TESTOSTERONE CHANGES SPEECH PATHWAYS, OR: MEN AND WOMEN COMMUNICATE DIFFERENTLY
Women who wish to become male (known as “sex reassignment”) undergo a “testosterone therapy”, the objective being to raise the amount of testosterone (i.e., the male hormone) thus lowering the ratio of testosterone to estrogen (i.e., the female hormone).  This therapy requires continuous, high-dose injections of the hormone as testosterone has a half-life of 70 minutes in the blood. Recent studies of brain scans from these transgender women show changes in the structures of their brains and, in particular, in the pathways associated with speech and verbal fluency.
It is been known for some time that testosterone influences verbal fluency. Because of ethical reasons, prior studies have been mostly observational in nature and thus have limited scientists in their hypotheses. However, as more women (and men) undergo sex reassignment (and it becomes more “mainstream” mostly due to the press surrounding Caitlyn Jenner, née Bruce Jenner), scientists have been able to follow the impact of testosterone on speech pathways.
Austrian and Dutch researchers followed 18 female-to-male subjects administering MRI brain scans before and after 4 weeks of being given testosterone. In every instance, grey matter volume in two specific regions of the brain, the Broca’s and Wernicke’s areas, was found to have decreased. These areas are known to be the main language processing centers. Simultaneously, the neuronal pathway connecting these two regions were found to have gotten stronger
“[H]igher testosterone is linked to smaller vocabulary in children and that verbal fluency skills decrease in female-to-male transsexuals after testosterone treatment” said Dr. Andreas Hahn.
“What we see is a real quantitative difference in brain structure after prolonged exposure to testosterone. [T]hese findings may suggest that the genuine difference between the brains of women and men is substantially attributable to the effects of circulating sex hormones“ said Prof. Rupert Lanzenberger.
Dr. Kamilla Miskowiak said: “It is well-known that language development differs between girls and boys and that this is related to gender-related differences in brain maturation. However, this intriguing neuro-imaging study of transsexuals before and after their female-to-male gender reassignment suggests that even adult men and women differ in brain structure within regions involved in language and speech. In particular, female-to-male gender reassignment resulted in local brain matter decrease within language processing regions, which may explain why verbal abilities are often stronger in women.”
We have previously reviewed (see, http://heartwhisper.us/on-being-one-and-of-the-genetic-evolution-of-men-women-communication-part-i/) the evolutionary differences between men and women communication styles. We have known for some time that women evolved to use speech as a way to create bonds and as a reward mechanism. That’s why women use silence as a form of punishment. Unfortunately, most men view silence as a sort of reward. Men, on the other hand, evolved to use speech as a way to identify problems so they could be resolved. In other words, women are emotional speakers, whereas men are rational speakers. As such, we are prone to mis-communicate which leads to stress in, and often the end of, relationships. Learning how each sex communicates and using this information can create long-lived, healthy and loving relationships. For more information see: http://heartwhisper.us/.
 A detailed review of sex reassignment therapies and side effects can be viewed at: https://en.wikipedia.org/wiki/Hormone_replacement_therapy_(female-to-male) and http://www.femaletomale.org/ftm-transitioning-guide/testosterone-hrt/
As always, I welcome your comments.