White matter microstructure in transsexuals and controls investigated by diffusion tensor imaging

Georg Kranz, A. Hahn, U. Kaufmann, M. Küblböck, A. Hummer, S. Ganger, R. Seiger, D. Winkler, D.F. Swaab, C. Windischberger, S. Kasper, R. Lanzenberger

Research output: Journal article publicationJournal articleAcademic researchpeer-review

61 Citations (Scopus)

Abstract

© 2014 the authors.Biological causes underpinning the well known gender dimorphisms in human behavior, cognition, and emotion have received increased attention in recent years. The advent of diffusion-weighted magnetic resonance imaging has permitted the investigation of the white matter microstructure in unprecedented detail. Here, we aimed to study the potential influences of biological sex, gender identity, sex hormones, and sexual orientation on white matter microstructure by investigating transsexuals and healthy controls using diffusion tensor imaging (DTI). Twenty-three female-to-male (FtM) and 21 male-to-female (MtF) transsexuals, as well as 23 female (FC) and 22 male (MC) controls underwent DTI at 3 tesla. Fractional anisotropy, axial, radial, and mean diffusivity were calculated using tract-based spatial statistics (TBSS) and fiber tractography. Results showed widespread significant differences in mean diffusivity between groups in almost all white matter tracts. FCs had highest mean diffusivities, followed by FtM transsexuals with lower values, MtF transsexuals with further reduced values, and MCs with lowest values. Investigating axial and radial diffusivities showed that a transition in axial diffusivity accounted for mean diffusivity results. No significant differences in fractional anisotropymapswere found between groups. Plasma testosterone levels were strongly correlated withmean, axial, and radial diffusivities. However, controlling for individual estradiol, testosterone, or progesterone plasma levels or for subjects' sexual orientation did not change group differences. Our data harmonize with the hypothesis that fiber tract development is influenced by the hormonal environment during late prenatal and early postnatal brain development.
Original languageEnglish
Pages (from-to)15466-15475
Number of pages10
JournalJournal of Neuroscience
Volume34
Issue number46
DOIs
Publication statusPublished - 1 Jan 2014
Externally publishedYes

Keywords

  • Diffusion tensor imaging
  • Gender identity disorder
  • Testosterone
  • Transsexual
  • White matter microstructure

ASJC Scopus subject areas

  • Neuroscience(all)

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