title: Lack of sex effect on brain activity during a visuomotor response task: functional MR imaging study.
abstract: OBJECTIVE
  As more individuals are enrolled in clinical functional MR imaging (fMRI) studies, an understanding of how sex may influence fMRI-measured brain activation is critical.
  
  
  METHODS
  We used fixed- and random-effects models to study the influence of sex on fMRI patterns of brain activation during a simple visuomotor reaction time task in the group of 26 age-matched men and women. We evaluated the right visual, left visual, left primary motor, left supplementary motor, and left anterior cingulate areas.
  
  
  RESULTS
  Volumes of activations did not significantly differ between the groups in any defined regions. Analysis of variance failed to show any significant correlations between sex and volumes of brain activation in any location studied. Mean percentage signal-intensity changes for all locations were similar between men and women. A two-way t test of brain activation in men and women, performed as a part of random-effects modeling, showed no significant difference at any site.
  
  
  CONCLUSIONS
  Our results suggest that sex seems to have little influence on fMRI brain activation when we compared performance on the simple reaction-time task. The need to control for sex effects is not critical in the analysis of this task with fMRI.
authors.affiliation: Johns Hopkins Hospital, the Russell H. Morgan Department of Radiology and Radiological Sciences, Division of Neuroradiology, Baltimore, MD 21205, USA.
authors.forename: Nina
authors.initials: N
authors.lastname: Mikhelashvili-Browner
authors.forename: David M
authors.initials: DM
authors.lastname: Yousem
authors.forename: Colin
authors.initials: C
authors.lastname: Wu
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kraut
authors.forename: Christina L
authors.initials: CL
authors.lastname: Vaughan
authors.forename: Kader Karli
authors.initials: KK
authors.lastname: Oguz
authors.forename: Vince D
authors.initials: VD
authors.lastname: Calhoun
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology*; D005260:Female; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D012727:Sex Characteristics; D014793:Visual Cortex / Q000502:physiology