Alterations in self-related brain networks in autism spectrum disorder: a systematic review of functional and structural magnetic resonance imaging studies.

Autism spectrum disorder (ASD) involves alterations in social communication and restricted, repetitive behaviors. Emerging evidence highlights atypical self-awareness as a key factor in ASD-related social impairments. However, the neural mechanisms underlying differences in self-processing remain fragmented. This systematic review synthesizes findings from 49 functional magnetic resonance imaging (fMRI) and structural magnetic resonance imaging (sMRI) studies (2000-2025) to explore self-related brain networks in ASD, based on the hierarchical self-model comprising interoceptive, exteroceptive, and mental levels. Across all three levels, consistent atypicalities were observed in ASD. The interoceptive level (insula, thalamus) showed altered functional connectivity (FC) and gray matter density, associated with atypical bodily and affective self-awareness. The exteroceptive level, which includes the medial prefrontal cortex (mPFC), temporoparietal junction (TPJ), and premotor cortex (PMC), exhibited reduced long-range FC and local coherence, potentially reflecting atypical self-other differentiation and communication. The mental level, involving the anterior and posterior cingulate cortices (ACC and PCC), revealed decreased FC and interhemispheric coherence, implicating atypical reflective self-processing. Disrupted cross-level interactions further suggest a breakdown in hierarchical self-integration. These findings emphasize the importance of self-related network alterations in ASD and support their inclusion in neurocognitive models of autism.