Cerebral white matter blood flow is constant during human non-rapid eye movement sleep: a positron emission tomographic study.
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.
Hiroki
Masahiko
M
Human Brain Research Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Japan. CYI01752@nifty.com
Uema
Takeshi
T
Kajimura
Naofumi
N
Ogawa
Kenichi
K
Nishikawa
Masami
M
Kato
Masaaki
M
Watanabe
Tsuyoshi
T
Nakajima
Toru
T
Takano
Harumasa
H
Imabayashi
Etsuko
E
Ohnishi
Takashi
T
Takayama
Yutaka
Y
Matsuda
Hiroshi
H
Uchiyama
Makoto
M
Okawa
Masako
M
Takahashi
Kiyohisa
K
Fukuyama
Hidenao
H
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*