title: Regional slow waves and spindles in human sleep.
abstract: The most prominent EEG events in sleep are slow waves, reflecting a slow (<1 Hz) oscillation between up and down states in cortical neurons. It is unknown whether slow oscillations are synchronous across the majority or the minority of brain regions--are they a global or local phenomenon? To examine this, we recorded simultaneously scalp EEG, intracerebral EEG, and unit firing in multiple brain regions of neurosurgical patients. We find that most sleep slow waves and the underlying active and inactive neuronal states occur locally. Thus, especially in late sleep, some regions can be active while others are silent. We also find that slow waves can propagate, usually from medial prefrontal cortex to the medial temporal lobe and hippocampus. Sleep spindles, the other hallmark of NREM sleep EEG, are likewise predominantly local. Thus, intracerebral communication during sleep is constrained because slow and spindle oscillations often occur out-of-phase in different brain regions.
authors.affiliation: Department of Psychiatry, University of Wisconsin-Madison, Madison, WI 53719, USA.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Nir
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Staba
authors.forename: Thomas
authors.initials: T
authors.lastname: Andrillon
authors.forename: Vladyslav V
authors.initials: VV
authors.lastname: Vyazovskiy
authors.forename: Chiara
authors.initials: C
authors.lastname: Cirelli
authors.forename: Itzhak
authors.initials: I
authors.lastname: Fried
authors.forename: Giulio
authors.initials: G
authors.lastname: Tononi
mesh_terms: D001921:Brain / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000503:physiopathology; D006801:Humans; D017286:Polysomnography / Q000379:methods; D012890:Sleep / Q000502:physiology*