Neural Basis Of Trait Anxiety And Neural Mechanism Of Trait Anxiety Individuals Under Uncertainty

Diagnostic and Statistical Manual of Mental Disorders noted that anxiety disorders showed excessive anxiety and tension properties, and with some of the behavioral and mood bias, excessive fear and anxiety in real life. Although studies have shown that cognitive behavioral therapy and mindfulness therapy have demonstrated a certain effect in relation to the of anxiety disorders, but so far have no effective way to prevent and treatment anxiety disorders(particularly generalized anxiety disorder found). Trait Anxiety refers to a personality trait in the individuals with a general and stable afraid, or a kind of tendency and susceptibility to anxiety. High trait anxiety persons may have some anxiety-liking behavioral and mood bias, such as excessive anxiety for the uncertain events and concerns, high trait anxiety individuals deemed susceptible to be pre-clinical anxiety disorders. Because comorbid anxiety disorders are too more, it is difficult to conduct a strictly controlled experimental study, according to the perspective of continuity of the development of anxiety, conduction of systematic studies of key cognitive component of anxiety not only provide better knowledge and understanding of anxiety, but also provide experimental evidence for non-invasive brain stimulation to the therapy of anxiety.According to the Diagnostic and Statistical Manual of Mental Disorders, anxiety individuals often shows a fear issue too much about the future uncertain events. These cognitive bias of processing the uncertainty affects the individuals’ emotional experience and behavior, so, conducting studies under uncertain circumstances to explore the cognitive and emotional information processing in trait anxiety can helps us to understand the anxiety. Based on previous studies, we attempt to structure a combination of structure magnetic resonance imaging and Resting-state functional magnetic resonance imaging techniques fear morphological characteristics of individual brain structures and spontaneous brain activity patterns in trait anxiety, then, with the task-based functional magnetic resonance imaging, we aimed to explore the behavioral and neural basis of the cognitive and emotional processing under uncertainty.In the first study, we decided to explore the correlations of brain structure and brain activity with trait anxiety in normal individuals. Specifically, we investigated the correlations between trait anxiety and regional grey matter volume(r GMV) and regional BOLD, using the Amplitude of Low Frequency Fluctuations(ALFF) as an index in 382 university students. The results showed that the level of trait anxiety was negatively correlated with r GMV in the right middle occipital gyrus. This result indicates that individuals with high trait anxiety tend to have less image processing during consciousness. Furthermore, we found that trait anxiety was positively correlated with the ALFF in the bilateral superior frontal gyrus and the right supplementary motor area, and negatively correlated with the ALFF in the cerebellum and the thalamus. These results indicate that individuals with high trait anxiety may be more sensitive to relationships and sensory information. Overall, this study’s findings suggest that individuals with high trait anxiety have attenuated image processing on the conscious level, and exhibit stronger induced sensibility and over-processing of relationships, which is a brain imaging precondition for psychiatric disorders.In the second study, we first decided to explore the brain correlates of processing uncertain information in individuals with high trait anxiety using the learn-test paradigm. Behaviorally, the percentages on memory test and the likelihood ratios of identifying novel stimuli under uncertainty were similar to the certain fear condition, but different from the certain neutral condition. The brain results showed that the visual cortex, bilateral fusiform gyrus, and right parahippocampal gyrus were active during the processing of uncertain cues. Moreover, we found that trait anxiety was positively correlated with the BOLD signal of the right parahippocampal gyrus during the processing of uncertain cues. No significant results were found in the amygdala during uncertain cue processing. These results suggest that memory retrieval is associated with uncertain cue processing, which is underpinned by over-activation of the right parahippocampal gyrus, in individuals with high trait anxiety. Secondly, we aimed at exploring the neural basis of the unknown emotional stimuli processing in trait anxiety individuals by using a learning-testing task paradigm in f MRI. The results showed that the visual cortex, bilateral hippocampus gyrus, bilateral middle temporal gurus, bilateral temporal pole, left anterior cingulum cortex, right insula and right medial frontal gyrus were activation during the unknown neutral versus anticipant neutral stimuli. Meanwhile, there was no significant difference in the contrast of unknown neutral and the unknown fear stimuli. Moreover, we found that trait anxiety level was positively correlated with the BOLD signal level of the right insula and left anterior cingulum cortex during the unknown neutral stimuli processing. These results suggest that the emotion processing rather than cognitive processing is associated with the unknown neutral stimuli processing in anxious individuals, which was underpinned by over-activation of the right insula and left anterior cingulum cortex. Thirdly, we set out a learning-testing task to explore the neural basis of the self-emotion regulation of the anticipant emotion in trait individuals. The results showed that the emotion experience which was underpinned by the right insula decreased with the passage of experiment trials. Moreover, in the second run of this study, the bilateral fusiform gyrus, left postcentral gyrus were activation during the cue encoding, and a significant negative correlation between the left postcentral gyrus and insula was found, which suggested that the somatosensory arousing before the upcoming emotional stimuli play an regulation role in the emotional experience. Furthermore, we also found that there was a significant negative correlation during the cue encoding and a significant positive correlation during the negative stimuli processing between the trait anxiety scores and the BOLD level of left postcentral gyrus in the second run of this experiment. These results suggested that weaken of the emotion regulation strategy of the translation from the emotional to somatosensory arousing in high trait anxiety individuals in the anticipant emotion situation, and proved the somatosensory arousing occurred during the emotional processing in anxious individuals.In study 3, we have examined people with different levels of anxiety in blur relation in the form of graphs and verbal reasoning and cognitive processing in neural mechanisms. There was no significant difference in the behavioral level in the correct percentage and reactive time between the inferences of figure uncertain relations and the figure certain relations. Later we found a significant positive correlation between scores of trait anxiety and the RT of inference of figure uncertain relations. Furthermore, the correct percentage of inference of verbal uncertain relations was higher than of the certain relations. Based on our f MRI results, we found that the left putamen and the left cuneus showed more activation in the figure uncertain relation processing, and there was a significant positive correlation between the trait anxiety scores and the left putamen. Therefore, we believe that the putamen activation level was related to the anxiety level of individuals, and in figure relation processing under uncertainty, high anxiety individuals generate more anxiety feelings, so that the impact on relations reasoning. Moreover, we found that right middle frontal gyrus, right inferior frontal gyrus, left middle frontal gyrus, left precentral gyrus, left middle temporal gyrus and left superior temporal gyrus showed more activation in the verbal relation processing under uncertainty, and a significant positive correlation between the trait anxiety scores and the brain signals of left middle temporal gyrus and left superior temporal gyrus. In sum, we believe that, firstly, the individuals in the processing of uncertainty relations are subthreshold anxious, and this subthreshold anxious activate the verbal stream, the more the trait anxiety scores, the higher the verbal stream activation. Then the matches of the verbal stream and the verbal stimuli could increase the performance of logical thinking under uncertainty. In summary, this paper try to explore the relationships between the trait anxiety and the brain structure, properties of the spontaneous activation levels, uncertain process of cognitive biases and its neural basis by using magnetic resonance imaging. This paper is of immense value, because it can help to establish brain-behavior relationships, clarify the nature of dysfunctional processes in anxiety group.