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Neurology Research International
Volume 2010 (2010), Article ID 671421, 5 pages
Research Article

Medial Orbitofrontal Cortex Is Associated with Fatigue Sensation

1Hyogo Children's Sleep and Development Medical Research Center, Hyogo Rehabilitation Centre Central Hospital, 1070 Akebono-cho, Nishi-ku, Kobe 651-2181, Japan
2Research Center for Child Mental Development, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, Shizuoka 431-3192, Japan
3Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan
4Center for Molecular Imaging Science, RIKEN Kobe Institute, 6-7 Minatoshima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
5Department of Psychiatry, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
6Central Research Laboratory, Hamamatsu Photonics, 5000 Hirakuchi, Hamamatsu, Shizuoka 434-8601, Japan
7Department of Health Sciences, Faculty of Health Sciences for Welfare, Kansai University of Welfare Sciences, 3-11-1 Asahigaoka, Kashihara, Osaka 582-0026, Japan
8Laboratory of Human Imaging Research, Molecular Imaging Frontier Research Center, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan

Received 1 October 2009; Revised 19 March 2010; Accepted 18 April 2010

Academic Editor: Richard Maddock

Copyright © 2010 Seiki Tajima et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Fatigue is an indispensable bioalarm to avoid exhaustive state caused by overwork or stresses. It is necessary to elucidate the neural mechanism of fatigue sensation for managing fatigue properly. We performed positron emission tomography scans to indicate neural activations while subjects were performing 35-min fatigue-inducing task trials twice. During the positron emission tomography experiment, subjects performed advanced trail-making tests, touching the target circles in sequence located on the display of a touch-panel screen. In order to identify the brain regions associated with fatigue sensation, correlation analysis was performed using statistical parametric mapping method. The brain region exhibiting a positive correlation in activity with subjective sensation of fatigue, measured immediately after each positron emission tomography scan, was located in medial orbitofrontal cortex (Brodmann's area 10/11). Hence, the medial orbitofrontal cortex is a brain region associated with mental fatigue sensation. Our findings provide a new perspective on the neural basis of fatigue.