Testosterone Effects on the Brain in Transgender Men.
Transgender individuals experience incongruence between their gender identity and birth-assigned sex. The resulting gender dysphoria (GD), which some gender-incongruent individuals experience, is theorized to be a consequence of atypical cerebral sexual differentiation, but support for this assertion is inconsistent. We recently found that GD is associated with disconnected networks involved in self-referential thinking and own body perception. Here, we investigate how these networks in trans men (assigned female at birth with male gender identity) are affected by testosterone. In 22 trans men, we obtained T1-weighted, diffusion-weighted, and resting-state functional magnetic resonance imaging scans before and after testosterone treatment, measuring cortical thickness (Cth), subcortical volumes, fractional anisotropy (FA), and functional connectivity. Nineteen cisgender controls (male and female) were also scanned twice. The medial prefrontal cortex (mPFC) was thicker in trans men than controls pretreatment, and remained unchanged posttreatment. Testosterone treatment resulted in increased Cth in the insular cortex, changes in cortico-cortical thickness covariation between mPFC and occipital cortex, increased FA in the fronto-occipital tract connecting these regions, and increased functional connectivity between mPFC and temporo-parietal junction, compared with controls. Concluding, in trans men testosterone treatment resulted in functional and structural changes in self-referential and own body perception areas.
Department of Women's and Children's Health, Karolinska Institutet and University Hospital, SE-171 76 Stockholm, Sweden.
Sarah M
SM
Burke
Stressmotagningen, 112 38 Stockholm, Sweden.
Amir H
AH
Manzouri
ANOVA, Center of Expertise in Andrology, Sexual Medicine, and Transgender Medicine, Karolinska University Hospital, SE-171 76 Stockholm, Sweden.|Center for Psychiatric Research, Department of Clinical Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
Cecilia
C
Dhejne
Department of Women's and Children's Health, Karolinska Institutet and University Hospital, SE-171 76 Stockholm, Sweden.
Karin
K
Bergström
ANOVA, Center of Expertise in Andrology, Sexual Medicine, and Transgender Medicine, Karolinska University Hospital, SE-171 76 Stockholm, Sweden.|Department of Medicine/Huddinge, Karolinska Institutet, SE-141 86 Stockholm, Sweden.
Stefan
S
Arver
Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA 90095, USA.
Jamie D
JD
Feusner
Department of Women's and Children's Health, Karolinska Institutet and University Hospital, SE-171 76 Stockholm, Sweden.
Ivanka
I
Savic-Berglund
D000293:Adolescent; D000328:Adult; D000728:Androgens; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000187:drug effects; D009434:Neural Pathways / Q000000981:diagnostic imaging / Q000187:drug effects*; D010100:Oxygen / Q000097:blood; D012649:Self Concept; D013739:Testosterone / Q000378:metabolism / Q000494:pharmacology*; D063106:Transgender Persons / Q000523:psychology; D055815:Young Adult
D000728:Androgens; D013739:Testosterone; D010100:Oxygen