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This is Scientific American — 60-Second Science. I'm Erika Beras.
Got a minute?
In recent years researchers have learned that trauma can be inherited—passed down due to changes in DNA, what's known as epigenetics. But researchers recently uncovered a new wrinkle to the story:
"The effects of trauma which can be transmitted to the offspring can be reversed by a positive experience."
That's Isabelle Mansuy, professor of neuroepigenetics at the University of Zurich.
She and colleagues studied newborn male mice and their mothers that were separated from each other, which caused them both to experience traumatic stress. Those male mice and their male offspring displayed trauma symptoms—which made them different from other mice that had not been separated from their mothers. But when these symptomatic mice were exposed to positive experiences, their behavior changed—as did the fate of their offspring.
"And we show that the negative consequences of this which are depressive behaviors, cognitive problems, antisocial behaviors, risk-taking, this can be reversed if the father after being traumatized was exposed to a positive environment. So this reverses the symptoms and it also reverses the biological reasons, the biological cause for the symptoms in the progeny which are the epigenetic marks. Epigenetic marks can be corrected in sperm cells by this positive experience."
The study was in the journal Neuropsychopharmacology.
Mansuy says the behavioral changes were associated with an increased level of the glucocorticoid receptor in the hippocampus—the part of the brain that contributes to stress responses. And these alterations were found in the hippocampus of the traumatized fathers—and of their offspring.
This is the first evidence that positive environmental surroundings can correct behavioral alterations that could otherwise be passed down. In this case, via epigenetic regulation of the glucocorticoid receptor gene.
Typically, drugs would be used to try to effect this kind of change. Mansuy says this work could change that.
"There is hope, that even people who have been traumatized during childhood and have severe symptoms, psychiatric symptoms or other metabolic symptoms or other problems with the body that this can be reversed at some point. So even if there is engraved in the epigenome in a way this is the system, the biology is dynamic enough to allow correction."
Thanks for the minute for Scientific American — 60-Second Science Science. I'm Erika Beras.
