It is well known that violent adults often have a history of childhood psychological trauma. Some of these individuals exhibit very real, physical alterations in a part of the brain called the orbitofrontal cortex. Yet a direct link between such early trauma and neurological changes has been difficult to find, until now.
Publishing in the January 15 edition of Translational Psychiatry, EPFL Professor Carmen Sandi and team demonstrate for the first time a correlation between psychological trauma in pre-adolescent rats and neurological changes similar to those found in violent humans.
"This research shows that people exposed to trauma in childhood don't only suffer psychologically, but their brain also gets altered," explains Sandi, Head of EPFL's Laboratory of Behavioral Genetics, Director of the Brain Mind Institute, and a member of the National Centers for Competence in Research SYNAPSY. "This adds an additional dimension to the consequences of abuse, and obviously has scientific, therapeutic and social implications."
The researchers were able to unravel the biological foundations of violence using a cohort of male rats exposed to psychologically stressful situations when young. After observing that these experiences led to aggressive behavior when the rats reached adulthood, they examined what was happening in the animals' brains to see if the traumatic period had left a lasting mark.
"In a challenging social situation, the orbitofrontal cortex of a healthy individual is activated in order to inhibit aggressive impulses and to maintain normal interactions," explains Sandi. "But in the rats we studied, we noticed that there was very little activation of the orbitofrontal cortex. This, in turn, reduces their ability to moderate their negative impulses. This reduced activation is accompanied by the overactivation of the amygdala, a region of the brain that's involved in emotional reactions." Other researchers who have studied the brains of violent human individuals have observed the same deficit in orbitofrontal activation and the same corresponding reduced inhibition of aggressive impulses. "It's remarkable; we didn't expect to find this level of similarity," says Sandi.
The scientists also measured changes in the expression of certain genes in the brain. They focused on genes known to be involved in aggressive behavior for which there are polymorphisms (genetic variants) that predispose carriers to an aggressive attitude, and they looked at whether the psychological stress experienced by the rats caused a modification in the expression of these genes. "We found that the level of MAOA gene expression increased in the prefrontal cortex," says Sandi. This alteration was linked to an epigenetic change; in other words, the traumatic experience ended up causing a long-term modification of this gene's expression.
Finally, the researchers tested the efficacy of an MAOA gene inhibitor, in this case an anti-depressant, to see if it could reverse the rise in aggression induced by juvenile stress, which it did. Going forward, the team will explore treatments for reversing physical changes in the brain, and above all, attempt to shed light on whether some people are more vulnerable to being effected by trauma based on their genetic makeup.
"This research could also reveal the possible ability of antidepressants—an ability that's increasingly being suspected—to renew cerebral plasticity," says Sandi.
Ecole Polytechnique F�d�rale de Lausanne: http://www.epfl.ch/index.en.html
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Is there a conscious generosity in how ravens or bats share food, or monkeys or elephants save others, or is it simply the selfish instinct of group survival?
DNA research into early canine remains also raises clues about migration patterns of ancient humans
Research on 85 families finds less than a third of siblings with autism carry the same genetic risk, and in nearly 70% of cases known contributory mutations do not overlap
Flanked by curious fish and tended by a diver, these coral nurseries off the coast of the Florida Keys are being grown as transplants for damaged reefs
If we could turn back the clock millions of years, would animals evolve in the same way? Genome data suggests that their options would be limited
Ah, motherhood. I don’t know anything about it, but I heard there’s a lot of, like, sacrifice and stuff. Not only do you have to bring the brat into the world, but then you have to feed it for at least 18 years or you get in big trouble. That’s a lot of pressure.
It’s three in the morning in South Africa, in the middle of winter. Temperatures have dropped to just …
A jellyfish tagging study reveals the creatures' ability to swim against the current when forming their submarine swarms, say researchers.
Size isn't everything. When many male mice mate with the same females, their descendants evolve testes that can produce more sperm
Along the seashore, harmful blooms caused by an organism called Sea Sparkle choke ecosystems but look positively enchanting