A stimulating environment keeps the “hippocampus” – which is the brain’s memory control center – young, so to speak. The causes of this are molecular mechanisms that affect the regulation of genes. These current findings from studies in mice provide clues as to why an active and varied life can help maintain the mental health of the elderly. Researchers from the DZNE and the Center for Regenerative Therapies Dresden (CRTD) at the Technische Universität Dresden discuss this in the journal Nature Communication.
Human DNA – and this also applies to mice – contains thousands of genes. However, it is not only the genetic scheme that is decisive for the functioning of a cell and whether it is healthy or not, but above all which genes can be turned on or off. Aging, living conditions and behavior are known to influence this ability to activate genes. The phenomenon, called “epigenetics”, was at the center of the present study. For this, researchers including Dr Sara Zocher and Pr Gerd Kempermann examined mice that had grown up in different environments: a group of animals experienced, from an early age, an environment “enriched” with toys and toys. tunnel tubes. Rodents of a second group did not have such professional opportunities.
When the scientists examined the genome, they found that in mice that grew up in a stimulating environment, there was, with age, only a relatively small change in certain chemical DNA labels. In mice in the low stimulus environment, these changes were much more pronounced – in comparison between young and older animals. “We recorded so-called methyl groups, which stick to DNA,” explains Gerd Kempermann, lecturer at the DZNE site in Dresden, head of the DZNE research group and also a scientist at the CRTD. “These chemical bonds do not alter genetic information per se. On the contrary, they influence whether individual genes can be turned on or not.”
Such “epigenetic marks” tend to decrease with age, but in animals with stimulating living conditions, the decrease in methyl groups was comparatively small. Thus, in old mice raised in a varied environment, gene activity had somehow remained young. In particular, this affected a series of genes relevant for the growth of new neurons and cellular connections in the hippocampus. “Epigenetically, these animals retained a younger hippocampus,” Kempermann explains. Consequently, the brains of these mice were more malleable – experts speak of greater “neuroplasticity” – than in congeners of the same age who had grown up in a low stimulus environment.
The present study did not include behavioral experiments. However, Kempermann points out that many other studies have shown that mice raised in high stimulus environments perform better on memory tests than those from low stimulus environments. “It is fair to assume that this mental form is due to the stabilization of the methylation patterns that we have observed,” explains the neuroscientist. “Of course, the question is to what extent our results also apply to humans. Here the situation is likely to be more complicated. After all, it is a question of how living conditions influence behavior. and the way humans respond to external stimuli is much more complex than in mice. However, we have good reason to believe that the basic epigenetic principles are the same in humans as in mice. “
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Materials provided by DZNE – German Center for Neurodegenerative Diseases. Note: Content can be changed for style and length.