use mediation analysis method to investigate the relationship between dispositional optimism and anxiety. we use the volume of brain region results from the first study as mediation variable, the score of LOT-R as independent variable and the score of S AS as the dependent variable. The result showed that the volume of the brain region results from the first study was partly mediation the relationship between dispositional optimism and anxiety. It means that dispositional optimism influence the level of anxiety partly by the volume of left thalamus that extended to the left parahippocampal gyrus. May be the dispositional optimism influence the level of anxiety through the function of thalamus and parahippocampal gyrus.The study use VBM to investigate the brain structure of the dispositional optimism, and the results showed that individual dispositional optimism was associated with larger gray matter volume of a cluster of areas that included the left thalamus that extended to the left parahippocampal gyrus. It means the individual who have higher level of dispositional optimism have bigger gray matter volume of this brain region. The individual who have higher level of dispositional optimism might have better emotion regulation ability and experience more positive emotions and feelings. This study exceed the limitation of small sample and apply the relation analysis to investigate the brain structure of individual difference of the dispositional optimism. It provide the proof of the biophysical dimension for the study of dispositional optimism. This study apply the mediation analysis method to investigate the neuronal mechanism of dispositional optimism and its related brain structure with anxiety, and the results showed that dispositional optimism influence the level of anxiety partly by the volume of left thalamus that extended to the left parahippocampal gyrus. Dispositional optimism influence the level of anxiety might through the emotion regulation ability of thalamus and the emotion memory and emotion experience function of parahippocampal gyrus. This study not only provide the proof of neuronal mechanism for the study of relationship of dispositional optimism and anxiety, but also, provide new idea for the study of the relationship between personal characteristics and emotion and felling.