Researchers have unlocked the puzzle behind why alcohol triggers aggression, thanks to MRI, the Telegraph reported this week.

In a study published in Cognitive, Affective & Behavioral Neuroscience, researchers recruited 50 young men, half of whom were given vodka drinks and half of whom were served alcohol-free placebos. The scientists, led by Thomas Denson of the University of New South Wales in Australia, studied the participants’ reactions to being provoked while lying in an MRI machine.

Although being provoked didn’t seem to have much of an impact on the participants’ brains, the alcohol did—as few as two drinks led to decreased activity in the prefrontal cortex, which is responsible for tempering aggression.

“Although there was an overall dampening effect of alcohol on the prefrontal cortex, even at a low dose of alcohol we observed a significant positive relationship between dorsomedial and dorsolateral prefrontal cortex activity and alcohol-related aggression,” Denson told the Telegraph. “These regions may support different behaviors, such a peace versus aggression, depending on whether a person is sober or intoxicated."

Read the Telegraph’s full report here: