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BOB HIRSHON (host):
Calming the savage mouse. I’m Bob Hirshon and this is Science Update.
Take healthy male mice raised alone and activate the attack center of their brains’ hypothalamus, and they turn into enraged fighting machines.
NIRAO SHAH (Stanford University):
So they will attack males more violently, they will also attack females, which they normally never do…
HIRSHON:
That’s Stanford University neurobiologist Nirao Shah.
SHAH:
They even attack if you castrate them, so there’s no circulating sex hormones anymore.
HIRSHON:
Now, he and his colleagues report in the journal Neuron that if those mice are raised with other mice, in social environments, they respond differently. Put one of them in another male’s cage, activate its attack neurons and… nothing happens. Shah says he was astounded that social conditions could calm such a powerful biological impulse. Since humans have analogous brain regions, Shah says the work could inform research into human aggression. I’m Bob Hirshon, for AAAS, the science society.
Story by Bob Hirshon