March 5, 2013
New Brain Cells Added During Puberty
redOrbit Staff & Wire Reports - Your Universe Online
Two US neuroscientists have discovered new cells are added to a person´s brain when they go through puberty — a biological change designed to better equip growing boys and girls for the rigors of becoming adults.Previously, experts had believed the human brain maintained a set number of cells from birth through old age, but then studies demonstrated that new brain cells were formed in adults. Initially, it was believed those new cells were limited to specific areas of the brain — regions associated with memory and smell — but recently scientists at the Michigan State University neuroscience program have shown otherwise.
Researchers at the East Lansing-based university have demonstrated that the brains of mammals also add new cells to the amygdala, which helps recognize and respond to social cues, and interconnected regions during puberty.
In humans, it helps evaluate the facial expressions and body language of those we interact with. In hamsters, it helps pick up signals transmitted through pheromones (excreted chemicals intended to trigger some type of social response among other members of the same species).
"These regions are important for social behaviors, particularly mating behavior," doctoral student Maggie Mohr, who teamed up with MSU psychology professor Cheryl L. Sisk to study this phenomenon on the burrowing rodents, said Monday in a statement.
“So, we thought maybe cells that are added to those parts of the brain during puberty could be important for adult reproductive function,” she added. “Before this study it was unclear if cells born during puberty even survived into adulthood. We've shown that they can mature to become part of the brain circuitry that underlies adult behavior.”
Mohr and Sisk injected male hamsters with a chemical marker to help them detect cell birth during puberty. As the hamsters matured into adulthood, they were allowed to approach and even mate with females. Mohr and Sisk then examined their brains immediately afterwards.
They discovered new cells born during puberty had been added to the amygdala and other nearby regions. Among those new cells was a protein that indicated cell activation, indicating to the researchers those cells had been ingrained into the parts of the brain responsible for social and sexual behavior. They report their findings in the latest edition of the journal Proceedings of the National Academy of Sciences.
"We don't know if cells are added to the human amygdala during puberty," explained Sisk, "but we know the amygdala plays a similar role in people as in hamsters. We hope to learn whether similar mechanisms are at play as people's brains undergo the metamorphosis that occurs during puberty."