Study finds how our brain recognises familiar faces


Different information about familiar faces is encoded in a neural code that is shared across the brain, according to a new study.

New Delhi: Different information about familiar faces is encoded in a neural code that is shared across the brain, according to a new study.

The study findings were published in the journal Proceedings of the National Academy of Sciences. The ability to recognize familiar faces is fundamental to social interaction. This process provides visual information and activates social and personal knowledge about the familiar person.

But how the brain processes this information among participants has long been a question.

“Within visual processing regions, we found that information about personally familiar and visually familiar faces is shared in the brains of people who have similar friends and acquaintances,” said first author Matteo Visconti di Olegio Castello, Guarini ’18. who did this research. as a graduate student in psychological and brain sciences at Dartmouth and is now a neuroscience post-doctoral scholar at the University of California, Berkeley.

“The surprising part of our findings was that shared information about personally familiar faces extends to regions that are important for non-visual and social processing, suggesting that there is shared social information in the brain.” Castello said.

For the study, the research team applied a method called hyperalignment, which creates a common representation space to understand how brain activity is similar between participants. The team used data from three fMRI tasks with 14 undergraduate students who had known each other for at least two years. In two tasks, participants were presented with images of four other personally familiar graduate students and four other visually familiar individuals, previously unknown.

In the third task, participants viewed parts of ‘The Grand Budapest Hotel’. The movie data, which is publicly available, was used to implement hyperalignment and to align participants’ brain responses into a common representation space. This allowed the researchers to use machine learning classifiers to predict what stimuli a participant was seeing based on the brain activity of other participants.

The results showed that visually familiar and personally familiar faces were identified with accuracy throughout the brain in regions that are mostly involved in the visual processing of faces. Outside of visual fields, however, there wasn’t much decoding. For visually familiar recognition, participants knew only what the stimulus looked like; They did not know who these people were or any other information about them.

In decoding personally familiar identities, the findings demonstrated that there was a great deal of shared information in the participants’ brains. Four other regions outside the visual system had higher decoding accuracy: the dorsolateral prefrontal cortex, which is known to be involved in social processing (processing other people’s intentions and symptoms); The precuneus, a region that has been shown to be more active when processing familiar faces individually; the insula, which is known to be involved in emotional processing; and the temporal-parietal junction, which plays an important role in social cognition and in representing the mental states of others (also known as “theory of mind”).

Senior author Maria (Ida) Gobini, a research associate professor in the Cognitive Science Program at Dartmouth and associate professor in the department, said, “This shared conceptual space for the personal knowledge of others allows us to communicate with people we don’t know in common. know as it is.” of Experimental, Clinical and Specialty Medicine at the University of Bologna.

Previous research by the team using fMRI experiments found that these “principles of mind” regions in the brain are activated when a person looks at a personally familiar person.

Gobini said, “When we see someone we know, we are immediately activated as to who that person is. This is what allows us to interact with an acquaintance in the most appropriate way. Is.” For example, how you interact with a friend or family member may be quite different from how you interact with a co-worker or boss.

“It would have been quite possible that everyone had their own personal code of what people like, but that’s not the case,” said co-author James Haxby, a professor of psychological and brain science at Dartmouth.

“Our research shows that processing familiar faces actually has to do with common sense about people,” Haxby concluded. (ANI)

First published:November 2, 2021, 4:43 PM

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