RT Journal Article
SR Electronic
T1 Coordinated infraslow neural and cardiac oscillations mark fragility and offline periods in mammalian sleep
JF Science Advances
JO Sci Adv
FD American Association for the Advancement of Science
SP e1602026
DO 10.1126/sciadv.1602026
VO 3
IS 2
A1 Lecci, Sandro
A1 Fernandez, Laura M. J.
A1 Weber, Frederik D.
A1 Cardis, Romain
A1 Chatton, Jean-Yves
A1 Born, Jan
A1 Lüthi, Anita
YR 2017
UL http://advances.sciencemag.org/content/3/2/e1602026.abstract
AB Rodents sleep in bouts lasting minutes; humans sleep for hours. What are the universal needs served by sleep given such variability? In sleeping mice and humans, through monitoring neural and cardiac activity (combined with assessment of arousability and overnight memory consolidation, respectively), we find a previously unrecognized hallmark of sleep that balances two fundamental yet opposing needs: to maintain sensory reactivity to the environment while promoting recovery and memory consolidation. Coordinated 0.02-Hz oscillations of the sleep spindle band, hippocampal ripple activity, and heart rate sequentially divide non–rapid eye movement (non-REM) sleep into offline phases and phases of high susceptibility to external stimulation. A noise stimulus chosen such that sleeping mice woke up or slept through at comparable rates revealed that offline periods correspond to raising, whereas fragility periods correspond to declining portions of the 0.02-Hz oscillation in spindle activity. Oscillations were present throughout non-REM sleep in mice, yet confined to light non-REM sleep (stage 2) in humans. In both species, the 0.02-Hz oscillation predominated over posterior cortex. The strength of the 0.02-Hz oscillation predicted superior memory recall after sleep in a declarative memory task in humans. These oscillations point to a conserved function of mammalian non-REM sleep that cycles between environmental alertness and internal memory processing in 20- to 25-s intervals. Perturbed 0.02-Hz oscillations may cause memory impairment and ill-timed arousals in sleep disorders.