Prolonged stress degrades synapses, whose role is to link neurons to other nerve cells. Laboratory experiments have shown that this phenomenon is associated with motor disorders.
- Chronic stress is linked to prolonged exposure to anxiety-provoking events.
- People with chronic stress often have motor disorders of varying severity.
- The researchers assume that the synapses are degraded by immune cells in response to stress.
It is difficult to escape stress, whether in personal or professional life. For some people, it is even complicated to get out of it, but when it becomes chronic, it can be dangerous for your health. In the review Translational psychiatry, scientists from the German University of Bonn explain that it can degrade the brain. They found this out in a study on mice.
Photographs of mouse brains
During this work, the researchers used mice as laboratory animals, some of which were exposed to a stressful situation for a few days. Throughout their research, they used a special microscopy method to take pictures of rodent brains, including parts of the cerebral cortex dedicated to motor control and learning new movements. “With our method, it is possible to observe one and the same neuron at different times.says Dr Anne-Kathrin Gellner, doctor in the department of psychiatry and psychotherapy at the University Hospital of Bonn. So we can see how it changes depending on the stress.“
Motor disorders, even in resilient animals
Thanks to this technique, they noticed that after exposure to stress, neurons change: they lose some of their synapses, whose role is to make the link with other nerve cells. Stressed rodents lost up to 15% of their synapses. In parallel, the mice showed motor learning deficits. For example, they had to try to grab a pellet of food with one paw and carry it in their mouth. In the wild, mice use both legs to achieve this, so they had to relearn this skill. The unstressed control group had a 30% success rate after five days. For the stressed rodents, it took ten attempts each time for them to succeed. The researchers also noticed that the resilient mice, those that displayed no symptoms despite exposure to stress, also had difficulty grasping the pellet with one paw. “It is therefore possible that motor tests are suitable for detecting stress-related disorders such as depression before other symptoms appear.“, assumes Professor Valentin Stein, co-author of the study. The researcher believes that psychological stress could create permanent damage in the brain, due to the inability of the affected neurons to recreate synapses.
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