Nav: Home

Bats' brains sync when they socialize

June 20, 2019

Berkeley -- The phrase "we're on the same wavelength" may be more than just a friendly saying: A new study by University of California, Berkeley, researchers shows that bats' brain activity is literally in sync when bats engage in social behaviors like grooming, fighting or sniffing each other.

"Whenever the bats were socially interacting, you could see these very robust correlations in brain activity," said Michael Yartsev, an assistant professor of neurobiology and bioengineering at UC Berkeley.

This study, appearing June 20 in the journal Cell, is the first to observe synchronized brain activity in a non-human species engaging in natural social interactions. The finding opens the door to future study on how our brains process social interactions and has potential implications for understanding diseases, like autism, that affect social behavior.

"This is a very core phenomenon that, for two decades, people have been excited about in humans," Yartsev said. "Now that we've observed it in an animal model, it opens the door to very detailed research of it."

While some correlations have been found between brain activity in socializing humans, human studies have been limited to using brain imaging techniques, such as functional magnetic resonance imaging (fMRI), which does not measure electrical activity directly, or electroencephalography (EEG), which is typically limited to measuring low frequency brain waves.

In the study, Yartsev and Berkeley postdoctoral scholar Wujie Zhang used wireless neural recording devices to measure the brain activity of Egyptian fruit bats while the bats freely interacted in a chamber. The researchers' recording devices allowed them to capture what fMRI and EEG techniques cannot -- signals that include the bats' higher frequency brain waves, as well as electrical activity from individual neurons.

They found surprisingly strong correlations between the bats' brains, especially for brain waves in the high frequency band. These correlations were present whenever the bats shared a social environment and increased before and during their social interactions.

"The inter-brain correlations were so strong that you could easily see them in the raw data," Zhang said. "This is the first time in my career where a result was so robust that it popped out from the data like that."

To better understand these correlations, a team of undergraduate assistants went frame-by-frame through hours of high-speed video of the bats, characterizing their behavior in each frame. Zhang and Yartsev then analyzed the relationship between bat behavior and inter-brain correlation.

Their detailed analysis allowed them to rule out other possible explanations for the synced-up brain activity, such as that the bats' brains were simply reacting to the same environment, or that the bats were engaging in the same behavior. For example, two bats placed in identical, but separate, chambers and both busy grooming did not show the same synchronization.

The inter-brain synchronization was really all about sharing a social experience together, Yartsev said. Even when three bats shared the same social environment, but only two of them were actively interacting with each other, the brains of all three were synchronized.

"It's kind of like, if you think about a dinner table, some people could be talking back and forth, while another person would be sitting there, still paying attention, while still being part of the social interaction," Yartsev said. "Under that analogy, then, supposedly all of the brains would be correlated simultaneously."

There is still much to be revealed about just what this high frequency band of brain waves does, though there is some evidence that it is involved in a number of mental processes that would be needed to successfully navigate a dinner party -- including sensory and emotional information-processing, attention and working memory.

And while being "on the same wavelength" may seem a little magical or mysterious, the researchers stress that it is anything but.

"One of the explanations of this is that, when you and I are interacting, we are basically forming a closed loop," Yartsev said. "I am doing a bunch of motor actions, such as articulating words, and you are hearing them, and you are processing them, and then you are making ongoing, on-the-fly decisions about how to react to them. And I respond in exactly the same way to you. This loop between us is what likely leads to brains getting linked to one another and is an important aspect of the ability to engage in successful social interactions."

"The 'magic' here is social interaction," Zhang added. "When we interact, our brains engage each other indirectly through our behaviors."
This research was supported by the National Institutes of Health (DP2-DC016163), the New York Stem Cell Foundation NYSCF-R-NI40, the Alfred P. Sloan Foundation (FG-2017-9646), the Brain Research Foundation (BRFSG-2017-09), the National Science Foundation (NSF- 1550818), the Packard Fellowship (2017-66825), the Klingenstein-Simons Fellowship, the Pew Charitable Trust (00029645) and the Dana Foundation.

University of California - Berkeley

Related Brain Activity Articles:

How dopamine drives brain activity
Using a specialized magnetic resonance imaging (MRI) sensor that can track dopamine levels, MIT neuroscientists have discovered how dopamine released deep within the brain influences distant brain regions.
Brain activity intensity drives need for sleep
The intensity of brain activity during the day, notwithstanding how long we've been awake, appears to increase our need for sleep, according to a new UCL study in zebrafish, published in Neuron.
Do babies like yawning? Evidence from brain activity
Contagious yawning is observed in many mammals, but there is no such report in human babies.
Understanding brain activity when you name what you see
Using complex statistical methods and fast measurement techniques, researchers found how the brain network comes up with the right word and enables us to say it.
Your brain activity can be used to measure how well you understand a concept
As students learn a new concept, measuring how well they grasp it has often depended on traditional paper and pencil tests.
Altered brain activity in antisocial teenagers
Teenage girls with problematic social behavior display reduced brain activity and weaker connectivity between the brain regions implicated in emotion regulation.
Gender impacts brain activity in alcoholics
Compared to alcoholic women, alcoholic men have more diminished brain activity in areas responsible for emotional processing (limbic regions including the amygdala and hippocampus), as well as memory and social processing (cortical regions including the superior frontal and supramarginal regions) among other functions.
Light, physical activity reduces brain aging
Incremental physical activity, even at light intensity, is associated with larger brain volume and healthy brain aging.
Measuring brain activity in milliseconds possible through new research
Researchers from King's College London, Harvard and INSERM-Paris have discovered a new way to measure brain function in milliseconds using magnetic resonance elastography (MRE).
Autism: Brain activity as a biomarker
Researchers from Jülich, Switzerland, France, the Netherlands, and the UK have discovered specific activity patterns in the brains of people with autism.
More Brain Activity News and Brain Activity Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at