Transsexual differences caught on brain scan
Antonio Guillamon's team at the National University of Distance Education in Madrid, Spain, think they have found a better way to spot a transsexual brain. In a study due to be published next month, the team ran MRI scans on the brains of 18 female-to-male transsexual people who'd had no treatment and compared them with those of 24 males and 19 females.
They found significant differences between male and female brains in four regions of white matter – and the female-to-male transsexual people had white matter in these regions that resembled a male brain (Journal of Psychiatric Research, DOI: 10.1016/j.jpsychires.2010.05.006). "It's the first time it has been shown that the brains of female-to-male transsexual people are masculinised," Guillamon says.
I like seeing such results appropriately framed with a sense of clarity about what they really tell us:
Guillamon isn't sure whether the four regions are at all associated with notions of gender, but Ivanka Savic-Berglund at the Karolinska Institute in Stockholm, Sweden, thinks they might be. One of the four regions – the superior longitudinal fascicle – is particularly interesting, she says. "It connects the parietal lobe [involved in sensory processing] and frontal lobe [involved in planning movement] and may have implications in body perception."
What an interesting bit of research - I hope that there's more like this to come.
2 comments:
Interesting. I'd like to see a much larger study group! And scans of female-to-male subjects as well.
Although, if it's a valid method... what about outing people? Or non-outed people throwing off the numbers?
(1) The article does talk about FTM subjects as well.
(2) The size of n in any study involving transsexuals has always been small; the studies cited in the article actually have pretty good sample sizes.
(3) Your question about 'outing' people (or non-outed people) and the effect on the numbers is a good one. That likely requires some very large population studies to get meaningful numbers. (and may only give us a baseline for the frequency of potential transsexual identity in society)
... since brain scans of this nature are fairly expensive, I'm guessing that won't happen for a long time yet.
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