IntroductionSelf-disclosure is integral to forming intimate connections within interpersonal exchanges. While its advantages are widely acknowledged, the cerebral basis of self-disclosure is not thoroughly understood. Insight into its neural underpinnings is crucial for refining therapeutic approaches, especially for challenges associated with self-disclosure. MethodsOur study probed the association between spontaneous neural activity, gauged via resting-state fMRI, and self-disclosure tendencies among 258 healthy university students, employing Regional Homogeneity (ReHo) and behavioral correlation analysis. We also explored the mediating effect of self-consciousness on this relationship. ResultsThe ReHo-behavior correlation analysis uncovered that higher ReHo values in the insula are predictive of greater self-disclosure in social settings. Additionally, the mediation analysis identified self-consciousness as a partial intermediary between spontaneous neural activity in the insula and self-disclosure behaviors. ConclusionThe findings imply that decreased similarity in the insula during rest-state may amplify self-conscious emotions such as embarrassment, thus illuminating the cognitive processes that underlie disclosure behaviors. Critically, these insights have practical ramifications for enhancing therapeutic methods and communication skills by aiding individuals in navigating self-consciousness obstacles, thereby promoting more transparent and efficacious self-disclosure.