Cerebral glucose utilization during stage 2 sleep in man.
Using [18F]fluorodeoxyglucose method and positron emission tomography, we performed paired determinations of the cerebral glucose utilization at one week intervals during sleep and wakefulness, in 12 young normal subjects. During 6 of 28 sleep runs, a stable stage 2 SWS was observed that fulfilled the steady-state conditions of the model. The cerebral glucose utilization during stage 2 SWS was lower than during wakefulness, but the variation did not significantly differ from zero (mean variation: -11.5 +/- 25.57%, P = 0.28). The analysis of 89 regions of interest showed that glucose metabolism differed significantly from that observed at wake in 6 brain regions, among them both thalamic nuclei. We conclude that the brain energy metabolism is not homogeneous throughout all the stages of non-REMS but decreases from stage 2 SWS to deep SWS; we suggest that a low thalamic glucose metabolism is a metabolic feature common to both stage 2 and deep SWS, reflecting the inhibitory processes observed in the thalamus during these stages of sleep. Stage 2 SWS might protect the stability of sleep by insulating the subject from the environment and might be a prerequisite to the full development of other phases of sleep, especially deep SWS.
Maquet
P
P
Department of Neurology, University of Liège, CHU Sart Tilman, Belgium.
Dive
D
D
Salmon
E
E
Sadzot
B
B
Franco
G
G
Poirrier
R
R
Franck
G
G
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D003847:Deoxyglucose / Q000031:analogs & derivatives; D019788:Fluorodeoxyglucose F18; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology; D014055:Tomography, Emission-Computed
D019788:Fluorodeoxyglucose F18; D003847:Deoxyglucose; D005947:Glucose