Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, 300 UCLA Medical Plaza, suite 2200, Los Angeles, CA, 90095, USA.
Department of Womens and Childrens Health and Neurology Clinic, Karolinska Institute and University Hospital, Q2:07 SE, 171 76, Stockholm, Sweden.
Brain Imaging Behav. 2017 Aug;11(4):964-976. doi: 10.1007/s11682-016-9578-6.
Gender dysphoria (GD) is characterized by incongruence between one's identity and gender assigned at birth. The biological mechanisms of GD are unclear. We investigated brain network connectivity patterns involved in own body perception in the context of self in GD. Twenty-seven female-to-male (FtM) individuals with GD, 27 male controls, and 27 female controls underwent resting state fMRI. We compared functional connections within intrinsic connectivity networks involved in self-referential processes and own body perception -default mode network (DMN) and salience network - and visual networks, using independent components analyses. Behavioral correlates of network connectivity were also tested using self-perception ratings while viewing own body images morphed to their sex assigned at birth, and to the sex of their gender identity. FtM exhibited decreased connectivity of anterior and posterior cingulate and precuneus within the DMN compared with controls. In FtM, higher "self" ratings for bodies morphed towards the sex of their gender identity were associated with greater connectivity of the anterior cingulate within the DMN, during long viewing times. In controls, higher ratings for bodies morphed towards their gender assigned at birth were associated with right insula connectivity within the salience network, during short viewing times. Within visual networks FtM showed weaker connectivity in occipital and temporal regions. Results suggest disconnectivity within networks involved in own body perception in the context of self in GD. Moreover, perception of bodies in relation to self may be reflective rather than reflexive, as a function of mesial prefrontal processes. These may represent neurobiological correlates to the subjective disconnection between perception of body and self-identification.
性别焦虑症（GD）的特征是个体的身份与出生时分配的性别不一致。GD 的生物学机制尚不清楚。我们研究了 GD 中自我参照过程和自身身体感知所涉及的脑网络连接模式。27 名女性到男性（FtM）GD 个体、27 名男性对照和 27 名女性对照接受了静息状态 fMRI 检查。我们使用独立成分分析比较了自我参照过程和自身身体感知所涉及的内在连接网络的功能连接——默认模式网络（DMN）和突显网络——以及视觉网络。还使用自我感知评分测试了网络连接的行为相关性，同时观察自己的身体图像被变形为出生时分配的性别和自己的性别认同的性别。与对照组相比，FtM 的 DMN 中的前扣带和后扣带以及楔前叶的连接性降低。在 FtM 中，对于朝向其性别认同的性别的身体的“自我”评分越高，与 DMN 内前扣带的连接性越强，在长时间观看时。在对照组中，对于朝向其出生时分配的性别的身体的评分越高，与短时间观看时右侧岛叶的突显网络内连接性越强。在视觉网络中，FtM 在枕叶和颞叶区域的连接性较弱。结果表明，GD 中自我参照过程和自身身体感知所涉及的网络连接中断。此外，身体相对于自我的感知可能是反射性的，而不是反射性的，这是内侧前额叶过程的功能。这些可能代表了身体感知与自我认同之间主观脱节的神经生物学相关性。
