Visual cues inform the decision to cooperate

Eye contact and body language are essential in social interactions, but exactly how the brain uses this information to inform real-time behavior is not well understood.

By combining behavioral and wireless eye tracking and neural monitoring, a team of Rice University scientists and collaborators studied how pairs of freely moving macaques interacting in a naturalistic environment use visual cues to guide cooperative behavior complex and goal-oriented.

The study, published in Natureoffers the first evidence that the part of the brain that processes visual information – the visual cortex – plays an active role in social behavior by providing an executive area – the prefrontal cortex – with the signals needed to generate the decision to cooperate.

“We are the first to use telemetric devices to record neuronal activity from multiple cortical populations in the visual and prefrontal cortex as animals explore their environment and interact with each other,” said Valentin Dragoi, professor of electrical engineering. and computer science at Rice and the Rosemary and Daniel J. Harrison III Distinguished Presidential Chair in Neuroprosthetics at Houston Methodist. “When primates, including humans, interact, we make eye contact and use body language to indicate to our peers what we want to do.

“Until now, we didn’t know how what we observed guided our decision to cooperate or not, due to our inability to measure oculomotor events and correlate them with what neurons are doing at that moment. Because the technology did not exist, this knowledge was simply inaccessible.

Most of what neuroscience has learned about the neural underpinnings of cognition comes from studies in which animals were restrained and performed a task in isolation in response to artificial stimuli on a computer screen rather than during real interaction with their peers in a more naturalistic environment. The ability to track neuronal activity as animals move and behave freely represents a significant advance in neuroscience research and promises to shed new light on the inner workings of the brain.

“It’s been the golden dream of neuroscientists for a long time: to record neurons on the fly while the animal is moving freely,” said Dragoi, who is also scientific director of the Center for Neural Systems Restoration, an association in Houston. Methodist-Rice company dedicated to neuroscience research and therapeutic innovation. “We tracked populations of neurons in the visual cortex, the part of the brain that extracts information about vision, and in the prefrontal cortex, an executive area that encodes our decision to perform certain actions.”

During the experiment, two pairs of macaques were observed over several weeks as they learned to work together to obtain a food reward. On each trial, the monkeys moved freely in an enclosure separated by a clear partition. The monkeys had already learned that pressing a button would bring a tray of snacks within reach, but in testing this only happened if the animals pressed the button simultaneously. As the macaques’ cooperative skills improved, the frequency with which they responded to socially relevant cues—their partner, the snack tray—increased before acting in concert.

“This technology allows us to differentiate between active and passive vision,” Dragoi said. “Active vision is when we act on a stimulus that we observe with a goal in mind. When I am engaged in a social interaction, I act in some way, extracting visual information and using this information to cooperate. Our main discovery is to see how populations of sensory neurons extract information, transmit it to an executive area and how they synchronize in real time to underlie the decision to cooperate.

Behnaam Aazhang, JS Abercrombie Professor of Electrical and Computer Engineering at Rice, highlighted the critical contributions of Melissa Franch, the study’s lead author, a former Ph.D. student in Dragoi’s lab and now a postdoctoral researcher at Baylor College of Medicine, and Sudha Yellapantula, a former Rice doctoral student in Aazhang’s group who now works as a research professional in health care.

“They deserve a lot of credit,” said Aazhang, who is also director of the Rice Neuroengineering Initiative and co-director of the Center for Neural Systems Restoration.

“This work is highly interdisciplinary and involves a complex experimental design intended to test the hypothesis that the frontal visual cortex plays an important role in social behavior,” Aazhang added. “Many animals are not very social, but primates are, which was an important factor in the research, given the nature of the hypothesis.”

It turns out that expressions like “staring daggers” and “seeing into eyes” are more than just a quirk of the English language: we now have evidence that the visual cortex and the prefrontal cortex work in concert to obtain complex behaviors like cooperation.