A new study by researchers at Uppsala University has found that prenatal sex-based biological differences can extend to genetic expression in cerebral cortices and are probably associated with later divergences in how our brains develop.
Elena Jazin and Bjorn Reinius had earlier showed that genetic expression in the cerebral cortices of human beings and other primates exhibits certain sex-based differences.
It is presumed that these differences are very old and have survived the evolutionary process.
The new study was aimed at finding whether they appear during the process of brain development or first upon the conclusion of that process.
Identifying the initial genetic mechanisms that prompt the brain to develop in a female or male direction is a long-range research objective.
The researchers analysed data, on the basis of sex, from another extensive study of the prenatal human brain.
"The results show that many of the genes situated on the Y chromosome are expressed in various parts of the brain prior to birth and probably provide a developmental basis for the sex-based differences exhibited by adult brains," said Jazin.
t is still unknown whether the differences in genetic expression among female and male brains have any functional significance.
"The findings are consistent with other factors, such as environment, also playing a role in how we develop," emphasized Jazin.
Knowledge of the development of sex-based brain differences is of potential significance for the treatment of brain disturbances and diseases.
A large number of psychiatric illnesses, including depression and autism, affect men and women differentially.
"Taking account of sex-based differences is crucial to the study of normal and abnormal brain activity," said Jazin.
The study has been published in the latest issue of the journal Molecular Psychiatry.