title: Physical fatigue increases neural activation during eyes-closed state: a magnetoencephalography study.
abstract: BACKGROUND
  Fatigue, defined as difficulty initiating or sustaining voluntary activities, can be classified as physical or mental. In this study, we use magnetoencephalography (MEG) to quantify the effect of physical fatigue on neural activity under the condition of simulated physical load.
  
  
  METHODS
  Thirteen healthy right-handed male volunteers participated in this study. The experiment consisted of one fatigue-inducing physical task session performed between two MEG sessions. During the 10-min physical task session, participants performed maximum-effort handgrips with the left hand lasting 1 s every 4 s; during MEG sessions, 3-min recordings were made during the eyes-closed state. MEG data were analyzed using narrow-band adaptive spatial filtering methods.
  
  
  RESULTS
  Alpha-frequency band (8-13 Hz) power in the left postcentral gyrus, precentral gyrus, and middle frontal gyrus (Brodmann's areas 1, 2, 3, 4, 6, and 46) were decreased after performing the physical fatigue-inducing task.
  
  
  CONCLUSIONS
  These results show that performing the physical fatigue-inducing task caused activation of the left sensorimotor and prefrontal areas, manifested as decreased alpha-frequency band power in these brain areas. Our results increase understanding of the neural mechanisms of physical fatigue.
authors.affiliation: Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka city, Osaka, 545-8585, Japan. masa-t@msic.med.osaka-cu.ac.jp.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka city, Osaka, 545-8585, Japan. a.ishii@med.osaka-cu.ac.jp.
authors.forename: Akira
authors.initials: A
authors.lastname: Ishii
authors.affiliation: Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka city, Osaka, 545-8585, Japan. yywata@riken.jp.|RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe city, Hyogo, 650-0047, Japan. yywata@riken.jp.
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D001921:Brain / Q000502:physiology*; D058256:Brain Waves / Q000502:physiology*; D005143:Eyelids / Q000502:physiology*; D005221:Fatigue / Q000503:physiopathology*; D005625:Frontal Lobe / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D059906:Neuroimaging; D055815:Young Adult