Published on 05/04/2022 at 10:08 a.m.,
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Socializing is good for your brain! This recommendation often made to repel the risk of dementia is now confirmed by a Franco-American study conducted on primates.
For several years, the links between social interactions and brain size have been the subject of numerous studies. Recently, researchers from Inserm and the University of Lyon Claude Bernard Lyon 1, in collaboration with the University of Pennsylvania, took an additional step to better understand this link. They were particularly interested in a species of primates whose brain architecture is comparable to that of humans: rhesus macaques.
Evolving in a “social environment” contributes to the maturation of brain networks
In an attempt to understand the development of the human brain, scientists observed a group of rhesus macaques in their natural environment for several months.
The grooming sessions – which represent privileged moments of social interaction for the monkeys – have in particular been closely scrutinized. A total of 103 individuals were observed, including 68 adults and 21 young macaques under 6 years old.
In parallel with this observation work, the researchers analyzed images of their brains. They found that the number of primate mates predicted the size of certain brain areas involved in social decision-making and empathy.
“The more the animal had a large number of companions, the more certain regions of its brain located in the temporal lobe were of significant size.can we read in the study.
More specifically, it would be the anterior insula and the median part of the Superior Temporal Sulcus – crucial regions at the emotional and behavioral level.
Brain size increases with age
In addition to these initial results, 21 brains of young newborn macaques were scanned.
The results showed that the young monkeys were not born with differently sized brain structures, but that these were put in place as they evolved.
Clearly, there would therefore be no link between the size of the social network and the volume of the brain at birth. It is by evolving in a social environment that the brain “mature”.
“This aspect is interesting, because if we had observed the same correlation in young macaques, it could have meant that being born from a very popular mother (having a lot of interaction with the group), could have predisposed the newborn to become in turn popular. On the contrary, our data suggest that the differences we observe in adults are strongly determined by our social environments, perhaps more than our innate predisposition.”explains Jérôme Sallet, research director at Inserm.
Scientists now want to analyze cellular changes to reveal how brain volume increases.