Child abuse affects brain wiring

https://www.eurekalert.org/pub_releases/2017-09/mu-caa092517.php

Public Release: 25-Sep-2017
Child abuse affects brain wiring
Impaired neural connections may explain profound and long-lasting effects of traumatic experiences during childhood
McGill University

• For the first time, researchers have been able to see changes in the neural structures in specific areas of the brains of people who suffered severe abuse as children.
• Difficulties associated with severe childhood abuse include increased risks of psychiatric disorders such as depression, as well as high levels of impulsivity, aggressivity, anxiety, more frequent substance abuse, and suicide.
• Severe, non-random physical and/or sexual child abuse affects between 5-15 % of all children under the age of 15 in the Western world.
• 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.

For the optimal function and organization of the brain, electrical signals used by neurons may need to travel over long distances to communicate with cells in other regions. The longer axons of this kind are generally covered by a fatty coating called myelin. Myelin sheaths protect the axons and help them to conduct electrical signals more efficiently. Myelin builds up progressively (in a process known as myelination) mainly during childhood, and then continue to mature until early adulthood.

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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.

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