Child abuse affects brain wiring
September 25, 2017 by Katherine Gombay
Researchers from the McGill Group for Suicide Studies, based at the Douglas Mental Health University Institute and McGill University's Department of Psychiatry, have just published research in the American Journal of Psychiatry that suggests that the long-lasting effects of traumatic childhood experiences, like severe abuse, may be due to an impaired structure and functioning of cells in the anterior cingulate cortex. This is a part of the brain which plays an important role in the regulation of emotions and mood.
The researchers believe that these changes may contribute to the emergence of depressive disorders and suicidal behaviour....
Impaired neural connectivity may affect the regulation of emotions
The researchers discovered that the thickness of the myelin coating of a significant proportion of the nerve fibres was reduced ONLY in the brains of those who had suffered from child abuse. They also found underlying molecular alterations that selectively affect the cells that are responsible for myelin generation and maintenance. Finally, they found increases in the diameters of some of the largest axons among only this group and they speculate that together, these changes may alter functional coupling between the cingulate cortex and subcortical structures such as the amygdala and nucleus accumbens (areas of the brain linked respectively to emotional regulation and to reward and satisfaction) and contribute to altered emotional processing in people who have been abused during childhood.
The researchers conclude that adversity in early life may lastingly disrupt a range of neural functions in the anterior cingulate cortex....
More information: Pierre-Eric Lutz et al, Association of a History of Child Abuse With Impaired Myelination in the Anterior Cingulate Cortex: Convergent Epigenetic, Transcriptional, and Morphological Evidence, American Journal of Psychiatry (2017).
Association of a History of Child Abuse With Impaired Myelination in the Anterior Cingulate Cortex: Convergent Epigenetic, Transcriptional, and Morphological Evidence
Published online: July 28, 2017
Child abuse has devastating and long-lasting consequences, considerably increasing the lifetime risk of negative mental health outcomes such as depression and suicide. Yet the neurobiological processes underlying this heightened vulnerability remain poorly understood. The authors investigated the hypothesis that epigenetic, transcriptomic, and cellular adaptations may occur in the anterior cingulate cortex as a function of child abuse....
A history of child abuse was associated with cell type–specific changes in DNA methylation of oligodendrocyte genes and a global impairment of the myelin-related transcriptional program. These effects were absent in the depressed suicide completers with no history of child abuse, and they were strongly correlated with myelin gene expression changes observed in the animal model. Furthermore, a selective and significant reduction in the thickness of myelin sheaths around small-diameter axons was observed in individuals with history of child abuse.
The results suggest that child abuse, in part through epigenetic reprogramming of oligodendrocytes, may lastingly disrupt cortical myelination, a fundamental feature of cerebral connectivity.