Neuroimaging differences in spatial cognition between men and male-to-female transsexuals before and during hormone therapy.
BACKGROUND
Neuropsychological abnormalities in transsexual patients have been reported in comparison with subjects without gender identity disorder (GID), suggesting differences in underlying neurobiological processes. However, these results have not consistently been confirmed. Furthermore, studies on cognitive effects of cross-sex hormone therapy also yield heterogeneous results.


OBJECTIVE
We hypothesized that untreated transsexual patients differ from men without GID in activation pattern associated with a mental rotation task and that these differences may further increase after commencing of hormonal treatment.


METHODS
The present study investigated 11 male-to-female transsexual (MFTS) patients prior to cross-sex hormone therapy and 11 MFTS patients during hormone therapy in comparison with healthy men without GID. Using functional magnetic resonance imaging at 3-Tesla, a mental rotation paradigm with proven sexual dimorphism was applied to all subjects. Data were analyzed with SPM5.


METHODS
Patterns of brain activation associated with a mental rotation task.


RESULTS
The classical mental rotation network was activated in all three groups, but significant differences within this network were observed. Men without GID exhibited significantly greater activation of the left parietal cortex (BA 40), a key region for mental rotation processes. Both transsexual groups revealed stronger activation of temporo-occipital regions in comparison with men without GID.


CONCLUSIONS
Our results confirmed previously reported deviances of brain activation patterns in transsexual men from men without GID and also corroborated these findings in a group of transsexual patients receiving cross-sex hormone therapy. The present study indicates that there are a priori differences between men and transsexual patients caused by different neurobiological processes or task-solving strategies and that these differences remain stable over the course of hormonal treatment.
Schöning
Sonja
S
Department of Psychiatry, University of Muenster, Muenster, Germany. Sonja.Schoening@ukmuenster.de
Engelien
Almut
A
Bauer
Christine
C
Kugel
Harald
H
Kersting
Anette
A
Roestel
Cornelia
C
Zwitserlood
Pienie
P
Pyka
Martin
M
Dannlowski
Udo
U
Lehmann
Wolfgang
W
Heindel
Walter
W
Arolt
Volker
V
Konrad
Carsten
C
D000726:Androgen Antagonists / Q000008:administration & dosage*; D002540:Cerebral Cortex / Q000187:drug effects* / Q000503:physiopathology*; D017373:Cyproterone Acetate / Q000008:administration & dosage*; D003867:Depth Perception / Q000187:drug effects* / Q000502:physiology*; D004192:Discrimination, Psychological / Q000187:drug effects* / Q000502:physiology*; D004292:Dominance, Cerebral / Q000187:drug effects / Q000502:physiology; D004359:Drug Therapy, Combination; D004958:Estradiol / Q000008:administration & dosage* / Q000097:blood*; D005260:Female; D005783:Gender Identity; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D009949:Orientation / Q000187:drug effects* / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000187:drug effects* / Q000502:physiology*; D011340:Problem Solving / Q000187:drug effects* / Q000502:physiology*; D011374:Progesterone / Q000097:blood*; D012016:Reference Values; D013739:Testosterone / Q000097:blood*; D014189:Transsexualism / Q000503:physiopathology* / Q000601:surgery*
D000726:Androgen Antagonists; D013739:Testosterone; D011374:Progesterone; D017373:Cyproterone Acetate; D004958:Estradiol