title: Resting states are resting traits--an FMRI study of sex differences and menstrual cycle effects in resting state cognitive control networks.
abstract: To what degree resting state fMRI is stable or susceptible to internal mind states of the individual is currently an issue of debate. To address this issue, the present study focuses on sex differences and investigates whether resting state fMRI is stable in men and women or changes within relative short-term periods (i.e., across the menstrual cycle). Due to the fact that we recently reported menstrual cycle effects on cognitive control based on data collected during the same sessions, the current study is particularly interested in fronto-parietal resting state networks. Resting state fMRI was measured in sixteen women during three different cycle phases (menstrual, follicular, and luteal). Fifteen men underwent three sessions in corresponding time intervals. We used independent component analysis to identify four fronto-parietal networks. The results showed sex differences in two of these networks with women exhibiting higher functional connectivity in general, including the prefrontal cortex. Menstrual cycle effects on resting states were non-existent. It is concluded that sex differences in resting state fMRI might reflect sexual dimorphisms in the brain rather than transitory activating effects of sex hormones on the functional connectivity in the resting brain.
authors: Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.
authors: Helene
authors: H
authors: Hjelmervik
authors: Department of Psychology, Durham University, Durham, United Kingdom.
authors: Markus
authors: M
authors: Hausmann
authors: Bjørgvin District Psychiatric Centre, Haukeland University Hospital, Bergen, Norway.
authors: Berge
authors: B
authors: Osnes
authors: Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors: René
authors: R
authors: Westerhausen
authors: Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway; Department of Medical Engineering, Haukeland University Hospital, Bergen, Norway.
authors: Karsten
authors: K
authors: Specht
mesh_terms: D000328:Adult; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008597:Menstrual Cycle / Q000502:physiology*; D009434:Neural Pathways; D017397:Prefrontal Cortex / Q000502:physiology*; D012146:Rest / Q000502:physiology*; D012727:Sex Characteristics; D055815:Young Adult