Researchers at the University of California, Berkeley recently discovered that chronic stress can catalyze long-term changes in the human brain. This could help explain why those that suffer from chronic stress are more likely to become victim to other mental issues like anxiety and mood disorders. These remarkable findings could lead therapists and counselors to develop new techniques to reduce the risk of developing any form of mental illness after stressful events occur.
It has already been a known fact that those with stress-related illnesses like post-traumatic stress disorder (PTSD) develop abnormalities in the brain. This can include an unequal amount of gray matter and white matter. While gray matter is made up of mostly cells that store and help process information, white matter is made up of axons. The axons help create fibers that connect neurons to each other. There is a white, fatty myelin sheath surrounding axons, which is where white matter gets its name. This myelin sheath accelerates the flow of electrical signals between cells.
Researchers and medical professionals are just beginning to uncover the secret as to how stress catalyzes long-lasting changes in the brain structure. For example, Daniela Kaufer, associate professor of integrative biology at UC Berkeley, conducted a set of experiments which helped discover that chronic stress actually produces more myelin-producing cells while producing fewer neurons than is normal for the body. As a result, there is an excess of myelin in the body, which also results in more white matter in some parts of the brain. In turn, this disrupts the balance as well as the way information is communicated in the brain. Kaufer mentioned that the study only looked at the hippocampus, but that the findings could help prove that white matter changes under various mental conditions such as autism, depression, suicide, schizophrenia, ADHD, and PTSD. The hippocampus is known to regulate memory as well as emotions. It plays a role in myriad emotional disorders.
The question remains: Can stress affect connectivity within the brain? It seems that Kaufer’s findings infer that changes in brain connectivity can occur among those who suffer from PTSD and other disorders.
It is possible, according to Kaufer, for PTSD patients to develop a much stronger connection between the hippocampus and the brain’s fight or flight response, which is the amygdala. A strong connection in this area could mean that a person’s fear responses are quicker than normal, which is often seen in stress survivors.
While this is taking place, the connectivity between the hippocampus and the part of the brain that moderates our responses, the prefrontal cortex, is found to be lower than normal for these patients. When these connections are not as strong as they should be, a person’s ability to dampen their response is limited significantly. In other words, if someone finds themselves in a stressful environment, the signals between the brain that usually tell him or her to not stress out don’t work as they normally should. Currently, Kaufer is testing this particular hypothesis in PTSD patients. In addition, she continues to look at brain changes in rodents that are subject to chronic stress at an early stage of life.
Does stress change stem cells?
Kaufer’s research looked at the cellular and molecular effects that acute and chronic stress have on the body. She focused this particular study on the hippocampus in brains of adult rats, looking specifically at neural stem cells. Typically, these stem cells were historically considered to mature into neurons or astrocytes, which are a type of glial cell. Kaufer’s research uncovered, though, that chronic stress caused stem cells in this part of the brain to evolve into a different type of glial cell, namely the oligodendrocyte. This cell is known for producing the myelin, which sheaths nerve cells.
This finding means that oligodendrocytes play a key role in the long-term and sometimes permanent changes in a person’s brain that might trigger mental problems down the road. In addition, because chronic stress also changes the amount of stem cells that become neurons, it is possible that chronic stress plays a role in changing learning and memory.
At the moment, research is ongoing into how stress in infancy can affect the white matter in the brain. This will help uncover whether chronic early-life stress diminishes resilience at a later stage of life. In addition, researchers are looking at the effects of certain therapies like exercise and antidepressant drugs, which can reduce the role stress plays in the brain. Overall, Kaufer’s research is quite remarkable and could mean some dramatic changes in the way stress is treated by medical professionals.