Gender Brain Differences | Does it matter

   

Sex Differences in the Brain

Male and female brains differ in many ways.

 

·        Several parts of the male brain are larger than the female brain, similar, some part of the female brain has a larger portion,

 

·        Most brain areas show different reproductive behavior in both male and female.

 

·        The brain differences are not simply a result of the fact that men are larger. When researchers compare men and women who have the same overall brain volume, many of the patterns.

 

·        The cortical areas of males and females distinct on average in the hypothalamus, pituitary gland, parts of the spinal cord, and elsewhere. For example, parts of the female hypothalamus produce a cyclic pattern of hormone release, as in menstrual cycle, whereas the male hypothalamus releases hormones more steadily.

Sex Differences in the Brain

What causes all these differences?

 The mechanism is that within the hypothalamus, sex hormones act in different ways for different areas. Before birth and the first few days afterward, the blood contains high levels of alpha-fetoprotein (a protein produced in the liver of a developing baby) that binds to circulating estradiol and prevents it from entering cells. Therefore, the female brain is not exposed to estradiol instantly.

 

The male’s testosterone is in free form to enter the hypothalamus, where an enzyme converts it to estradiol, and the estradiol force to masculinizing effects instantly. That is, for early development, testosterone is a way of getting estradiol into the hypothalamus. (You’re right, that is confusing.)

The rate of action of estradiol differs in various parts of the hypothalamus. In the medial preoptic area, both testosterone itself and estradiol increase the production of a chemical called prostaglandin E2, which leads to an increase in microglia, dendritic spines, and synapses. That later develops male sexual behavior.

 In the part of the ventromedial hypothalamus, estradiol activates an enzyme called kinase that increases the release of glutamate. The ventromedial hypothalamus contributes to aggressive and sexual behavior as well as feeding. In the arcuate nucleus and the anteroventral periventricular nucleus, estradiol increases GABA production, which acts on astrocytes to decrease dendritic spines. The result for males is shrinkage of these areas that are important for female sexual behavior.

 These areas remain larger in females because of low levels of estradiol early in life.

 

The mechanisms include not only testosterone and estradiol but also a hundred genes that are also responsible for brain differences. Because some genes more active in one sex than others, and so do factors that cause epigenetic changes, the average brain structure does not apply to any individual. Very few people have a brain that is male-typical or female-typical in all regards. Instead, almost anyone’s brain is a mosaic of male-typical, female-typical, and approximately neutral areas.