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:

More brain activity is not always better when it comes to memory and attention
Potential new ways of understanding the cause of cognitive impairments, such as problems with memory and attention, in brain disorders including schizophrenia and Alzheimer's are under the spotlight in a new research review.
Researchers to predict cognitive dissonance according to brain activity
A new study by HSE researchers has uncovered a new brain mechanism that generates cognitive dissonance -- a mental discomfort experienced by a person who simultaneously holds two or more contradictory beliefs or values, or experiences difficulties in making decisions.
Brain activity can be used to predict reading success up to 2 years in advance
By measuring brainwaves, it is possible to predict what a child's reading level will be years in advance, according to research from Binghamton University, State University of New York.
There's a close association between magnetic systems and certain states of brain activity
Scientists from the University of Granada (UGR) have proven for the first time that there is a close relationship between several emerging phenomena in magnetic systems (greatly studied by condensed matter physicists) and certain states of brain activity.
Hormone can enhance brain activity associated with love and sex
The hormone kisspeptin can enhance activity in brain regions associated with sexual arousal and romantic love, according to new research.
More Brain Activity News and Brain Activity Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Teaching For Better Humans
More than test scores or good grades — what do kids need to prepare them for the future? This hour, guest host Manoush Zomorodi and TED speakers explore how to help children grow into better humans, in and out of the classroom. Guests include educators Olympia Della Flora and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#535 Superior
Apologies for the delay getting this week's episode out! A technical glitch slowed us down, but all is once again well. This week, we look at the often troubling intertwining of science and race: its long history, its ability to persist even during periods of disrepute, and the current forms it takes as it resurfaces, leveraging the internet and nationalism to buoy itself. We speak with Angela Saini, independent journalist and author of the new book "Superior: The Return of Race Science", about where race science went and how it's coming back.