Mueller Sven C, Landré Lionel, Wierckx Katrien, T'Sjoen Guy
Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium.
Neuroendocrinology. 2017;105(2):123-130. doi: 10.1159/000448787. Epub 2016 Aug 5.
To date, research findings are inconsistent about whether the neuroanatomy in transgender persons resembles that of their natal sex or their gender identity. Moreover, few studies have examined the effects of long-term cross-sex hormonal treatment on neuroanatomy in this cohort. The purpose of the present study was to examine neuroanatomical differences in transgender persons after prolonged cross-sex hormone therapy.
Eighteen transgender men (female-to-male), 17 transgender women (male-to-female), 30 nontransgender men (natal men), and 27 nontransgender women (natal women) completed a high-resolution structural magnetic resonance imaging scan at 3 T. Eligibility criteria for transgender persons were gender-affirming surgery and at least 2 years of cross-sex hormone therapy. Exclusion criteria for nontransgender persons were presence of psychiatric or neurological disorders.
The mean neuroanatomical volume for the amygdala, putamen, and corpus callosum differed between transgender women and natal women but not between transgender women and natal men. Differences between transgender men and natal men were found in several brain structures, including the medial temporal lobe structures and cerebellum. Differences between transgender men and natal women were found in the medial temporal lobe, nucleus accumbens, and 3rd ventricle. Sexual dimorphism between nontransgender men and women included larger cerebellar volumes and a smaller anterior corpus callosum in natal men than in natal women. The results remained stable after correcting for additional factors including age, total intracranial volume, anxiety, and depressive symptoms.
Neuroanatomical differences were region specific between transgender persons and their natal sex as well as their gender identity, raising the possibility of a localized influence of sex hormones on neuroanatomy.
迄今为止，关于跨性别者的神经解剖结构是与其出生时的性别还是与其性别认同相似，研究结果并不一致。此外，很少有研究考察长期跨性别激素治疗对该群体神经解剖结构的影响。本研究的目的是探讨长期跨性别激素治疗后跨性别者的神经解剖差异。
18名跨性别男性（女性变男性）、17名跨性别女性（男性变女性）、30名非跨性别男性（出生时为男性）和27名非跨性别女性（出生时为女性）在3T条件下完成了高分辨率结构磁共振成像扫描。跨性别者的纳入标准为性别确认手术和至少2年的跨性别激素治疗。非跨性别者的排除标准为存在精神或神经疾病。
跨性别女性和出生时为女性的非跨性别女性之间，杏仁核、壳核和胼胝体的平均神经解剖体积存在差异，但跨性别女性和出生时为男性的非跨性别男性之间没有差异。跨性别男性和出生时为男性的非跨性别男性之间在几个脑结构中存在差异，包括内侧颞叶结构和小脑。跨性别男性和出生时为女性的非跨性别女性之间在内侧颞叶、伏隔核和第三脑室存在差异。非跨性别男性和女性之间的性别二态性包括出生时为男性的非跨性别男性的小脑体积较大，胼胝体前部较小。在校正包括年龄、总颅内体积、焦虑和抑郁症状在内的其他因素后，结果仍然稳定。
跨性别者与其出生时的性别以及性别认同之间的神经解剖差异具有区域特异性，这增加了性激素对神经解剖结构产生局部影响的可能性。
