Psychiatrists have long known that child abuse increases a person's lifetime risk of psychiatric illness, including depression and suicide. New research by Naguib Mechawar and Gustavo Turecki from the McGill Group for Suicide Studies offers some explanation of the process through which abuse lastingly modifies brain wiring. Their research, which compare the brains of depressed suicides with or without a history of severe child abuse, and of healthy controls, identified important modifications in the Anterior Cingulate Cortex (ACC), a brain region critical for the regulation of moods and emotions. These findings were presented at the 2018 Canadian Neuroscience Meeting, in Vancouver, May 14th, 2018.
"Our results demonstrate that gene expression is strongly altered in a class of cells called oligodendrocytes in the ACC. This class of cells is responsible for producing myelin, which is an insulating compound that can be likened to the coating on electrical wires. Myelin-coated axons transmit nerve impulses efficiently, while a loss of myelin is generally associated with loss of transmission efficiency" explains Dr. Mechawar.
Using state-of the-art microscopy techniques, the researchers were able to measure the thickness of the myelin layer on individual neurons, and found that this layer was specifically thinner in brain samples from individuals having suffered from child abuse.
"Our data clearly shows how severe child abuse modifies the architecture of the ACC by affecting the formation of the myelin sheath around neurons. This modification in a region that is key for mood regulation may underlie the increased vulnerability of abused individuals to mood disorders, such as depression", concludes Dr. Mechawar.