Cross-sex hormone treatment and own-body perception: behavioral and brain connectivity profiles
Behzad S. Khorashad, Amirhossein Manzouri, Jamie D. Feusner, Ivanka Savic
Scientific Reports February 7, 2021 DOI: 10.1038/s41598-020-80687-2 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 80 |
| Population | Transgender individuals (transmen and transwomen) and cisgender controls |
| Intervention | cross-sex hormone treatment |
| Key findings | Pretreatment, transmen and transwomen showed weaker functional connectivity in the default mode and salience networks and lower self-identification on a body morph test compared to cisgender controls; after cross-sex hormone treatment, connectivity and self-identification increased and group differences disappeared. |
Abstract
Abstract Referrals for gender dysphoria (GD), characterized by a distressful incongruence between gender identity and at-birth assigned sex, are steadily increasing. The underlying neurobiology, and the mechanisms of the often-beneficial cross-sex hormone treatment are unknown. Here, we test hypothesis that own body perception networks (incorporated in the default mode network—DMN, and partly in the salience network—SN), are different in trans-compared with cis-gender persons. We also investigate whether these networks change with cross-sex hormone treatment. Forty transmen (TrM) and 25 transwomen (TrW) were scanned before and after cross-sex hormone institution. We used our own developed Body Morph test (BM), to assess the perception of own body as self. Fifteen cisgender persons were controls. Within and between-group differences in functional connectivity were calculated using independent components analysis within the DMN, SN, and motor network (a control network). Pretreatment, TrM and TrW scored lower “self” on the BM test than controls. Their functional connections were weaker in the anterior cingulate-, mesial prefrontal-cortex (mPFC), precuneus, the left angular gyrus, and superior parietal cortex of the DMN, and ACC in the SN “Self” identification and connectivity in the mPFC in both TrM and TrW increased from scan 1 to 2, and at scan 2 no group differences remained. The neurobiological underpinnings of GD seem subserved by cerebral structures composing major parts of the DMN.