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Avraham threw himself on his face and laughed, he thought to himself, "Can a hundred-year-old child be born, or can Sarah have a child of ninety?" Genesis 17:17 (The Israel Bible ™)
Collage of multiethnic and diverse people expressing different emotions. (Credit: g-stockstudio / Shutterstock.com)
Despite intensive research, we can recognize the faces of friends and relatives we have not seen for years or celebrities we have never met. The way the brain realizes this has remained a mystery.
Our world would be very different – and much poorer and more confusing – if everyone had the same face. Thanks to our parents' genes, except identical siblings, everyone is different and their faces express essential information. Unfortunately, among the demented, the ability to recognize the faces of people they have known for decades is very much in jeopardy.
Most of us can recognize the face of a famous person even if it appears only a fraction of a second or the face of an old friend in college, even after decades without seeing it. Many of us can feel the mood of another important man who comes from facial expression. Often, we can determine if a person is trustworthy just by looking at his face.
A study has just been published in Neurology, The medical journal of the American Academy of Neurology identifies for the first time the neurons of the human visual cortex that respond selectively to faces. The study was carried out by Dr Vadim Axelrod, head of the Laboratory of Consciousness and Cognition at the Center for Multidisciplinary Brain Research at Bar-Ilan University, Gonda (Goldschmied), in collaboration with a team from the Brain and Spinal Cord Institute and the Hospital Pitié-Salpêtrière directed by Prof. Lionel Naccache.
Researchers have shown that neurons in the visual cortex (near the surface of the fusiform surface) respond much more strongly to faces than to landscapes or objects in a city. The response of the brain was much more energetic when she saw famous actors or politicians than when we looked at the Louvre in Paris, the Taj Mahal in Agra, India, a chisel or a backpack or, in this case , unknown faces of the participant in the experiment. In an additional experiment, the neurons showed a selectivity of faces vis-à-vis human and animal faces appearing in a film (excerpt from Charlie Chaplin). The circus).
"In the early 1970s, Professor Charles Gross and his colleagues discovered the neurons contained in the visual cortex of face-reacting macaque monkeys. In humans, selective facial activity has been extensively researched, mainly using non-invasive tools such as functional magnetic resonance imaging (fMRI) and electroencephalograms, "said lead author of the document, Axelrod.
"Strikingly, the neurons of the face in the posterior temporal visual cortex have never been previously identified in humans. In our study, we had a very rare opportunity to record neuronal activity in a single patient while micro-electrodes were implanted near the spindle-shaped area – the largest and most likely region. the most important of the human brain.
The best-known neurons that respond to faces are the "Jennifer Aniston Cells", medial temporal lobe neurons that respond to different images of a specific person (for example, Jennifer Aniston in the original study published in Nature Quiroga and his colleagues in 2005). "But the neurons of the visual cortex that we have reported here are very different from the neurons of the medial temporal lobe," says Axelrod. "First, the neurons of the visual cortex respond vigorously to any type of face, regardless of the person's identity. Second, they respond much earlier. Specifically, while in our case, a strong response could be observed in the 150 milliseconds that followed the display of the image, the "Jennifer Aniston cells" typically took 300 milliseconds or more to respond. "
The present results provide unique insights into the functioning of the human brain at the cellular level during facial treatment. These discoveries also help to better understand facial mechanisms among species (such as between monkeys and humans). "It's really exciting," concluded researcher Bar-Ilan, "that after almost half a century since the discovery of facial neurons in macaque monkeys, it is now possible to demonstrate neurons similar in humans. "
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