We examined which aspects of cortical processing are affected by sleep deprivation (SD), and whether they can already be identified in early sensory regions. We recorded spiking activity in rat auditory cortex along with polysomnography while presenting sounds during SD followed by recovery sleep. We found that certain aspects of auditory processing (frequency tuning, onset […]
Sleep helps stabilize long-term memories, for example declarative hippocampal-dependent memories have been suggested to benefit from synchronization of neuronal activity in hippocampus and cortex during NREM sleep. Working with epilepsy patients implanted with intracranial electrodes for clinical reasons, we studied this process with single neuron resolution. We used electrical pulses in the prefrontal cortex, precisely […]
The timing, duration, and quality of sleep are regulated by an interaction between the circadian clock and homeostatic sleep pressure, which builds up during extended wakefulness. Homeostatic factors are thought to accumulate with increasing duration and intensity of wakefulness prior to sleep. In this study, a combination of behavioral monitoring and EMG/EEG recording under a […]
Engagement is a major determinant of performance. Hyper-engagement risks impulsivity and is fatiguing over time, while hypo-engagement could lead to missed opportunities. Even in sleep, when engagement levels are minimal, sensory responsiveness varies. Thus, maintaining an optimal engagement level with the environment is a fundamental cognitive ability. In this study we investigated the activity of […]
A reduced responsiveness to external stimuli is the main characteristic of sleep. In this study we show that the LC, a small nucleus in the brainstem and the main source of noradrenaline, plays a central role in our ability to disconnect from the environment during sleep. We recorded rats cerebral cortical activity (Electroencephalogram; EEG) in […]
REM sleep is considered vital for supporting well-being and normal cognition. In 1984, Lavie and colleagues described the case of Y.C. – a man with a pontine lesion and near-total absence of REM sleep who led a normal life. Here, we set out to re-evaluate this individual’s REMS status 30 years after the original report, […]
Sleep deprivation has widespread health effects, including increased risk of hypertension, diabetes, obesity, heart attack, and stroke. In addition, it leads to car accidents and medical errors. During sleep deprivation, homeostatic and circadian processes interact to build up sleep pressure, which results in slow behavioral performance (cognitive lapses). Here we used intracranial electrodes to record […]
Why does slow wave activity (SWA) increase after extended wakefulness? it is due to neuronal “fatigue” or increased neuronal synchrony? We forced neurons in the mouse cortex to fire at high levels for 6 h in 2 different conditions: during active wake with exploration and during sleep, using local optogenetic stimulation. We find that neurons […]
Are rapid eye movements (REMs) in sleep associated with visual-like activity, as during wakefulness? Here we examined single-unit activities and intracranial EEG across the human MTL and neocortex during sleep and wakefulness, and during visual stimulation with fixation. During both sleep and wakefulness, REM onsets are associated with distinct intracranial potentials, reminiscent of PGO waves. […]
