The slow (<1 Hz) rhythm of non-REM sleep: a dialogue between three cardinal oscillators

Abstract

The slow (<1 Hz) rhythm, the most substantial EEG signature of non–rapid eye movement (NREM) sleep, is generally viewed as originating exclusively from neocortical networks. The authors propose that this oscillation requires the interaction of a cortical oscillator and two thalamic ones. The slow (<1 Hz) rhythm, the most important electroencephalogram (EEG) signature of non–rapid eye movement (NREM) sleep, is generally viewed as originating exclusively from neocortical networks. Here we argue that the full manifestation of this fundamental sleep oscillation in a corticothalamic module requires the dynamic interaction of three cardinal oscillators: one predominantly synaptically based cortical oscillator and two intrinsic, conditional thalamic oscillators. The functional implications of this hypothesis are discussed in relation to other EEG features of NREM sleep, with respect to coordinating activities in local and distant neuronal assemblies and in the context of facilitating cellular and network plasticity during slow-wave sleep.