Brains of mice and bats could help researchers understand human interactions

Mice Photo by Shutterstock/Stephen Clarke

Heading to the cottage with your extended family this summer? New research on group behaviour of bats and mice (no strangers to the cottage) may help your weekend go smoother. 

On June 20, two separate studies published in the journal Cell proved that the neural activity in mice and bats’ brains synchronize when they interact with their own kind. This synchronicity then determines their social behaviour. 

When bats interacted with other bats or mice with other mice, whether it be grooming themselves, fighting, or resting, the rhythm of their brain activity synced up. But when the animals were separated, their brain activity was no longer in sync. “They’re like wireless signals going back and forth,” says Weizhe Hong, an assistant professor in the biological chemistry department at UCLA and one of the lead researchers on the mouse paper.

The real question, however, is: Do humans’ brains also synchronize during social interactions?

Too often, a weekend at the cottage brings together a whole variety of personalities: chatty cousins, lazy uncles, outdoorsy friends. But how easy is it to coerce that lazy uncle into a forest hike, or that outdoorsy friend into a day on the dock eating chips? Easier than we thought. According to Hong, human brains do, in fact, synchronize during social interactions. This synchronicity allows us to better understand one another during conversations or other social behaviours.

Previously, researchers primarily studied the activity of a single brain and how it dictated behaviours such as eating, drinking, and walking. But Hong’s study has delved into the field of social behaviour, which “is very different because it involves two or more individuals who are behaving together,” he says.

The synchronicity of the brains is dependent on the hierarchical relationship between the two animals. Animals with more dominant personalities influenced how the other animals behaved in social interactions. Hong explains that this is because dominant animals care more about their own behaviour than the subordinate animal’s, and the subordinate animal will care more about the behaviour of the dominant animal. “The synchronization between the two brains are significantly higher when dominant animals behave,” Hong says. (No surprise to cottagers who share a space with family members who always call the shots.) But if the two brains don’t sync, it’s likely because the individuals are either both dominant or both subordinate. 

When the animals’ brains were in sync, their social behaviours also matched, with the subordinates following the lead of the dominant animal as it groomed or rested. Perhaps this explains why some weekends people just do their own thing separately, and other times everyone seems to swim at the same time, or go for a walk, or retreat in the afternoon for a nap. 

The synchronicity of the animals’ brains also predicted future social interactions. “If the two animals are more synchronized with each other then they’re more likely to behave or interact with each other in the near future,” Hong says. When you’re in synch, you may be more likely to get together during the week, or to score a repeat cottage invite. 

Moving forward, Hong plans on applying this research to the human brain. He says this could have a significant impact on mental illness and mental disorders, such as autism and schizophrenia. “Social interactions are one of the most prominent, most important deficits across the board in mental disorders,” Hong says. The team plans on investigating how the brain affects social interactions, particularly in people who struggle with social behaviours. “We can really learn about the nature of the illness and the psychiatric symptoms, so we can develop ways to tackle those fundamental issues.”

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