title: Increased oxygenation of the cerebral prefrontal cortex prior to the onset of voluntary exercise in humans.
abstract: To determine whether output from the forebrain (termed central command) may descend early enough to increase cardiac and renal sympathetic outflows at the onset of voluntary exercise, we examined the changes in regional tissue blood flows of bilateral prefrontal cortices with near-infrared spectroscopy, precisely identifying the onset of voluntary ergometer 30-s exercise at 41 ± 2% of the maximal exercise intensity in humans. Prefrontal oxygenated-hemoglobin (Oxy-Hb) concentration was measured as index of regional blood flow unless deoxygenated-hemoglobin concentration remained unchanged. Prefrontal Oxy-Hb concentration increased significantly (P < 0.05) 5 s prior to the onset of exercise with arbitrary start, whereas such increase in prefrontal Oxy-Hb was absent before exercise abruptly started by a verbal cue. Furthermore, the increase in prefrontal Oxy-Hb observed at the initial 15-s period of exercise was greater with arbitrary start than cued start. The prefrontal Oxy-Hb, thereafter, decreased during the later period of exercise, irrespective of either arbitrary or cued start. The reduction in prefrontal Oxy-Hb had the same time course and response magnitude as that during motor-driven passive exercise. Cardiac output increased at the initial period of exercise, whereas arterial blood pressure and total peripheral resistance decreased. The depressor response was more pronounced (P < 0.05) with arbitrary start than cued start. Taken together, it is suggested that the increase in prefrontal Oxy-Hb observed prior to the onset of voluntary exercise may be in association with central command, while the later decrease in the Oxy-Hb during exercise may be in association with feedback stimulated by mechanical limb motion.
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and matsuk@hiroshima-u.ac.jp.
authors.forename: Kanji
authors.initials: K
authors.lastname: Matsukawa
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and.
authors.forename: Kei
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and.
authors.forename: Nan
authors.initials: N
authors.lastname: Liang
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and.
authors.forename: Kana
authors.initials: K
authors.lastname: Endo
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ohtani
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nakamoto
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and.
authors.forename: Rie
authors.initials: R
authors.lastname: Wakasugi
authors.affiliation: Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; and.
authors.forename: Akito
authors.initials: A
authors.lastname: Kadowaki
authors.affiliation: Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Komine
mesh_terms: D000328:Adult; D002560:Cerebrovascular Circulation / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D010108:Oxyhemoglobins / Q000378:metabolism; D017397:Prefrontal Cortex / Q000378:metabolism / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D012119:Respiration; D019265:Spectroscopy, Near-Infrared / Q000379:methods
chemical_list: D006454:Hemoglobins; D010108:Oxyhemoglobins; D010100:Oxygen
keywords: motor-driven passive exercise; near-infrared spectroscopy; regional cerebral blood flow; voluntary ergometer