Brain genes determine the stress processing

The effects of stress in the brain are predetermined by the genes

08/18/2014

According to the results of a recent study by the MedUni Vienna, susceptibility to stress is largely determined by the genes. „Our genes determine which traces leave stress in the brain“, so the message of the MedUni. The individual genetic conditions are directly related to the effect of stress on our emotional centers, reports the research team led by study leader Lukas Pezawas. Their results have the scientists in the renowned trade magazine „Journal of Neuroscience“ released.

Stress can have extremely different effects on people, because not every person reacts immediately to life events of equal importance, according to the MedUni Vienna. „Some develop through crises, but others break and suffer from depression, for example“, the researchers write. These individual differences would „determined by a complex interplay of depressive gene variants and environmental factors.“ The scientists of MedUni, according to their own information, together with international cooperation partners have succeeded in demonstrating this for the first time, „that there are interactions between stressful life events and certain risk gene variants, which subsequently change the volume of the hippocampus sustainably.“

Stressful life events affect the hippocampus
The hippocampus is an essential „Switching station in the emotion processing and is considered a central interface in the stress processing“, explain Pezawas and colleagues. From previous studies it was already known that this brain region is very sensitive to stress. „In stress, which is interpreted as a danger to the organism ('distress'), it loses volume, which is often observed in depressive patients and is responsible for some of the clinical symptoms“, reports the MedUni Vienna. However, in return, could „positive stress ('Eustress'), as it occurs in emotionally stimulating social situations, even lead to an increase in volume of the hippocampus.“ The effect of stressful life events on the size of the hippocampus, however, does not exclusively depend on environmental factors, but determines the genes, according to current study results, „whether the same life event leads to an increase or decrease in hippocampal volume“

Genes with significant influence on stress management
According to the findings of the researchers is thus determined by the genes, „if the stress is good or bad for our brain.“ The more risk genes a human possesses, the more negative impact on the size of the hippocampus from adverse life events, reports the research team led by Lukas Pezawas. „With no or only a few risk genes, this life event can even have a positive effect“, the researchers write further. Initially, the scientists had their study at the Department of Psychiatry and Psychotherapy at MedUni Vienna „Life events such as deaths in the family, divorces, job loss, financial losses, relocation, serious illnesses or accidents are quantified in healthy volunteers.“ Subsequently, a high-resolution anatomical magnetic resonance tomography of the brain was performed to determine the hippocampus volume. The researchers also compared the genetic data obtained.

Stress can also have a stimulating effect on the brain
This showed that „Persons with the three gene variants considered to be depressing had a smaller hippocampus in a similar number of stressful life events than those with fewer or none of these gene variants“, explained study leader Lukas Pezawas. By contrast, people with only one or none of these risk genes would have an enlarged hippocampus in similar life events. On her brain seemed the stress apparently stimulating. The researchers conclude that the study results confirm the importance of gene-environment interactions as a determinant of hippocampal volume. „These findings are important in understanding neurobiological processes in stress-associated diseases such as depression or post-traumatic stress disorder“, reports study director Pezawas. „It is our genes that ultimately set the course, whether stress makes us mentally ill or promotes our mental health.“, Pezawas continues. (Fp)