Scientists have pinpointed a group of neurons deep in the brain that make mice either want to have sex or to fight.
In fact, the researchers could switch the behavior of a single animal from mounting to attacking by gradually increasing how strongly the neurons were stimulated.
In this case, the scientists stimulated the neurons with pulses of light, a method called optogenetics. When the neurons were strongly activated, a male mouse would attack another male or a female mouse.
When the same neurons, which are located in the hypothalamus, were weakly activated, the mouse would start to sniff and mount, both mating behaviors.
Inhibiting the neurons stopped both behaviors dead in their tracks.
The findings by researchers at the California Institute of Technology are published in the journal Nature.
The neurons initially were identified because they express a protein receptor for the hormone estrogen, reinforcing the view that estrogen plays an important role in the control of male aggression, contrary to popular opinion.
Because the human brain contains a hypothalamus that is structurally similar to that in the mouse, these results may be relevant to human behavior as well.
《Scalable control of mounting and attack by Esr1+ neurons in the ventromedial hypothalamus》, Published on Journal 《nature》in April 25, 2014.