Sunday, April 26, 2015

Uncertain Health in an Insecure World - 36

"That Other Sex Organ"

Let’s look at that other sex organ… The Brain.

Because only men have the Y-chromosome, and because that Y-chromosome is present in every male brain cell on Earth, it could be fairly stated that the male brain differs from the female brain.

In fact, the 50-60 sex-specific genes that uniquely exist on the Y-chromosome add genetic proof to the concept that men’s brains are different from women’s.

Sex bases for and biases causing health gender disparities are both obvious, and controversial.

Obviously, Y-chromosomal genes don’t make men’s brains better… just different from those of women. The proteins and neurotransmitters coded for by these brain genes may contribute to different neurocognitive genetic traits between females and males, such as recognized gender advantages in languages & memory for women and spatial discrimination for men.

While controversial, many environmentalists, epi-geneticists and neuroscientists believe that in utero toxin exposure and birth prematurity stress accentuates future neurocognitive deficits, also possibly contributing to disease differences between the sexes.

A 2013 PNAS report described the mapping of neural circuit connectivity in the brain scans of nearly one thousand 8-22 year olds. These so-called connectomes have produced insights into brain wiring that may explain gender-based neurocognitive and developmental differences. Boys and girls had similar connectomes up to age 13, with differences appearing between ages 14-17. While right-left hemisphere connections were more developed in young women (above), the right-left connections in the balance center cerebellum were more developed in young men. In general, frontal-occipital connections were also better developed in male brains (below).

Such wiring differences could partially account for gender differences in the biological susceptibility to and age-of-onset of chronic disorders like schizophrenia and depression.

Since 2002, the World Health Organization (WHO) has recognized and actively addressed the obvious health vulnerabilities of women around the globe, with a clear emphasis on socio-economic-cultural disadvantages and the adverse aftermaths of forced migrations & natural disasters.

Highly adverse life circumstances can overwhelm sex-based genetically predisposed brain biology.

Low maternal socio-economic status (SES) and childhood poverty, which affects 47 million children worldwide according to the Organisation for Economic Cooperation & Development (OECD), adversely impacts brain structure & functional organization and early cognitive development.

The culturally-imposed practice of circumcision affecting 125 million women & girls living in 29 African, Middle Eastern and Indonesian countries (and per NHS, 66,000 UK residents!) is called female genital mutilation (FGM). The WHO has considered this as extreme gender discrimination and a violation of the human rights since 2008. Resulting reproductive problems and psychological disorders can be debilitating and long-lasting.

Ironically, the WHO Health 2020 campaign in Europe has decidedly not focused on studying controversial sex-specific health differences.

Why is that?

Perhaps because the daunting realities of developing policies and financing practices to address the root causes of such globally pervasive gender-based health disparities & crises makes securing airplane cockpits from male pilots with suicide on their minds or from male passengers with terrorism in their brains seem simple and cheap by comparison.

One final piece of the sex-brain puzzle remains for our future consideration. 

Scholars at the University of California report REM deep sleep changes in genital blood flow during erotic dreams. Scientists from the Universite de Montreal report that 8% of our dreams are erotic, and that 4% result in spontaneous orgasms. While the biology of a brain-triggered orgasm is interesting, the teleology of reported differences in the experience between men and women is fascinating.

  The newest Diagnostic and Statistical Manual of Mental Disorders (DSM-5, 2013) includes a medical disorder of women who experience repeated hands-free orgasms known as persistent genital arousal disorder (PGAD). Ironically, this uncontrollable female genital arousal can be unpleasurable, and may rarely lead to depression and suicidal behavior. Not to be left out, a male case of PGAD causing 100 orgasms per day was reported in 2014.

Calling this a disorder in women smacks of sexism, either way you might choose to take it.

But the fact is that our sex genes control our brains, and our brains control our behaviors. When our insecure world affects brain wiring, or when abusive cultural beliefs make women's health uncertain, the relationship of gender to sex... of biology to behavior... becomes blurred.

We in the Square admit that it's sexier to sequence a Y-chromosome in a lab and to dangle the allure of precision medicine than it is to address complex gender-based health disparities in the real world.

Mea culpa... It hurts our brains.

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