The human brain’s often called “the 3-pound universe.” (Take hope! Albert Einstein’s brain weighed in at 2 pounds, 11 ounces.)
There are a hundred billion neurons (nerve cells), allowing for more connections among these busy, busy, busy transmitters than there are twinkling – or twinky – stars in the galaxy.
Line up these neurons (supposing just for a moment you have nothing better to do on a no-church Sunday and could perform a self-craniotomy), the resulting – mind you, mindless – line dance would be 621 miles long.
(I worked at Harper Hospital as an OR Tech following high school.
I witnessed a craniotomy, marveling how the patient’s brain contracted rhythmically to his heart beat. Gory details: four holes drilled in the skull, a flap sawed, folded back, revealing a blueish/white gelatinous – as in Jell-O! – brain.)
Poet Emily Dickinson, whose own graceful 19th century neurons danced to hymnal meters, wrote, “The brain is just the weight of God,/ For, lift them, pound by pound,/ And they will differ, if they do,/ As syllable from sound.”
Brains do differ. How much – say, between the statistically normal brain and that of a schizophrenic or bipolar person – a male and a female brain – a straight and gay brain – is being rapidly and tantalizingly mapped.
Last July the National Institute of Health launched its $3 million Human Connectome Project. The project combines a variety of MRI and CAT scanning and imaging technologies to systematically pinpoint wiring, micro-dot by micro-dot.
One outcome eagerly anticipated: how our inward galaxy of neurons give rise to a single conscious mind. (“The brain is wider than the sky,/ For, put them side by side,/ The one the other will include/ With ease, and you beside.”)
There’s growing evidence of differences between gay and straight brain structuring – some subtle, some pronounced, according to “The Male Brain,” by Louann Brizending, M.D. (Broadway Books, 2010; $24.99). She also wrote “The Female Brain.”
Her appendix (“The Male Brain and Sexual Orientation”) comments, “Are men gay because their brains are different? Studies have been conducted for two decades in order to answer this question. Some of them have found evidence of anatomical or functional differences between gay and straight brains. Others have established that genes play a part in determining gender orientation, which implies the existence of brain differences.”
(Get out your Grey’s Anatomy, Mary. It’s going to be a phrenological bumpy night!) Some recent findings are here abbreviated.
– A part of the hypothalamus called the supraciasmatic nucleus is twice as large in gay males as in straight males.
– A bundle of connections between the brain’s two hemispheres – called the anterior commisure – is also larger in gay males than in straight males. It’s also larger in straight females as well.
– The hypothalamus in gay male brains is stimulated by the scent of male sweat, but in the straight male brain it is not. “This suggests that a difference in the brain’s hypothalamic circuits for response to pheromones may attract gay males to the scent produced by the sweat glands of men and plays a role in their sexual orientation.” (And LA Fitness gym workout mania.)
– Spatial tasks: gay men perform more like straight women.
– Identical twin pairs are more likely to share sexual orientation than fraternal twin pairs. 35 percent of sexual orientation is attributable to genetic influences.
– The asymmetrical size of the two brain hemispheres that is characteristic of straight male brains is not observed in gay male brains. In this respect, gay male brains were more like female brains. Swedish research studies suggest that “there are differences between gay and straight male brains that are not directly involved in sexual attraction.”
Bridge, brunch, ballet anyone?