Mice Brought to Violent Rage By Brain Adjustment, Says Study

Mice can go from 0 to 60, rage-wise, when scientists adjust a certain structure in their brains. Learning the origins of this rage and how it connects with other brain areas might later have findings for human anger, too.

The mouse brain area that we mean is called the lateral septum, which is linked to areas of the brain that manage emotions, aggression, learning and hormone production.

For mice, damage to this area can bring about all kinds of tumult in brain regions that have to do with "septal rage." In other words, it stimulates harsh attacks, generally on other mice. In mice and in some birds, this reaction when the lateral septum is damaged has been noted by scientists for a long time.

"Our latest findings show how the lateral septum in mice plays a gatekeeping role, simultaneously ‘pushing down the brake' and ‘lifting the foot off the accelerator' of violent behavior," Dayu Lin at New York University.and senior investigator on the study, said in a release.

While septal rage is not known as a human occurrence, Lin notes that learning more about male mice aggression might provide clues to the brain circuitry having to do with other aggression, such as humans' violent actions.

The study learned, for one thing, that if scientists stimulated brain cells in the lateral septum, doing so had an effect on other brain cells, such as those in a central area of the hypothalamus. This area is called the ventrolateral section of the ventromedial hypothalamus.

Scientists surgically inserted a probe that brought light to certain groups of brain cells, learning that the lateral septum's cells changed action as a result. The researchers were able to stimulate, halt and re-start the study mice's aggressive outbursts.

The study learned too that the connection between the two brain areas did not have an effect on the mice's sexual behavior. That's an important finding, Lin said in a statement, because it shows that aggression and sexual behavior can be affected or adjusted separately.

The study findings were recently reported in the journal Cell Biology.

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