The first rule of fight club is “you do not talk about fight club,” but the first rule of mouse fight club seems to be “publish your results in Nature.” A team of Princeton neuroscientists recently set up a kind of sparring camp for lab mice to find out how watching a fight influenced their behavior. The team split the animals (all males) into three different groups: fighters, spectators, and novices. For the next eight days, each group engaged in a training regimen of sorts.
The fighters sparred against a weaker opponent, the spectators watched two other mice fight, and the novices enjoyed a little play session with a mouse-shaped stuffed toy. Read more: “What Darwin Overlooked About Fighting Female Animals” Then it was time to get in the octagon. All the experimental mice had to endure three four-minute rounds with an opponent who was no pushover.
During the training and fights, god-like entities (okay, the neuroscientists) watched from above, filming their behavior. Just like us, the team found that mice were enthralled by fights. Even if an attack starts and they’re not oriented, they’re more likely than chance to turn and watch what’s happening, so there’s something very salient and sticky about aggression that’s different from other behaviors.” Watching the fights seemed to benefit the spectators when it was their turn in the ring.
Both the spectators and the fighters were quicker on the attack and less likely to turn their backs than the novices. Interestingly, the time spent attacking was the same for all groups, suggesting that watching and fighting didn’t make those mice any more aggressive than the novices overall. Of course, organizing a mouse fight club was the entire point of the experiment.
The mice were genetically engineered with excitatory neurons that glowed green and inhibitory neurons that glowed red when they fired. To take a peek under the neural hood, the researchers inserted microthin fiber optic filaments into regions of their brains and watched the light show. When they viewed the fights, spectators’ inhibitory neurons fired like a fighter’s, but their excitatory neurons looked more like novice’s.
Over the course of eight days, inhibitory cells surrounding aggression hubs eased up in both fighters and spectators. When the researchers tinkered with their neural activity to boost inhibition, these more experienced pugilists suddenly fought like novices again. And according to the team, it might be possible to run the experiment in reverse.
Extract — continue reading at the source.
