title: Neural substrates activated by viewing others expressing fatigue: a magnetoencephalography study.
abstract: The neural substrates of the fatigue sensation have not been totally identified. Several lines of evidence demonstrate that seeing emotional changes in others activates brain regions involved in experiencing similar emotions. We hypothesized that there exists a mirror system regarding the fatigue sensation and that brain regions associated with the fatigue sensation may be activated by viewing other individuals expressing fatigue. In this study, we attempted to identify the neural substrates activated by viewing other fatigued individuals using magnetoencephalography (MEG). Twelve healthy participants were enrolled in our study after providing written informed consent. During MEG recordings, they viewed a set of pictures projected on a screen. The pictures, which were presented in a randomized order, were of a person with a fatigued or neutral facial expression. When participants viewed pictures of people with fatigued expressions, we were able to estimate equivalent current dipoles (ECDs) in the posterior cingulate cortex (PCC) in 9 of 12 participants approximately 300 ms after the onset of each picture presentation. When they viewed pictures of people with neutral expressions, we were not able to estimate corresponding ECDs for any participant. The PCC is the brain region activated by viewing others expressing fatigue, suggesting existence of the shared neural substrates of felt and observed fatigue.
authors.affiliation: Department of Physiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Osaka 545-8585, Japan. a.ishii@med.osaka-cu.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Ishii
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tanaka
authors.forename: Emi
authors.initials: E
authors.lastname: Yamano
authors.forename: Yasuyoshi
authors.initials: Y
authors.lastname: Watanabe
mesh_terms: D004645:Empathy / Q000502:physiology*; D005149:Facial Expression; D005221:Fatigue / Q000523:psychology*; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D056345:Theory of Mind / Q000502:physiology*; D055815:Young Adult