Structural and Functional Connectivity Underlying Gray Matter Covariance: Impact of Developmental Insult.

Structural covariance networks (SCNs) may offer unique insights into the developmental impact of childhood maltreatment (CM) because they are thought to reflect coordinated maturation of distinct gray matter regions. T1-weighted magnetic resonance images were acquired from 121 young people with emerging mental illness. Diffusion-weighted and resting-state functional imaging was also acquired from a random subset of participants (n = 62). Ten study-specific SCNs were identified using a whole-brain gray matter independent component analysis. The effects of CM and age on average gray matter density and the expression of each SCN were calculated. CM was linked to age-related decreases in gray matter density across an SCN that overlapped with the default mode network (DMN) and frontoparietal network. Resting-state functional connectivity (rsFC) and structural connectivity were calculated in the study-specific SCN and across the whole brain. Gray matter covariance was significantly correlated with rsFC across the SCN, and rsFC fully mediated the relationship between gray matter covariance and structural connectivity in the nonmaltreated group. A unique association of gray matter covariance with structural connectivity was detected among individuals with a history of CM. Perturbation of gray matter development across the DMN and frontoparietal network following CM may have significant implications for mental well-being, given the networks' roles in self-referential activity. Cross-modal comparisons suggest that reduced gray matter following CM could arise from deficient functional activity earlier in life.