More on the BST-c brain area associated with transexualism

[Krististeph]

I was reading over this subject again, looking at a number of papers (item quoted below in blue is just a general reference to the subject), and notice that the stated parameters always speak of (male) transexualism (TS) with some subgroups as early or later onset, and attracted to (either) men or women.

It seems to me that crossdressing, although often linked with transexualism, it is significantly different. Of the subgroups mentioned, the TS with female orientation seems to fit best, but is not the most accurate description of a significant proportion of the CD/TG/TS.

Now, since we are all conceived as and initially develop as females, somehow the hormones in the fetus beginning at about 8 weeks are not as complete, thus failing to masculinize ( androgenize(?) ) the BSTc region, but most everything else.

I wonder if the BST-c is different for crossdressers rather than transsexuals, as sort of an incomplete or half-way?






A possible explanation, but least likely: The Zhou/Kruijver results might reflect the chance selection of a sample of MtF transsexual brains with unrepresentative BSTc volumes and neuron numbers
Examination of the Zhou/Kruijver data reveals considerable variability in BSTc volume and neuron number within each of the groups they studied (i.e., MtF transsexuals, heterosexual men, homosexual men, and women). Could it be that there is really no difference in average BSTc volume and neuron number between nontranssexual men and MtF transsexuals and that the differences found in the Zhou/Kruijver studies merely reflected the chance selection of a highly unrepresentative group of MtF transsexuals?
Statistical testing provides an estimate of the likelihood of such an occurrence. In the case of BSTc volume, the observed difference in mean values between the MtF transsexual group and the heterosexual male group would be expected to occur by chance less than one time in 200 (p < .005; Zhou et al., 1995, p. 69). In the case of BSTc neuron number, the probability is greater, but still less than one time in 25 (p < .04; Kruijver et al., 2000, p. 2036). <<http://www.annelawrence.com/twr/brain-sex_critique.html>>

[kimdl93]

This is certainly suggestive of a relationship between BSTc volume and to a lesser degree neuron number. Perhaps there are gradients in both that may be expressed by diffences of degree between CD and TG or TS individuals.

In performing this study, I would imagine that they focused on TS because as a group TS individuals are homogeneous that the TG or CD populations, since individuals identifying themselves as TG or CD may be more ambiguous about their need/interest to express femininity.

[LilSissyStevie]

You might be interested in this blog post in order to get some perspective on what it means.

http://sugarandslugs.wordpress.com/2011/02/13/sex-differences/

[Persephone]

Fascinating, Krististeph!

Could you post references to some of the papers?


You might be interested in this blog post in order to get some perspective on what it means.

http://sugarandslugs.wordpress.com/2011/02/13/sex-differences/

A great reference, thanks!

Hugs,
Persephone.

[Kate Simmons]

Well, we are each a unique individual and have our own specialty Hon. In the final analysis, we are exactly who we are supposed to be. Most who really know themselves will realize this, physiology notwithstanding.:)

[LisaMallon]

Oh it is definitely something different in the brain (duh).

Still very early days yet in research and we have nothing like any complete answers. But we might (just might) be getting some clues.

Anne Lawrence just gets confused about the positive/negative feedback mechanisms that can moderate, accentuate or channel an innate desire. She confuses feedbacks as causes.

She is wrong, sadly that mistake, in all areas of human behaviour, is quite common.

You now how I analyse this: the drive is innate, the expression is a function of how all those feedback (external and internal) mechanisms channel that drive.

Now no one is 'just' a CD (as one thread here put it) for example, especially if you are long term and quite committed to it. Just you have found a balance that suites you to deal with that part of the brain that keeps telling you that your are a female. I find this whole CD/TG/TS argument thing amusing at times and a bit sad at others.

There really is no difference, except in degree. And some of that degree is a pretty fuzzy.

Take the great (and wonderful) Karren, she has done more body modifications than I have .. and I am a TS.

So I see it all as a sister/cousin thing. The brains are similar, the expression varies.

[noeleena]

Hi,

I would like to point out that from concepstion no we are not ,= initially develop as female, as has been said for many years its compleatly flawed, that would then mean the fetus would have female hormones flowing around the body. that then could be the case to say male hormones are doing the same thing its not so.

the ? should be raised then as to when is the fetus programed for the hormones to start. at conception no... or later then the body will be programed to start hormons hormones are only a miner part any way. ether male or female or both. or any number of differences. a lot more has to happen first before theres any show of any difference between boy or girl thats only body wise.

now the mind is totaly a different detail all to gether, & how the brain is wired & any thing can happen there. I can attest to that as being intersexed,.& how the brain develops & the changes that take place there,.


The 2nd problem is us who are intersexed, the same applys are we then male or female as in just after conception we are nether. more info is comeing to light now so we,ll have more on that,

...noeleena...

[Krististeph]

Hi,

I would like to point out that from concepstion no we are not ,= initially develop as female, as has been said for many years its compleatly flawed, that would then mean the fetus would have female hormones flowing around the body. that then could be the case to say male hormones are doing the same thing its not so.

...noeleena...

I would not go so far as to say its completely flawed, but i'll concede it's a rather oversimplified view. The crux of the mechanism is (in males) the production of androgens at about 8 weeks which interfere with the organs and systems developed by estrogen like compounds. But i'm out of my depth to argue it properly.

[Krististeph]

Fascinating, Krististeph!

Could you post references to some of the papers?
A great reference, thanks!

Hugs,
Persephone.

I'm just googleing here- try versions of "BST-c brain area" for more...

http://www.genderpsychology.org/psychology/BSTc.html

http://en.wikipedia.org/wiki/Stria_terminalis

http://www.annelawrence.com/twr/brain-sex_critique.html

http://transhumanoid.wordpress.com/2012/01/28/brain-sex-transsexual-bstc/

Also look at the references in the above articles and the articles you find on your own- there is some info out there, but a lot of it seems to come from a limited source pool.

As Samual Clemens said: "There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact."

Kristi

[Foxglove]

As Samual Clemens said: "There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact."
Kristi

Yes, and it's also easy to see that some scientists have their biases before they even start studying a question, as is obvious from some of the links you've given above. Scientists are as human as the rest of us, and they can often have trouble setting aside their biases and being objective. Nonetheless, we do learn, and we do make progress in science.

Very interesting thread, Kristi. Thanks for posting. You gave me a good evening's read, and I learned a few things.

[Marleena]

Can't some scientist just give us the real reason to why?:D

Instead of cloning cows and stuff why not find out why we are the way we are?

[Foxglove]

Instead of cloning cows and stuff why not find out why we are the way we are?

Marleena, I don't think we're very high on many people's list of priorities. I know, it's a bit insulting that they find cows more interesting than us, but at least it tells us that they don't regard us as cows.

Annabelle

[Marleena]

Marleena, I don't think we're very high on many people's list of priorities. I know, it's a bit insulting that they find cows more interesting than us, but at least it tells us that they don't regard us as cows.

Annabelle

Lol..yeah that is insulting now that you mention it!:) It would be great for parents with young transgender kids to know it's not just a phase the child is going through. There would be less messed up adults later on trying to figure this crap out.

[Foxglove]

It would be great for parents with young transgender kids to know it's not just a phase the child is going through. There would be less messed up adults later on trying to figure this crap out.

You're absolutely right. One thing I've been noticing lately is articles that are more or less scientific and are downplaying the differences that are beginning to be found in the TS brain. I myself would say that as yet I've read nothing that I find absolutely convincing about the differences between our brains and those others. So I have no quarrel with those who say that we need more evidence. What I'm noticing, though, is a resistance to the notion that there might be any difference at all. That is, certain parties are trying to deny that any differences could possibly be found. And I ask, how can anybody say that? It's early days yet. It seems to me that there are people who are saying this simply because they don't like TGism and they don't like the idea that TGism could be given a firm scientific grounding.

As you point out, it would be good for us if we could come up with conclusive evidence that such differences exist. So we do have a stake in the argument, and thus we have to be careful not to let our own biases come into play. It's early days. I'm in a wait-and-see mode myself. Unfortunately I seriously doubt that anything conclusive will be discovered in my lifetime. Maybe my son will some day have some explanation as to how I got so badly messed up.

Annabelle

[LeaP]

The general mechanisms for sexually dimorphic brain structures are WELL understood. What isn't confirmed to everyone's satisfaction is whether, or to what degree, these mechanisms are related to gender identity variance.

In the case of the brain, it's relatively straightforward. One either has sufficient aromatase to convert testosterone to estradiol to masculinize the brain, or one does not. (Female sex hormone is responsible for brain masculinization.) Since the genitals and the brain diverge in their sexual development at different times, and under different enzymatic mediation, the theory is that it's possible to masculinize the genitals yet (because of aromatase deficiency) leave the brain feminized.

Humans tend to complicate things. We LIKE to, of course, but the human consciousness is complex and so is our socialization. Animal studies manipulating brain sex, however, reliably produce cross-sexed behavior. It not too much of a leap to extend it to humans.

[Foxglove]

http://sugarandslugs.wordpress.com/2011/02/13/sex-differences/

This is exactly the type of article I'm suspicious of. The writer goes through a lot of stuff and makes it look very impressive in order to come to this conclusion:

For that reason, you can probably count on there never being a useful and reliable test for transsexualism based on sex differences.

What he's done is examine a couple of supposed differences between the sexes and shown that they're not actually good indicators as to a person's sex. The two indicators he analyzes are height and the "index finger-ring finger test". As for height, it's obvious from the beginning that it's not a reliable indicator of one's sex. Yes, on average men are taller than women, but heights vary a lot and there's considerable overlap between the sexes. The writer goes to great length and amasses a lot of statistical evidence to show us what we already know. As for the finger test, I don't know anyone who takes this seriously as an indicator of one's sex.

So the writer is basically trying to suggest that since these two indicators aren't reliable, it's unlikely that we'll be able to find any that are. He's saying that we're not likely to find indicators in the brain that will suggest that one might be TG.

But why use height and the finger test as one's criteria? Because, as becomes obvious from the last paragraph of this article, the writer isn't particularly sympathetic towards TG people. So he's interested in downplaying the notion that we might find "TG features" in the brain. Are there more reliable indicators of one's sex than height or the fingers? How about penis/vagina, testes/ovaries, heaviness of beard, breast size (in people of recommended weight), e.g.? In other words, we could find more reliable indicators, but the writer of this article has avoided mention of them in order to lead us to the conclusion he prefers. I find this whole article a "sand-in-the-eyes" type of argument.

Well, perhaps others of you can have a look at it and see if you agree with my critique of it.

Best wishes, Annabelle

[Josie M]

That is interesting, and the last paragraph was a "direct hit". I do have a finger ratio greater than one and I'd love to see results of a BSTc scan. I get the crux of the article though, it's not conclusive.

Still good article...

[MelanieB]

This is exactly the type of article I'm suspicious of. The writer goes through a lot of stuff and makes it look very impressive in order to come to this conclusion:

For that reason, you can probably count on there never being a useful and reliable test for transsexualism based on sex differences.


Annabelle

I agree with your suspicions over this type of Research

Having a slight scientific background myself, although, I hasten to add not in anyway related to this subject,
I think there has always been the possibility of researchers working within the confines of funding and time
limitations to get research papers printed and out in the scientific Journals despite the incomplete and inconclusive
nature of the work.

I'm not saying thats happened in this particular case (not wishing to face any defamation claims :heehee:) but it does leave
you somewhat sceptical about much of which is purported to be the "latest findings"

Just an opinion!!

[busker]

The last I knew, Anne Lawrence still chose autogynephilia - not brain sex - to explain TS. As far as I know, she's written only about the etiology of TS. The brain samples were from deceased TS. and they were 2 in number (as I remember reading, but could be mistaken). hardly enough to go one when making such a broad statement. Studies involving thousands of participants is what is needed. Too few samples are not reliable for any kind of hypotheses.

[ImAlexis]

I would not go so far as to say its completely flawed, but i'll concede it's a rather oversimplified view. The crux of the mechanism is (in males) the production of androgens at about 8 weeks which interfere with the organs and systems developed by estrogen like compounds. But i'm out of my depth to argue it properly.


It's the mullerian inhibiting substance that is the actual factor in inhibiting the development of internal female ductal reproductive organ (the uterus, fallopian tubesproximal 1/3 of the vagina). There was a study in rabbits (same one that showed that testosterone = male internal duct development) where the researchers removed the testicles from one side of male rabbits and the rabbits had male ducts on one side and female ducts on the other.

Androgens, especially 5-dihydroxytestosterone (5-DHT) is the most important for male external development and secondary sexual characteristics, but testosterone and weak androgens do contribute (hence androgen insensitivity disorder in genetic males and congenital adrenal hyperplasia in females).

Before someone asks, the gonads are set to female unless testicle determining factor is present. It's produced from the Y chromosome, but it can extremely rarely jump to the X.

[DianeDeBris]

Marleena, I don't think we're very high on many people's list of priorities. I know, it's a bit insulting that they find cows more interesting than us, but at least it tells us that they don't regard us as cows.

At least they haven't, yet, blamed us for global warming.

[ReineD]

I wonder if the BST-c is different for crossdressers rather than transsexuals, as sort of an incomplete or half-way?



In the case of the brain, it's relatively straightforward. One either has sufficient aromatase to convert testosterone to estradiol to masculinize the brain, or one does not. (Female sex hormone is responsible for brain masculinization.) Since the genitals and the brain diverge in their sexual development at different times, and under different enzymatic mediation, the theory is that it's possible to masculinize the genitals yet (because of aromatase deficiency) leave the brain feminized.

So if that's the case, then it's possible to have different levels of aromatase, which would account for varying degrees of feminine gender identification among birth males (CD vs. TS, plus a spectrum within each group)?

And how much do trade-offs between personality, background, and life circumstances with desires to express femininity come into play with decisions to pursue the CDing for CDers or transition for TSs? Also, how do the pleasure chemicals that are released early on, when for many people the expression of femininity or a feminine identity is sexual, play a part in rewiring the brain thus forming bonds that make the expression of femininity rewarding?

[Krististeph]

Can't some scientist just give us the real reason to why?:D

Instead of cloning cows and stuff why not find out why we are the way we are?

But just think of how cool an entire field full of matching cows would look! Train them to march in step, or even to moo at a specific pitch of the scale of musical notes- I give you "The Bells of St. Mary" on the cow organ... (video of a guy walking up to a line of cows arranged like a piano keyboard, carrying a pointed stick...)

Who says science never delivers? :-)

[Kathy Smith]

Can't some scientist just give us the real reason to why?:D

Instead of cloning cows and stuff why not find out why we are the way we are?

It's a horrible thought, Marleena; we, collectively, almost certainly know far more about this subject than all the world's scientists put together. We are the experts. If we can't figure it out then that's it! :)