Long-term stress can lead to memory loss, a new study has found. Researchers also discovered that the immune system has a crucial role to play in cognitive damage.
Researchers from the Ohio State University conducted a mice study that could eventually lead to new treatments for long-term, repetitive mental attacks. These types of mental assaults can affect soldiers, victims of bullying, those who report to difficult bosses and more.
Ohio State's neuroscience associate professor Jonathan Godbout referred to type of mental attacks as chronic stress, adding that it is not the kind associated with meeting a new person or speaking in public. Godbout's research is the first to analyze the relationship between chronic stress and short-term memory.
In the mice study, the chronic stress was induced in the form of repetitive visits from bigger and more aggressive mice intruders. Before the "stressful" period started, the mice managed to master finding the escape hole in a maze.
The mice that were continually exposed to the bigger mice intruders had a difficult time finding the same escape hole. Godbout said that the stressed mice were not able to recall the escape route while the mice in the control group managed to remember the information.
Apart from the maze test, the research team found evidence of immune system-activated brain inflammation, which was a response to the chronic stress. The analysis of the stressed mice's brains revealed the presence of macrophages, a type of immune cell.
The researchers found that the brain inflammation and the changes in the immune system caused the short-term memory loss. Chronic stress' effect on the memory and the confirmed immune-activated brain inflammation are considered important discoveries in the field.
"It's possible we could identify targets that we can treat pharmacologically or behaviorally," explained Godbout. The findings were published The Journal of Neuroscience.
John Sheridan, the associate director of Institute for Behavioral Medicine Research in Ohio State, said that there could be methods to halt the brain inflammation. The stressed mice in the study displayed depressed-liked behaviors and social avoidance.
When the team gave the stressed mice a chemical that stops inflammation, the depressive symptoms and brain-cell problems did not fade. However, the immune cells called macrophages and memory loss problems went away.
"Stress releases immune cells from the bone marrow and those cells can traffic to brain areas associated with neuronal activation in response to stress," added Sheridan.
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