Kim Gwang-Won, Kim Seok-Kwun, Jeong Gwang-Woo
Research Institute for Medical Imaging, Chonnam National University Medical School, Gwangju, 501-757, Republic of Korea.
Department of Plastic and Reconstructive Surgery, Dong-A University School of Medicine, Busan, 602-715, Republic of Korea.
Surg Radiol Anat. 2016 Mar;38(2):245-52. doi: 10.1007/s00276-015-1547-z. Epub 2015 Aug 29.
The purpose of this study was to evaluate the brain activation pattern associated with sexual orientation and its correlation with the level of the free testosterone (free T) in postoperative female-to-male (FtM) transsexuals using a 3.0-Tesla functional magnetic resonance imaging (fMRI).
Eleven postoperative FtM transsexuals with sex reassignment surgery underwent fMRI on a 3.0-T MR scanner. Brain activity was measured while viewing erotic male and female nude pictures.
The average level of free T in the FtM transsexuals was in the normal range of heterosexual men. The brain areas with predominant activities during viewing female nude pictures in contrast to male pictures included the hippocampus, parahippocampal gyrus, anterior cingulate gyrus, putamen, amygdala, hypothalamus, and insula (p < 0.005). The free T levels were positively correlated with the BOLD signal changes in the parahippocampal gyrus (Spearman's rho = 0.91, p < 0.001), hippocampus (rho = 0.90, p < 0.001), insula (rho = 0.68, p < 0.05), putamen (rho = 0.66, p < 0.05), and amygdala (rho = 0.64, p < 0.05). Compared to FtM transsexuals with deficient level of free T, the FtM transsexuals with normal range of free T showed significantly higher activities in the parahippocampal gyrus, hippocampus, insula, putamen, and amygdala during viewing female nude pictures (p < 0.005).
This study revealed the specific brain activation pattern associated with sexual orientation and its correlation with free T in the postoperative FtM transsexuals. These findings are applicable in understanding the neural mechanism on sexual arousal in FtM transsexuals and their sexual orientation in connection with the free T levels.
本研究旨在使用3.0特斯拉功能磁共振成像（fMRI）评估术后女变男（FtM）变性者与性取向相关的脑激活模式及其与游离睾酮（游离T）水平的相关性。
11名接受了性别重置手术的术后FtM变性者在3.0-T磁共振扫描仪上接受了fMRI检查。在观看男性和女性色情裸体图片时测量脑活动。
FtM变性者的游离T平均水平处于异性恋男性的正常范围内。与男性图片相比，观看女性裸体图片时主要活跃的脑区包括海马体、海马旁回、前扣带回、壳核、杏仁核、下丘脑和脑岛（p<0.005）。游离T水平与海马旁回（斯皮尔曼相关系数ρ=0.91，p<0.001）、海马体（ρ=0.90，p<0.001）、脑岛（ρ=0.68，p<0.05）、壳核（ρ=0.66，p<0.05）和杏仁核（ρ=0.64，p<0.05）的血氧水平依赖（BOLD）信号变化呈正相关。与游离T水平不足的FtM变性者相比，游离T水平在正常范围内的FtM变性者在观看女性裸体图片时，海马旁回、海马体、脑岛、壳核和杏仁核的活动明显更高（p<0.005）。
本研究揭示了术后FtM变性者与性取向相关的特定脑激活模式及其与游离T的相关性。这些发现有助于理解FtM变性者性唤起的神经机制以及他们与游离T水平相关的性取向。
