"We have found that the onset of puberty hits something like a 'switch' in the brain's frontal cortex that can reduce flexibility in some forms of learning," said study senior author Linda Wilbrecht, Associate Professor at University of California, Berkeley.
While gleaned from young female mice, the findings, published in the journal Current Biology, may have broad educational and health implications for girls, many of whom are entering the first stage of puberty as young as age 7 and 8.
"Puberty onset is occurring earlier and earlier in girls in modern urban settings – driven by such factors as stress and the obesity epidemic – and has been associated with worse outcomes in terms of school and mental health," Wilbrecht said.
The researchers discovered significant changes in neural communication in the frontal cortices of female mice after they were exposed to pubertal hormones.
The changes occurred in a region of the frontal brain that is associated with learning, attention and behavioral regulation.
"To our knowledge, this study is the first to demonstrate changes in cortical neurotransmission due to hormones at puberty," study lead author David Piekarski, a post-doctoral researcher in Wilbrecht's lab, said.
Overall, children have been found to have greater brain flexibility or "plasticity" than adults, enabling them to more easily master multiple languages and other elementary scholastic pursuits.
While they continue to learn after puberty, their cognitive focus in adolescence is often redirected to peer relationships and more social learning.
If hormonal changes start as early as second or third grade, when children are tasked with learning basic skills, a shift in brain function could be problematic, Wilbrecht said.
"We should be more thoughtful about aligning what we know about biology and education to accommodate the fact that many girls' brains are shifting to this adolescent phase earlier than expected," she said.