Childhood trauma affects autobiographical memory deficits through basal cortisol and prefrontal-extrastriate functional connectivity

Background: Psychological trauma can damage the brain, especially in areas where glucocorticoid receptors are expressed, via perturbed secretion of cortisol. Childhood trauma is associated with blunted basal cortisol secretion, brain alterations, and autobiographical memory deficits referred to as overgeneral autobiographical memory (OGM). However, it remains unknown whether childhood trauma affects OGM through altered cortisol and brain alterations. Methods: Using resting-state fMRI in 100 healthy humans, we examined whether childhood trauma affects OGM through its related basal cortisol and brain functional connectivity (FC). Trauma and OGM were assessed using the Childhood Trauma Questionnaire (CTQ) and Autobiographical Memory Test (AMT), respectively. Basal cortisol levels were measured by 10 points-in-time across two days. Multiple mediation analysis was employed. Results: CTQ was associated with greater semantic-associate memory of OGM, a retrieval tendency toward semantic content with no specific contextual details of an experienced event, as well as blunted basal cortisol levels. While CTQ was correlated with decreased FC between the hippocampus and medial prefrontal cortex (PFC), it showed a more predominant correlation with increased FC between the lateral and anteromedial PFC and extrastriate cortex. Importantly, the increased prefrontal-extrastriate FC completely mediated the relationship between CTQ and semantic-associate memory, affected by hyposecretion of cortisol. Conclusion: Childhood trauma may lead to the lack of visuoperceptual contextual details in autobiographical memory by altering basal cortisol secretion and connectivity of the prefrontal-hippocampal-extrastriate regions. The intensified prefrontal-extrastriate connectivity may contribute to OGM formation by strengthening the semantic content in memory retrieval. Understanding the mechanisms underlying the trauma-cortisol-brain-memory link will provide important clinical implications for trauma-related mental disorders.