title: Cerebral white matter blood flow is constant during human non-rapid eye movement sleep: a positron emission tomographic study.
abstract: This study aimed to identify brain regions with the least decreased cerebral blood flow (CBF) and their relationship to physiological parameters during human non-rapid eye movement (NREM) sleep. Using [(15)O]H(2)O positron emission tomography, CBF was measured for nine normal young adults during nighttime. As NREM sleep progressed, mean arterial blood pressure and whole brain mean CBF decreased significantly; arterial partial pressure of CO(2) and, selectively, relative CBF of the cerebral white matter increased significantly. Absolute CBF remained constant in the cerebral white matter, registering 25.9 +/- 3.8 during wakefulness, 25.8 +/- 3.3 during light NREM sleep, and 26.9 +/- 3.0 (ml.100 g(-1).min(-1)) during deep NREM sleep (P = 0.592), and in the occipital cortex (P = 0.611). The regression slope of the absolute CBF significantly differed with respect to arterial partial pressure of CO(2) between the cerebral white matter (slope 0.054, R = - 0.04) and frontoparietal association cortex (slope - 0.776, R = - 0.31) (P = 0.005) or thalamus (slope - 1.933, R = - 0.47) (P = 0.004) and between the occipital cortex (slope 0.084, R = 0.06) and frontoparietal association cortex (P = 0.021) or thalamus (P < 0.001), and, with respect to mean arterial blood pressure, between the cerebral white matter (slope - 0.067, R = - 0.10) and thalamus (slope 0.637, R = 0.31) (P = 0.044). The cerebral white matter CBF keeps constant during NREM sleep as well as the occipital cortical CBF, and may be specifically regulated by both CO(2) vasoreactivity and pressure autoregulation.
authors.affiliation: Human Brain Research Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan. CYI01752@nifty.com
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hiroki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Uema
authors.forename: Naofumi
authors.initials: N
authors.lastname: Kajimura
authors.forename: Kenichi
authors.initials: K
authors.lastname: Ogawa
authors.forename: Masami
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kato
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Watanabe
authors.forename: Toru
authors.initials: T
authors.lastname: Nakajima
authors.forename: Harumasa
authors.initials: H
authors.lastname: Takano
authors.forename: Etsuko
authors.initials: E
authors.lastname: Imabayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takayama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuda
authors.forename: Makoto
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Masako
authors.initials: M
authors.lastname: Okawa
authors.forename: Kiyohisa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Hidenao
authors.initials: H
authors.lastname: Fukuyama
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D006801:Humans; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods*; D012039:Regional Blood Flow / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology*; D013687:Telencephalon / Q000098:blood supply* / Q000378:metabolism*