Some people can experience unprovoked, violent outbursts that they are unable to control. But where do these fits of rage come from? A new study may offer clues.
Researchers have now found that sudden, violent behavior in male mice was associated with changes in a brain structure called the lateral septum. Furthermore, they found they could turn aggression on and off in the mice by activating certain brain cells in this region. The researchers say their findings could help us better understand what triggers aggression in other animals, including humans.
According to the researchers, the lateral septum is connected to the hippocampus — the brain region responsible for emotion and learning — and protrudes into the hypothalamus — the brain region that is closely associated with hormone production and aggression. The lateral septum also receives signals from both of these brain regions.
For their study, the researchers surgically inserted a probe into the brains of male mice, using the probe to ‘excite’ certain groups of brain cells by shining a light on them. They found that by exciting brain cells in the lateral septum, they were able to alter their activity and repeatedly start and stop violent outbursts in the male mice, known as ‘septal rage’, in which they suddenly attacked other mice.
"Our research provides what we believe is the first evidence that the lateral septum directly 'turns the volume up or down' in aggression in male mice, and it establishes the first ties between this region and the other key brain regions involved in violent behavior," the researchers said. The team added that though septal rage has not been identified in humans, they believe their findings could help pinpoint the brain circuitry involved in other forms of aggression in humans.