TY - JOUR

T1 - Inverse correlation of fluctuations of cerebral blood and water concentrations in humans

AU - Borchardt, Viola

AU - Korhonen, Vesa

AU - Helakari, Heta

AU - Nedergaard, Maiken

AU - Myllylä, Teemu

AU - Kiviniemi, Vesa

N1 - Publisher Copyright: © 2021, The Author(s).

PY - 2021

Y1 - 2021

N2 - Near-infrared spectroscopy (fNIRS) measures concentrations of oxygenated (HbO) and deoxygenated (HbR) hemoglobin in the brain. Recently, we demonstrated its potential also for measuring concentrations of cerebral water (cH 2O). We performed fNIRS measurements during rest to study fluctuations in concentrations of cH 2O , HbO and HbR in 33 well-rested healthy control subjects (HC) and 18 acutely sleep-deprived HC. Resting-state fNIRS signal was filtered in full-band, cardiac, respiratory, low-, and very-low-frequency bands. The sum of HbO and HbR constitutes the regional cerebral blood volume (CBV). CBV and cH 2O concentrations were analyzed via temporal correlation and phase synchrony. Fluctuation in concentrations of cH 2O and CBV was strongly anti-correlated across all frequency bands in both frontal and parietal cortices. Fluctuation in concentrations of cH 2O and CBV showed neither a completely synchronous nor a random phase relationship in both frontal and parietal cortices. Acutely sleep-deprived subjects did not show significant differences in temporal correlation or phase synchrony between fluctuations in cH 2O and CBV concentrations compared with well-rested HC. The reciprocal interrelation between fluctuations in CBV and cH 2O concentrations is consistent with the Munro–Kellie doctrine of constant intracranial volume. This coupling may constitute a functional mechanism underlying glymphatic circulation, which persists despite acutely disturbed sleep patterns.

AB - Near-infrared spectroscopy (fNIRS) measures concentrations of oxygenated (HbO) and deoxygenated (HbR) hemoglobin in the brain. Recently, we demonstrated its potential also for measuring concentrations of cerebral water (cH 2O). We performed fNIRS measurements during rest to study fluctuations in concentrations of cH 2O , HbO and HbR in 33 well-rested healthy control subjects (HC) and 18 acutely sleep-deprived HC. Resting-state fNIRS signal was filtered in full-band, cardiac, respiratory, low-, and very-low-frequency bands. The sum of HbO and HbR constitutes the regional cerebral blood volume (CBV). CBV and cH 2O concentrations were analyzed via temporal correlation and phase synchrony. Fluctuation in concentrations of cH 2O and CBV was strongly anti-correlated across all frequency bands in both frontal and parietal cortices. Fluctuation in concentrations of cH 2O and CBV showed neither a completely synchronous nor a random phase relationship in both frontal and parietal cortices. Acutely sleep-deprived subjects did not show significant differences in temporal correlation or phase synchrony between fluctuations in cH 2O and CBV concentrations compared with well-rested HC. The reciprocal interrelation between fluctuations in CBV and cH 2O concentrations is consistent with the Munro–Kellie doctrine of constant intracranial volume. This coupling may constitute a functional mechanism underlying glymphatic circulation, which persists despite acutely disturbed sleep patterns.

U2 - 10.1140/epjp/s13360-021-01480-2

DO - 10.1140/epjp/s13360-021-01480-2

M3 - Journal article

AN - SCOPUS:85105458704

VL - 136

JO - Nuovo Cimento della Societa Italiana di Fisica B

JF - Nuovo Cimento della Societa Italiana di Fisica B

SN - 2190-5444

IS - 5

M1 - 497

ER -