Augmenting hippocampal–prefrontal neuronal synchrony during sleep enhances memory consolidation in humans

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 […]

Parp1 promotes sleep, which enhances DNA repair in neurons

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 […]

Claustral Projections to Anterior Cingulate Cortex Modulate Engagement with the External World

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 […]

Selective neuronal lapses precede human cognitive lapses following sleep deprivation

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 Sleep Slow-Wave Activity Increase After Extended Wake? Assessing the Effects of Increased Cortical Firing During Wake and Sleep

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 […]

Single-neuron activity and eye movements during human REM sleep and awake vision

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. […]