Beta EEG reflects sensory processing in active wakefulness and homeostatic sleep drive in quiet wakefulness

Abstract

Markers of sleep drive (<10Hz; slow wave activity and theta) have been identified in the course of slow wave sleep (SWS) and wakefulness. So far, higher frequencies in the waking electroencephalogram have not been examined thoroughly as a function of sleep drive. Here, we measured EEG dynamics in epochs of active wake (AW; wake characterized by high muscle tone) or quiet wake (QW; wake characterized by low muscle tone). We hypothesized that the higher beta oscillations (15-35Hz, measured by local field potential and electroencephalography) represent fundamentally different processes in AW and QW. In AW, sensory-stimulation elevated beta activity in parallel with gamma (80-90Hz) activity, indicative of cognitive processing. In QW, beta activity paralleled slow wave activity (1-4Hz) and theta (5-8Hz) in tracking sleep need. Cerebral lactate concentration, a measure of cerebral glucose utilization, increased during AW whereas it declined during QW. Mathematical modeling of state-dependent dynamics of cortical lactate concentration was more precisely predictive when QW and AW were included as two distinct substates rather than a uniform state of wakefulness. The extent to which lactate concentration declined in QW and increased in AW was proportionate to the amount of beta activity. These data distinguish QW from AW. QW, particularly when characterized by beta activity, is permissive to metabolic and electrophysiological changes that occur in SWS. These data urge further studies on state dependent beta oscillations across species.

Sleep Homeostatic and Waking Behavioral Phenotypes inEgr3-Deficient Mice Associated with Serotonin Receptor 5-HT2 Deficits

“…The high intensity SWA and beta activity in Egr3-/-mice in the baseline condition was similar to that of WT mice in a condition of high sleep drive, 23 suggesting a reduced level of arousal during QW in Egr3-deficient mice relative to WT mice.…”

Rai1 frees mice from the repression of active wake behaviors by light

“…Also, the high beta/low gamma frequency band was more strongly activated by light in Rai1 +/- mice than in wild-type. This frequency range also increases progressively during prolonged waking in both human and mouse (Cajochen et al, 2002; Grønli et al, 2016) and has been associated with behavioral arrest and slower movements (Zheng et al, 2015), as well as with the motor deficits accompanying Parkinson disease (Weinberger et al, 2009; Mallet et al, 2008), suggesting that processes related to motor control are reflected in the waking EEG and might be relevant also for the light-induced suppression of locomotor activity in the SMS model.…”

Bidirectional and context-dependent changes in theta and gamma oscillatory brain activity in noradrenergic cell-specific Hypocretin/Orexin receptor 1-KO mice

“…Baseline waking was enriched in δ (1.25–2.75 Hz) frequencies, and upon EW and CC, in δ and inter-δ/θ frequencies, both of which reflect homeostatic sleep pressure in rodents and humans. Waking δ activity moreover correlates with declining cognitive performance during prolonged waking, and elevation of δ, θ/α, and β power, while γ power fades, correlate with subjective sleepiness 55 , 74 – 81 . Thus an increase in slow (infra-θ) oscillations in CKO mice suggests a less alert waking state, which appears to affect waking globally, as active waking (TDW) is also excessively δ-rich.…”