New research shows how bullying activates reward circuits.
Aggressive behavior is often a facet of psychiatric disorders. But it also readily occurs in people with no such condition.
Bullying has the potential to significantly reduce the victim's quality of life. As such, it is a topic well worthy of study.
According to the American Society for the Positive Care of Children, 28 percent of students aged 12-18 report being bullied at school.
There has been a great deal of study into the psychological and social reasons behind bullying. As neuroscience grows in strength, new findings are also adding to our knowledge about how and why bullying takes place.
Researchers now believe that aggressive behavior is associated with an inappropriate activation of the brain's reward system.
A recent study, conducted at Icahn School of Medicine at Mount Sinai, investigated the neural correlates of bullying-type behavior in mice.
The research, published in Nature and headed up by Scott Russo, Ph.D., associate professor of Neuroscience, took a new approach to areas of the brain known to be involved in aggressive behavior - the basal forebrain and the lateral habenula circuit.
Aggressive mouse model
Earlier work has implicated the basal forebrain as an important region for aggression-related behaviors. The present study went one step further; the investigators looked at how its connections to other brain areas affect aspects of aggression.
"Our study is the first to demonstrate that bullying behavior activates a primary brain reward circuit that makes it pleasurable to a subset of individuals. Furthermore, we show that manipulating activity in this circuit alters the activity of brain cells and ultimately, aggression behavior."
Scott Russo, Ph.D.
To study the activity of the basal forebrain in aggression, the team used a mouse model. This involved introducing a young, subordinate mouse to an adult male for 3 minutes each day for 3 consecutive days.
Under these conditions, Tim Newman (resource no longer available at www.nature.com)