Healthy 70-year-olds would have as many neurons in a part of the brain linked to memory as adolescents, according to a new work published in the journal Cell, carried out by a group of North American researchers. The discussion is old among neuroscientists, who, for years, it has been suspected that the brain slowed the multiplication of neurons at very early ages.
Comprehending how the brain is changing throughout life is essential to open the roads to new treatments against diseases and conditions such as stress, depression, and amnesia but also to reformulate the theories in this regard.
“It seems that humans are different from mice, where [the production of neurons] decreases with age really fast and this could mean that we need these neurons for our complex learning abilities and the cognitive-behavioral responses to emotions,” explained Dr. Maura Boldrini referring to a study conducted in March which concluded that neurons production stops in childhood.
Large numbers of new neurons have been observed in the studied brains, regardless of age
In this case, the researchers studied the hippocampus of brains taken from autopsies of 28 people, both men and women, aged between 14 and 79. Unlike other similar studies, the team was able to study the whole hippocampus, instead of just parts of its as in other studies, which allowed the researchers to count the neurons in this area of the brain more precisely.
As reported, “although the number of neural stem cells was a little lower in people 70-year-old than in people in their 20s, older brains still present thousands of these cells. The number of new neurons in intermediate to advanced stages of development was the same for people of all ages.”
This does not mean that aging doesn’t cause important changes
Dr. Boldrini and her colleagues did find fewer proteins and fewer new arteries in the studied brains, which might suggest a disruption in the neuroplasticity in the brain (the capacity of the brain to make new links between brain cells).
Regarding the findings and the contrary evidence presented by other works, Jonas Frisén, a neuroscientist at the Karolinska Institute in Stockholm who did not participate in the new research explained that “the small differences in methodology, such as the way in which the brains were preserved or how the neurons were counted, they can have a great impact on the results, which could explain the contradictory findings.”