Neural Correlates Of Optimistic And Depressive Selfevaluation Tendencies In Relation To The Resting-state Default Mode Network

Self-evaluation tends to be overly optimistic, it is motivated to exhibit a positivity bias of evaluating people themselves. Reduced optimism has been linked to increased depressive symptoms. The positivity bias of self-evaluation tends to protect our selfesteem and relieve the anxiety which is generated from cognitive heuristics when selfesteem is not at stake. Recent neuroscience research supports the idea that inducing the need for self-esteem protection changes the neural profile underlying exaggerated positivity. When self-esteem is threatened, exaggerated positivity in self-evaluation engages orbitofrontal cortex and decreased middle frontal gyrus activation. In contrast, exaggerated positivity arising in the absence of self-esteem threat tends to reduce orbitofrontal cortex activation. Medial prefrontal cortex is responsible for differentiating self and others; whereas the ventral anterior cingulate cortex is referred to distinguishing the negative and positive information. The processing of ventral anterior cingulate cortex and medial orbitofrontal cortex is driven by the social evaluation. All those brain areas belong to the default mode network in which it is endowed the function of representing the psychological characteristics of self and others, and the function of social cognition. The default mode network is comprised of three components, the medial prefrontal cortex plays a key role in self-referential and social cognition, the subsystems are also important for social understanding. Previous research has demonstrated that optimism is negatively associated with depression. Increased optimism has been linked with the decreased depressive symptoms.Given the importance of optimism for adaptive functioning, surprisingly little is known about resting brain states underlying optimistic and depressive tendencies. In the current study, two resting-state indices were used to examine neural correlates of the default mode network(DMN) associated with optimistic and depressive self-evaluation tendencies. In the current study, we adopted a behavioral task, four questionnaires, and two resting-state indices to explore the psychological and neural mechanism of optimistic self-evaluation. The personality traits rating task and four questionnaires was used to investigate the psychological mechanism of ubiquitous optimism in study one. Participants first were asked to complete four measures and then to rate some positive or negative personality traits of themselves when compared with the average students. Study two investigated the neural correlates of self-evaluation and DMN. Due to the selfreferential nature of the DMN, the analysis was constrained within it. Across different indices, bilateral superior frontal gyri of the dorsolateral prefrontal cortex(DLPFC) and bilateral superior medial frontal gyri of the dorsal medial prefrontal cortex(DMPFC) played a key role in maintaining spontaneous optimistic self-evaluative tendencies. Conversely, decreased activity in the dorsolateral prefrontal cortex and bilateral medial orbitofrontal cortices(OFC) were related to accentuated depressive symptoms. Together, results highlight the pivotal roles of the dorsolateral prefrontal cortex and dorsal medial prefrontal cortex in mediating valences of self-referential content. Comparing to the previous task-related fMRI research, the current study was the first investigation to explore how the resting-state default mode network represents the optimistic and depressive tendencies of self-evaluation.