Puberty Different boys and girls

Different cerebral blood flow during puberty

27/05/2014

The gender is often attributed to different characteristics: Men are less sensitive or women socialized. A study may now have found an explanation for such differences. The researchers found that the cerebral blood flow of boys and girls develops differently during puberty.

Cerebral circulation in women more than in men
The brains of girls and boys develop in opposite directions during puberty. From this time, the female brain is better supplied with blood than the male. Researchers led by Theodore Satterthwaite of the University of Pennsylvania, Philadelphia, found particularly marked differences between the sexes in certain brain regions. As in the trade magazine „Proceedings of the National Academy of Sciences“ („PNAS“), the differences could be related to susceptibility to mental illness. The team of scientists writes: „Circulation is a fundamental feature of brain processes, and it is known to be more severe in women than in men in adulthood.“

Circulation of the brain decreases during childhood
In order to find out how the differences come about, the researchers measured 922 adolescents aged 8 to 22 years of age at different stages of puberty with magnetic resonance imaging (MRI) and other imaging techniques. They came to the conclusion that cerebral blood flow in early puberty, ie at the age of about twelve years, still declined equally among girls and boys. It had previously been known that the blood flow to the brain decreases during childhood. While in children more than 100 milliliters of blood flow through 100 grams of brain per minute, this amount tends to be only half as high in adults.

Differences between the sexes from the middle phase of puberty
But from the middle phase of puberty, ie at the age of about 16 years, the scientists found differences between the sexes. Thus, the blood flow continued to decrease in boys, whereas in girls it increased slightly. This trend even intensified in later puberty. As the researchers reported, the differences were most pronounced in brain regions such as the orbitofrontal cortex, which are associated with social behavior and the regulation of emotions: „We suspect that gender-specific changes in cerebral blood flow associated with puberty may be related to women's superiority in these tasks.“

Findings could help in researching mental illnesses
The team around Satterthwaite writes that the findings could help research into mental illnesses such as depression that often occur after puberty. Therefore, future studies should examine whether better cerebral blood flow in young women is related to their increased risk of suffering from affect or anxiety disorders. It could also reduce the risk of schizophrenia. It could also be a first step in creating growth charts for normal brain development, says the scientist. You may be able to spot problems before they lead to serious illnesses.

Mystery of mental instability during puberty
Psychiatrist Satterthwaite stated: „Our results show when the differences begin in the brain, and perhaps we can deduce which developmental stages are typical at which age.“ But even if the new findings as well as those from other investigations stir up hope, it still remains an illusion that with images of the brain the mystery of mental instability during puberty could be fathomed. Although mood swings in adolescents have often been attributed to an increased level of hormones, it is now known that this relationship exists but is not as strong as previously thought. Rather, this is due to a combination of hormonal and situational factors. The shape and structure of the brain, with the exception of newly observed differences, show little difference between the sexes. As the „Southgerman newspaper“ (SZ) writes, said Jay Giedd of the National Health Institutes of the United States: „One can not even distinguish the brain of a girl from that of a boy in these pictures.“ (Sb)