Brain, neurons that help us remember faces discovered

Identified in the temporal pole of the brain, the new class of neurons connects the area of ​​immediate visual perception with that of long-term memory

How do we do a recognize faces immediately who are familiar and known to us? THE neuroscienziati they have been wondering for some time and the hypotheses are various. Today a research group from Rockefeller University identified one new class of neurons in a region of brain call time pole (highlighted in the image below), which connects the area where the perception immediate of a total with that of memory long-term. This is the first proof, according to the authors, of how the faces of our loved ones are fixed in a lasting way in our memories. The results, still to be investigated and limited because obtained on two specimens of macaques, could open new avenues of research also against the prosopagnosia, a disorder consisting in the inability to recognize familiar faces. The study is published on Science.

(photo: Sofia Landi)

“Grandma’s neuron”

It is difficult to forget a face, especially if it is a person we have met more than once: the memory of his features will remain with us for a long time and will allow us, in the next meeting, to recognize him immediately, without delay. Scientists have long been trying to understand why this is how this happens and in what way, if there is a joining link from le visual brain areas to those of memory. So far an advanced theory in the 60s of the last century to explain the storage of memories is linked to the “grandmother’s neuron “, a hypothetical neurone which acts as a connection and point of union between sensory perception and memory and which would help to remember the face of a person. The idea is that for each face there is a neuron dedicated and in charge of this task. If over time many neurons specialized in the processing of visual information related to faces and others associated with memories have been identified, this connecting neuron however has not yet been identified.

Studying facial recognition

After the recent discovery, by the group of Winrich Freiwald by Rockefeller, also author of today’s work, of an area of ​​the brain, in time pole, involved in facial recognition, the researchers focused their attention on this area to look for new clues on the subject. To study it they carried out functional magnetic resonance tests on two macachi (of the rhesus macaque species) and recorded electrical signals from neurons in that region as the animals watched familiar and unknown faces on a screen.

A new class of neurons

Neuroscientists found that the temporal pole neurons were highly selective e they recognized familiar faces very quickly, distinguishing them from unknown ones. The response and activation, in the case of familiar features, was three times higher, even if the unknown faces had passed on the screen several times and therefore had repeatedly received the attention of the animal. This finding provides more than a clue, according to the researchers. Meanwhile, in their opinion it suggests the presence of one new class of neurons, hybrids, not so different from the grandmother’s neuron – even if in that theory a neuron corresponded to a memory, in a 1: 1 ratio, while here we are talking about a set of cells – and responsible for the connection between perception and memory.

For the memory, better live than online

Furthermore, the fact that the faces repeatedly proposed on the screen were not recognized could mean, as Sofia Landi, first author of the publication, points out that the recognition facial, learning of a face and the Consolidation in memory they might be different when the whole process takes place on a screen, virtually. “This could highlight theimportance of getting to know each other live“, Comments Landi, who remembers how more and more often – also due to force majeure, such as the pandemic – we tend to know each other online, but that the activation of neurons it may not be the same as what occurs when face to face. The study provides initial evidence, yet to be confirmed, but lays the foundation for a targeted study of this part of the brain. New findings could help in the future to better understand the mechanisms behind the prosopagnosia, the face blindness, and to hypothesize new interventions.

Categories:   Science