Cerebral Blood Flow Changes Accentuate Puberty Differences

The confusing time of adolescence is also defined by a change in blood flow, according to a recent study from researchers at Penn Medicine. They found that cerebral blood flow (CBF) levels decreased similarly in males and females before puberty. However, following, sharp changes marked each gender. For females following puberty, levels were known to increase, while they decreased in males. This may be the reason for certain behavioral differences in both genders, along with sex-specific pre-dispositions to certain psychiatric disorders.

"These findings help us understand normal neurodevelopment and could be a step towards creating normal 'growth charts' for brain development in kids. These results also show what every parent knows: boys and girls grow differently. This applies to the brain as well," said Theodore D. Satterthwaite, MD, MA, assistant professor in the Department of Psychiatry in the Perelman School of Medicine at the University of Pennsylvania, via a press release. "Hopefully, one day such growth charts might allow us to identify abnormal brain development much earlier before it leads to major mental illness."

As previous studies have shown the importance of puberty in gender differences, research has also shown how CBF declines throughout childhood but can have significant effects on certain properties of the brain's physiology. "We know that adult women have higher blood flow than men, but it was not clear when that difference began, so we hypothesized that the gap between women and men would begin in adolescence and coincide with puberty," Satterthwaite added, via the release.

For the study, researchers imaged the brains of 922 youths aged 8 through 22 using arterial spin labeled (ASL) MRI. All participants were members of the Philadelphia Neurodevelopmental Cohort, a National Institute of Mental Health-funded collaboration between the University of Pennsylvania Brain Behavior Laboratory and the Center for Applied Genomics at the Children's Hospital of Philadelphia.

Researchers discovered that the amount and location of blood flow in males versus females began to change around the age of 16. Females showed signs of notably higher CBF levels while males had lower levels. Such differences may be due to an increased risk of certain anxiety disorders in women or females' ability to perform better on social cognition tasks than males. Other research also suggests that such levels may be determined by increased risk of flat affect and schizophrenia in men.

More information regarding the findings can be seen via the Proceedings of the National Academy of Science (PNAS).