Oscillatory-Quality of sleep spindles: from properties to function

Abstract

AbstractSleep spindles are traditionally defined as 10-15Hz thalamo-cortical oscillations typical of NREM sleep. While substantial heterogeneity in the appearance or spatio-temporal dynamics of spindle events is well recognised, the physiological relevance of the underlying fundamental property - the oscillatory strength - has not been studied. Here we introduce a novel metric calledoscillatory Quality(o-Quality), which is derived by fitting an auto-regressive model to short segments of electrophysiological signals, recorded from the cortex in mice, to identify and calculate the damping of spindle oscillations. We find that theo-Qualityof spindles varies markedly across cortical layers and regions and reflects the level of synchrony within and between cortical networks. Furthermore, theo-Qualityof spindles varies as a function of sleep-wake history, determines the strength of coupling between spindles and slow waves, and influences the responsiveness to sensory stimulation during sleep. Thus, theo-Qualityemerges as a metric that, for the first time, directly links the spatio-temporal dynamics of sleep spindles with their functional role.