title: Decoding gender dimorphism of the human brain using multimodal anatomical and diffusion MRI data.
abstract: The female brain contains a larger proportion of gray matter tissue, while the male brain comprises more white matter. Findings like these have sparked increasing interest in studying dimorphism of the human brain: the general effect of gender on aspects of brain architecture. To date, the vast majority of imaging studies is based on unimodal MR images and typically limited to a small set of either gray or white matter regions-of-interest. The morphological content of magnetic resonance (MR) images, however, strongly depends on the underlying contrast mechanism. Consequently, in order to fully capture gender-specific morphological differences in distinct brain tissues, it might prove crucial to consider multiple imaging modalities simultaneously. This study introduces a novel approach to perform such multimodal classification incorporating the relative strengths of each modality-specific physical aperture to tissue properties. To illustrate our approach, we analyzed multimodal MR images (T(1)-, T(2)-, and diffusion-weighted) from 121 subjects (67 females) using a linear support vector machine with a mass-univariate feature selection procedure. We demonstrate that the combination of different imaging modalities yields a significantly higher balanced classification accuracy (96%) than any one modality by itself (83%-88%). Our results do not only confirm previous morphometric findings; crucially, they also shed new light on the most discriminative features in gray-matter volume and microstructure in cortical and subcortical areas. Specifically, we find that gender disparities are primarily distributed along brain networks thought to be involved in social cognition, reward-based learning, decision-making, and visual-spatial skills.
authors.affiliation: Max Planck Institute for Neurological Research, Gleueler Straße 50, 50931 Cologne, Germany. dfeis@nf.mpg.de
authors.forename: Delia-Lisa
authors.initials: DL
authors.lastname: Feis
authors.forename: Kay H
authors.initials: KH
authors.lastname: Brodersen
authors.forename: D Yves
authors.initials: DY
authors.lastname: von Cramon
authors.forename: Eileen
authors.initials: E
authors.lastname: Luders
authors.forename: Marc
authors.initials: M
authors.lastname: Tittgemeyer
mesh_terms: D000328:Adult; D001921:Brain / Q000033:anatomy & histology*; D001931:Brain Mapping; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D012727:Sex Characteristics; D055815:Young Adult