Short Summary/Abstract:

Childhood trauma is associated with a range of structural brain alterations, including cortical thinning and reduced gray matter volume in frontal regions such as the dorsolateral and ventromedial prefrontal cortices (DLPFC, VMPFC), which are implicated in cognitive control, source monitoring, and the regulation of internally generated stimuli. Additional trauma-related differences have been reported in the anterior cingulate cortex (ACC), associated with error detection and cognitive regulation, and temporal regions such as the superior temporal gyrus, which are involved in auditory processing. Some trauma subtypes, such as childhood sexual abuse, have also been linked to increased gray matter volume in the amygdala, suggesting trauma-specific pathways that may not directly relate to hallucination mechanisms. While structural alterations have been observed in both trauma-exposed and non-exposed individuals who experience hallucinations, it remains unclear whether the neural pathways leading to hallucinations differ based on trauma history. Theoretical models suggest that hallucinations may result from distinct cognitive processes - including source monitoring deficits, intrusive memories that are poorly inhibited, or over-weighted perceptual priors. The second of these pathways, in particular, has been proposed to account for hallucinations following trauma exposure. This study will explore whether such proposed mechanisms map onto distinct structural brain patterns in individuals with and without childhood trauma histories.