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Finding The Brain Circuits That Turn Mice Into Winners

Animals that win social showdowns are more likely to keep winning. Now, scientists think they've found the brain region that explains why.

Finding The Brain Circuits That Turn Mice Into Winners

By: Evan Thomas

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Researchers working with mice found a brain circuit that seems to lead to "alpha mice." Activating these neurons increased a mouse's chance of making rivals yield — and might help explain how natural pecking orders and other hierarchies form.

Scientists had mice butt heads in a tube and measured their brain activity while they pushed or retreated.

When researchers suppressed specific neurons, mice were less likely to push or resist and more likely to retreat. When researchers used light to continuously stimulate the neurons, mice won a lot, even against opponents they lost to.

And when researchers stopped using the light boost, the dominance effect persisted. If a mouse got enough assisted wins, they kept winning on their own.

Scientists have known about this "winner effect" for years. Animals that triumph in a social dispute are more likely to win future showdowns. This helps the fittest individuals survive: If you win a fight over food, for example, your odds of snagging the best perch also improve.

Identifying the brain circuity associated with the winner effect might help us see how personality traits like stubbornness or competitiveness show up in the brain. Researchers suggest it might help us treat personality disorders in the future.