Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm 171 77, Sweden.
MR Physics, Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Stockholm 171 76, Sweden.
Cereb Cortex. 2021 Jun 10;31(7):3184-3193. doi: 10.1093/cercor/bhaa412.
Gender incongruence (GI) is characterized by a feeling of estrangement from the own body in the context of self. GI is often described in people who identify as transgender. The underlying mechanisms are unknown. Data from MRI measurements and tests of own body perception triggered us to pose a model that GI in transgender persons (TGI) could be associated with a disconnection within the brain circuits mediating the perception of own body as self. This is a departure from a previous model of sex atypical cerebral dimorphism, introducing a concept that better accords with a core feature of TGI. The present MRI study of 54 hormone naive transmen (TrM), 38 transwomen (TrW), 44 cismen and 41 ciswomen show that cortical gyrification, a metric that reflects early maturation of cerebral cortex, is significantly lower in transgender compared with cisgender participants. This reduction is limited to the occipito-parietal cortex and the sensory motor cortex, regions encoding own body image and body ownership. Moreover, the cortical gyrification correlated inversely with own body-self incongruence in these regions. These novel data suggest that GI in TGI may originate in the neurodevelopment of body image encoding regions. The results add potentially to understanding neurobiological contributors to gender identity.
性别不一致（GI）的特点是在自我背景下对自身身体感到疏远。GI 通常在被认定为跨性别的人中描述。其潜在机制尚不清楚。来自 MRI 测量和自身身体感知测试的数据促使我们提出一个模型，即跨性别者（TGI）的 GI 可能与介导自身身体作为自我感知的大脑回路中的断开有关。这与以前的性非典型大脑二态性模型不同，提出了一个更好地符合 TGI 的核心特征的概念。本研究对 54 名激素未治疗的跨男性（TrM）、38 名跨女性（TrW）、44 名顺性别男性和 41 名顺性别女性进行了 MRI 研究，结果显示，皮质脑回（衡量大脑皮质早期成熟度的指标）在跨性别者中明显低于顺性别者。这种减少仅限于枕顶叶皮层和感觉运动皮层，这些区域编码自身身体形象和身体所有权。此外，这些区域的皮质脑回与自身身体-自我不一致性呈负相关。这些新数据表明，TGI 中的 GI 可能起源于身体形象编码区域的神经发育。这些结果可能有助于理解性别认同的神经生物学因素。
