NIH researchers discover new brain circuit for detecting faces

Press release

Tuesday July 2, 2020

Discoveries in non-human primates could shed light on how our brains develop facial recognition abilities.

Researchers Gongchen Yu Ph.D. Léor Katz Ph.D. and Richard Krauzlis Ph.D. discovered a circuit in the primate brain that quickly detects faces.Dustin Hays National Eye Institute

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Scientists at the National Institutes of Health have discovered a circuit that allows primates to quickly detect faces. These findings could help explain not only how primates detect and recognize faces, but also conditions like autism where the ability to recognize and identify faces is often affected from a young age. This circuit activates the superior colliculus of the brain, ancient during evolution, which then causes the movement of the head and eyes to see better. The better view allows different brain regions of the temporal cortex to perform more complex facial recognition. This study appeared in the Journal Neuron.

Richard Krauzlis Ph.D. of the National Eye Institute of the NIH and lead author of this study said: “Rapid face recognition is a key skill in humans and other primates. » This newly discovered circuit helps explain how humans can quickly recognize and focus on faces even when they appear in peripheral vision, where visual acuity may be low. The circuit may be the one that highlights faces and helps us learn to identify people. It could also help our brains understand facial expressions.

The brains of adult primates develop “face spots,” which are specialized areas of the temporal cortex that allow them to distinguish and recognize individuals based on their facial features. Facial recognition relies on the smallest details of central vision, which is of high acuity. To recognize a person, you have to look at them directly.

Face-specific cortical areas do not develop in babies until much later. Despite this, infants are able to look and orient toward faces from a very young age, suggesting that another mechanism is at work.

Scientists were left with a number of questions after these observations, such as: How does the brain move the eyes toward a particular face in order to see finer details? This facial preference is determined before the formation of brain “face spots”. How do “face spots” in the brain develop this ability to recognize faces?

Krauzlis and his colleagues hypothesized that the superior colliculus, known for its ability to detect objects, might provide the missing piece. It is part of the midbrain and tells other parts of the brain that something exists somewhere. Not what it is but just the fact that it's there. The midbrain is extremely fast and connected directly to the motor areas of the brain. It directs eye movements toward an object of interest or moves the body back in front of an object that appears in peripheral vision.

First authors Gongchen Yu and Leor KAT collected a variety of images including faces, faceless biological objects like arms and hands, and other objects like fruits or man-made objects. The researchers then presented these images in the peripheral vision field of adult monkeys and measured the neuronal responses.

Previous studies suggested that object detection by the superior coliculus was independent of the object. This means that the part of the brain simply notes the presence or absence of something without making a distinction as to what it might be. In this study, Krauzlis and colleagues found that more than 50 % neurons responded more strongly to faces in just 40 milliseconds, compared to other objects. Eventually, some additional neurons began to show preferences for different types of objects. However, this preference was only visible after 100 milliseconds. Face-specific detection, on the other hand, was faster and preferred by many neurons.

The researchers were also able to determine that although visual data can be received directly by the superior colliculus, the process of object detection first requires input from an early part of the visual cortex.

Scientists suspect that the circuit is used to emphasize the importance of specific objects, since the superior colliculus connects to the visual cortex at a later stage in the visual pathway.

Krauzlis said: “We think this facial preference circuit may underlie the brain's most sophisticated facial recognition functions. » If this is the case, then deficits in this facial preference within the superior colliculus could play a role in autism.

The NEI Intramural program funded this study. The research was also conducted by Christian Quaia Ph.D. and Adam Messinger Ph.D. in addition to Yu and Katz.

This release explains a result of fundamental research. Basic research helps us understand human behavior and the biology of disease. Each research advance builds on previous discoveries in unpredictable ways. Without basic research, most clinical advances would be impossible. Visit this site to learn more about the basics of research. https://www.nih.gov/news-events/basic-research-digital-media-kit.

NEI is the leading federal research agency in the field of diseases of the eye and visual system. NEI funds basic and clinical research programs that develop sight-saving treatments and meet the unique needs of people with visual impairments. Visit for more information. https://www.nei.nih.gov.

The National Institutes of Health: NIH is the medical research agency of the United States Department of Health and Human Services. It includes 27 institutes and centers. The NIH, the nation's medical research agency, is a component of the U.S. Department of Health and Human Services. It is responsible for conducting basic, translational, clinical and other medical research. Visit NIH for more information about its programs and services. www.nih.gov.

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