Nav: Home

Two studies show that animals' brain activity 'syncs' during social interactions

June 20, 2019

Two papers publishing June 20 in the journal Cell show that Egyptian fruit bats and mice, respectively, can "sync" brainwaves in social situations. The synchronization of neural activity in the brains of human conversation partners has been shown previously, as a result of one person picking up social cues from the other and modulating their own behavior based on those cues. These studies now suggest that something similar occurs when animals engage in natural social interactions and find that some aspects of the animals' social behavior can be predicted based on neural observations.

"Animal models are really important for being able to study brain phenomena at levels that we can't normally access in humans," says Michael Yartsev of the Department of Bioengineering at the University of California, Berkeley, and senior author of one of the papers. "Because bats are extremely social and naturally live in highly complex social environments, they are a great model for tackling important scientific questions about social behavior and the neural mechanisms underlying it."

"If you think of the brain like a black box that receives input and gives some kind of output in response, studying social interactions is like trying to understand how the output of one box provides input to another, and how those two boxes work together and create a loop," says Weizhe Hong of the Departments of Biological Chemistry and Neurobiology at the University of California, Los Angeles, and senior author of the other paper. "Our research in mice allows us to peer inside these black boxes and get a better look at the internal machinery."

Previous studies showing how neural activity in humans becomes synchronized during social interactions have used technologies like fMRI and EEG, which look at brain activity with relatively coarse spatial and temporal resolutions. These studies found that when two people interact, structures in their brain simultaneously decode and respond to signals from the other person.

Because the new studies looked at neural activity at a level of detail that is difficult to obtain in humans, they could explore the detailed neural mechanism underlying this phenomenon.

The Berkeley team monitored the bats for sessions of about 100 minutes each as they engaged in a wide range of natural social interactions, such as grooming, mating, and fighting. The bats were filmed with high-speed cameras, and their specific behaviors and interactions were carefully characterized.

As this was happening, the scientists were using a technology called wireless electrophysiology to simultaneously record the brain activity in the bats' frontal cortices across a wide range of neural signals, ranging from brain oscillations to individual neurons and local neural populations. They saw that the brains of different bats became highly correlated and that this correlation was most pronounced in the high-frequency range of brain oscillations. Furthermore, the correlation between the brains of individual bats extended across multiple timescales of social interactions, ranging from seconds to hours. Remarkably, by looking at the level of correlation, they could predict whether the bats would initiate social interactions or not.

The UCLA team took a different tack. They used a device called a miniaturized microendoscope to monitor the brain activities of mice during social situations. These tiny devices, which weigh only two grams, are fitted on the mice and allow the researchers to monitor the activity of hundreds of neurons at the same time in both animals. They saw that mice also exhibit interbrain correlations in natural social interactions where animals freely interact with each other. Moreover, the access to thousands of individual neurons gave them an unprecedented view of both animals' decision-making processes and revealed that interbrain correlation emerges from different sets of neurons that encode one's own behavior and behavior of the social partner.

Social interactions are often nested within the context of a dominance hierarchy. By imaging two mice in a competitive social interaction, they discovered that behavior of the dominant animal drives synchrony more strongly than behavior of the subordinate animal. Remarkably, they also found that the level of correlation between two brains predicts how mice will respond to each other's behavior as well as the dominance relationships that develop between them.

"Natural social interactions are complex," says Wujie Zhang, a postdoctoral researcher in Yartsev's lab and first author of the fruit bat paper. "It is important to embrace this complexity in order to understand real-life social interactions at the neural level."

"We know that social interactions are altered in many mental diseases in human, including autism spectrum disorders and schizophrenia," says Lyle Kingsbury, a graduate student in Hong's lab and first author of the mouse paper. "Developing a genetically tractable model system opens up the possibility of exploring how interbrain synchrony is disrupted in people with these conditions and may provide novel information about possible interventions."
-end-
Cell, Zhang and Yartsev: "Correlated Neural Activity Across the Brains of Socially Interacting Bats." https://www.cell.com/cell/fulltext/S0092-8674(19)30551-3 DOI: 10.1016/j.cell.2019.05.023

This research was supported by the National Institutes of Health, the New York Stem Cell Foundation, the Packard Fellowship, the Klingenstein-Simons Fellowship, the Pew Charitable Trust, and the Dana Foundation.

Cell, Kingsbury et al: "Correlated Neural Activity and Encoding of Behavior Across Brains of Socially Interacting Animals." https://www.cell.com/cell/fulltext/S0092-8674(19)30550-1 DOI: 10.1016/j.cell.2019.05.022

This research was supported in part by the NIH, an ARCS Foundation Fellowship, a Whitehall Foundation grant, a NARSAD Young Investigator grant, a Sloan Research Fellowship, a Searle Scholars Award, a Klingenstein-Simons Fellowship Award, a Fay/Frank seed grant from the Brain Research Foundation, and a Packard Foundation Fellowship Award.

Cell (@CellCellPress), the flagship journal of Cell Press, is a bimonthly journal that publishes findings of unusual significance in any area of experimental biology, including but not limited to cell biology, molecular biology, neuroscience, immunology, virology and microbiology, cancer, human genetics, systems biology, signaling, and disease mechanisms and therapeutics. Visit: http://www.cell.com/cell. To receive Cell Press media alerts, contact press@cell.com.

Cell Press

Related Neurons Articles:

New tool to identify and control neurons
One of the big challenges in the Neuroscience field is to understand how connections and communications trigger our behavior.
Neurons that regenerate, neurons that die
In a new study published in Neuron, investigators report on a transcription factor that they have found that can help certain neurons regenerate, while simultaneously killing others.
How neurons use crowdsourcing to make decisions
When many individual neurons collect data, how do they reach a unanimous decision?
Neurons can learn temporal patterns
Individual neurons can learn not only single responses to a particular signal, but also a series of reactions at precisely timed intervals.
A turbo engine for tracing neurons
Putting a turbo engine into an old car gives it an entirely new life -- suddenly it can go further, faster.
More Neurons News and Neurons 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.