“ (In) individuals have a natural tendency to behave aggressively…The communications between the amygdala and the prefrontal cortex was weaker….Weak’ communications means that it is more difficult for the prefrontal cortex to control the feelings of anger that are generated.”
- Fluctuations of serotonin levels in the brain, which often occur when someone hasn’t eaten or is stressed, affects brain regions that enable people to regulate anger
- When serotonin levels are low, it may be more difficult for the prefrontal cortex to control emotional responses to anger
- that it is more difficult for the prefrontal cortex to control the feelings of anger that are generated
Serotonin levels affect the brain’s response to anger
- “We’ve known for decades that serotonin plays a key role in aggression, but it’s only very recently that we’ve had the technology to look into the brain and examine just how serotonin helps us regulate our emotional impulses. By combining a long tradition in behavioral research with new technology, we were finally able to uncover a mechanism for how serotonin might influence aggression.”” Dr Molly Crockett, University of Cambridge, University of Zurich)
Reduced serotonin levels have previously been implicated in aggression, this is the first study which has shown how this chemical helps regulate behaviour in the brain as well as why some individuals may be more prone to aggression.
The research revealed that:
- Low brain serotonin made communications between specific brain regions of the emotional limbic system of the brain and the frontal lobes weaker
- Compared to those present under normal levels of serotonin
Findings suggest that when serotonin levels are low, it may be more difficult for the prefrontal cortex to control emotional responses to anger that are generated within the amygdala.
They also determined which individuals have a natural tendency to behave aggressively. In these individuals:
- The communications between the amygdala and the prefrontal cortex was even weaker following serotonin depletion
- ‘Weak’ communications means that it is more difficult for the prefrontal cortex to control the feelings of anger that are generated
- As a result, those individuals who might be predisposed to aggression were the most sensitive to changes in serotonin depletion.
“These results came from healthy volunteers, they are also relevant for a broad range of psychiatric disorders in which violence is a common problem. For example, these results may help to explain the brain mechanisms of a psychiatric disorder known as intermittent explosive disorder (IED). Individuals with IED typically show intense, extreme and uncontrollable outbursts of violence which may be triggered by cues of provocation such as a facial expression of anger.”