Though cerebral blood flow levels decrease in the same way for both boys and girls before puberty, new research reveals that they differ significantly during puberty; levels increase in females and decrease in males. Researchers say their findings give clues to sex-specific susceptibilities to certain psychiatric disorders, such as depression, anxiety and schizophrenia.
The researchers, led by Dr. Theodore Satterthwaite of the Perelman School of Medicine at the University of Pennsylvania, publish their research in the Proceedings of the National Academy of Science (PNAS).
They explain that puberty is the time during adolescent development when a multitude of changes occur in the body and brain, and other studies have shown that this period of development produces several sex differences.
While previous studies have shown that cerebral blood flow (CBF) declines during childhood, the effects of puberty on brain physiology - including CBF - are not well studied.
"We know that adult women have higher blood flow than men," says Dr. Satterthwaite, "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."
To further investigate, he and his team used arterial spin labeled MRI to image the brains of over 900 young people between the ages of 8 and 22 years old.
Findings link to higher anxiety risk in women, schizophrenia risk in men
CBF differs between boys and girls during puberty, suggesting sex-specific predispositions to certain psychiatric disorders.
The participants were all part of the Philadelphia Neurodevelopmental Cohort, which is a collaboration - funded by the National Institute of Mental Health - between the University of Pennsylvania Brain Behavior Laboratory and the Center for Applied Genomics at the Children's Hospital of Philadelphia.
The team observed age-related differences in both amount and location of blood flow in the males and females.
At age 16, male CBF continued to decline, while female CBF values increased.
By the end of adolescence, females had significantly higher CBF than males, and this difference was most prominent in areas of the brain involved in social behaviors and emotion regulation, such as the orbitofrontal cortex.
Commenting on their results, Dr. Satterthwaite says:
"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."
He says he and his team hope that "one day, such growth charts might allow us to identify abnormal brain development much earlier before it leads to major mental illness."
The researchers theorize that such differences between males and females could be linked to why females consistently perform better on social cognition tasks.
They add that these findings could link back to the higher risk for depression and anxiety disorders in women, and the higher risk of schizophrenia in men.
Medical News Today recently reported on a stem cell study that suggested schizophrenia begins in the womb, after showing that neurons from skin cells of patients with schizophrenia behave oddly in early stages of development.
Meanwhile, another study identified a genetic overlap between schizophrenia and autism.