REM sleep

To explore how supragranular cortical pyramidal cells (Pyrs) are recruited during natural sleep, we applied a method of juxtacellular recording/labeling in freely moving rats. We asked how different Pyrs activate during sleep events such as down-to-up-state transition (DUt), spindle (SO), and REM sleep-related theta oscillations (ThO). Based on the polarity of the down-states (DS) recorded along with the cell firing, we divided Pyrs as superficial (negative DS, layer 2 – L2, n=35) or deep (positive DS, layer 3 – L3, n=35). Most of the Pyrs showed very sporadic firing behavior, with a lower ave

Sleep is an essential process observed throughout the animal kingdom, and it is important for memory consolidation. Coordinated neuronal activity occurs during sleep, characterized by distinct events across different sleep states. Non-rapid eye movement (NREM) sleep features slow oscillations, delta waves, thalamocortical spindles and hippocampal sharp waves-ripples, while REM sleep is dominated by hippocampal theta oscillations and ponto-geniculo-occipital (PGO) waves, or pontine waves (“P-waves”) in rodents. Even though their origin from mesopontine cholinergic and glutamatergic nuclei is kn

As the use of cannabinol, often marketed as a sleep aid, is increasing, we aimed to investigate the effect of this substance on sleep. We evaluated the effect of a low dose (1 mg/kg) of cannabinol in rats using electrocorticography and electromyography. Three groups were compared: rats that received saline, vehicle (1% Tween-80 dissolved in saline), and cannabinol dissolved in vehicle. We recorded data for 24 hours after a single injection, and for 7 days with injections taking place every day. Cannabinol decreased the percentage of time spent in non-REM sleep at different times across the day

Sleep is present throughout the animal kingdom, but its function remains to be fully determined. Rapid eye movement sleep (REM) is characterised by muscle atonia, heightened theta oscillations, and the occurrence of ponto-geniculo-occipital (PGO) waves or P-waves. The pedunculopontine and laterodorsal tegmental nuclei (PPT/LDT) have been implicated in REM sleep generation, and their cholinergic neuronal activity was specifically associated with P-waves. However, the precise role of pontine cholinergic neurons in REM sleep remains elusive, particularly their impact on sleep architecture and P-w

…a strong link between ELS and poor sleep quality. Poor sleep correlates with increased risk of psychiatric disorders such as anxiety and vulnerability to stress. In this study, we investigated ELS effects on sleep architecture and spindle activity in mice. Two groups were used: ELS group experienced maternal separation for 3 hours daily from postnatal day 1-14, and a stress-naive control group. At the 8 weeks age, EEG and EMG electrodes were implanted for sleep recording. While wake and NREM sle

Mammalian sleep consists of two states: rapid-eye-movement (REM) sleep and non-REM (NREM) sleep. REM sleep is characterized by rapid eye movements, loss of muscle tone, and hippocampal theta waves. Recent studies have indicated that reduction of REM sleep is associated with an increased risk of dementia and all-cause mortality. While enhancing REM sleep may offer health benefits, the mechanisms and physiological roles of REM sleep remain incompletely understood. Previous studies have shown that the dorsal pons plays a crucial role in the regulation of REM sleep. However, little is known about

Sleep is ubiquitous in the animal kingdom, yet our understanding of its possible functions, its control and evolution, remains rudimentary. Two main sleep states have traditionally been distinguished in mammals ­– rapid-eye-movement (REM, also paradoxical or “dream sleep”) and slow-wave (SW, also non-REM) sleep – but biphasic sleep is widespread, also exists in birds and non-avian reptiles, suggesting a possibly common origin. Studying sleep in the Australian dragon Pogona vitticeps, we have previously described a reptilian homologue of the mammalian claustrum and its role in generating activi

…of the population without effective remedies. To address this issue, innovative strategies are urgently needed. Psilocybin, a non-selective 5-HT2AR agonist, has been found to alleviate depressive mood in individuals with treatment resistant depression (Carhart-Harris et al., 2017) Ketamine exhibits robust and enduring antidepressant properties both in patients and preclinical models. (Krystal et al., 2013). Sleep patterns are often affected by depressive disorders, making wireless EEG a valuable too

…of the population without effective remedies. To address this issue, innovative strategies are urgently needed. Psilocybin, a non-selective 5-HT2AR agonist, has been found to alleviate depressive mood in individuals with treatment resistant depression (Carhart-Harris et al., 2017) Ketamine exhibits robust and enduring antidepressant properties both in patients and preclinical models. (Krystal et al., 2013). Sleep patterns are often affected by depressive disorders, making wireless EEG a valuable

Aims: Compared with non-rapid eye movement (NREM) sleep, rapid eye movement (REM) sleep is characterized by low-voltage and fast electroencephalographic activity, loss of muscle tone, or intermittent muscle twitches. Waking up from REM sleep is necessary for staying alert in animals, yet it is not well known about the mechanism of the transitional signature of REM sleep. Methods: Neuronal activities of the rostromedial tegmental nucleus (RMTg), a structure in the midbrain that is primarily composed of GABAergic neurons, were manipulated using optogenetics. Electroencephalogram and electromyog

Non-motor symptoms, such as sleep problems, often precede motor symptoms in patients with Parkinson’s Disease (PD). Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is used to control motor fluctuations of PD and there is increasing evidence that STN-DBS improves patients’ subjective sleep quality. However, how and if the STN regulates the sleep-wake cycle is unknown. We recorded activity of Vglut2-neurons in the STN during mice’s inactive period (lights on) and found peak calcium signals increased when mice transitioned from NREM to wake (p<0.05) and from NREM to REM (p<0.0

Sleep is a critical factor that affects overall health, and humans typically spend one-third of their lives sleeping. Sleep consists of two states: rapid eye movement (REM) sleep and non-REM (NREM) sleep. The brainstem pontine tegmental area contains neurons that either positively or negatively regulate REM sleep (Vanni-Mercier et al., 1989; Lu et al., 2006; Hayashi et al., 2015; Kashiwagi et al., 2020). Additionally, some neurons in this area regulate urination (Hou et al., 2016; Keller et al., 2018) and fear (Yang et al., 2016). Thus, the pontine tegmental area consists of multiple subpopula

This study aims to elucidate the specific role of Rapid Eye Movement (REM) sleep, particularly its micro-architecture, in memory consolidation. While the importance of sleep for memory consolidation is well established, the focus has traditionally been on Non-Rapid Eye Movement (NREM) sleep. The distinct roles and interactions of the phasic and tonic substates of REM sleep in memory processes are less appreciated and are the focus of our current investigation. We employed a novel behavioral task, the Object Space Task (OST), to probe the neural underpinnings of simple and complex memory consol

Sleep quantity and quality change dramatically across the lifespan of altricial mammals born with immature brains such as humans and rodents (Logan 2019, Cirelli 2020, Blumberg 2005, Blumberg 2014). Despite a crucial role for healthy development, we still know quite little about developmental sleep – especially when it comes to architecture and oscillatory dynamics, or to the emergence of global inter-regional brain cross-communication. Current methods to analyse immature sleep fail to provide the resolution needed to characterise its longitudinal microstructure. We designed light-weighted chr

The synchronization of the phase of neuronal oscillations and the correlated fluctuations in the envelopes of neuronal signals are two prominent coupling modes that govern the brain dynamics. They mediate in an efficient and selective manner the communication in networks of cortical and subcortical areas to facilitate sensory processing, behavior, and perception. However, it is not clear yet if and how these two types of intrinsic coupling modes (ICMs) interact with each other. Here we investigate the relation between both coupling modes across different brain states. In accordance with our pr

…to precisely detect Wake, non-REM and REM sleep epochs. We characterized different respiratory cycle features between vigilance states and uncovered unexpected breathing dynamics at transitions between them. To show h

Sleep’s ubiquitous presence across the animal kingdom underscores its crucial role in an organism’s cognitive, emotional, and physiological function. In mammals, sleep is subdivided into two distinct substates: Rapid Eye Movement (REM) sleep and Non-rapid Eye Movement (NREM) sleep. NREM sleep is marked by synchronized brain activity and muscle tone loss, while REM sleep is characterized by desynchronized brain activity, muscle atonia, and bursts of eye movements. Nevertheless, the definition of sleep varies across species making the evolutionary origin of distinct sleep states unclear. In orga

…at the whole-brain level during sleep in humans, where the need fo

…diverse brain functions, such as sleep and metabolism, with their wide expression throughout the brain. Previous in vitro studies have found that Ox2R works in both Gq and Gi-coupled signaling pathways, indicating excitatory and inhibitory functions respectively. In vivo studies, however, the inhibitory role has yet to be discerned, whereas the excitatory function has been elucidated in numerous reports. Consequently, Ox2R is predominantly recognized for eliciting only excitatory signals i

…in various brain functions, such as sleep and memory. Across the sleep-wake cycle, astrocytic intracellular Ca2+ levels fluctuate, with distinct changes occurring across different brain regions. While the pons is highly involved in regulating rapid eye movement (REM) sleep, pontine astrocytes exhibit reduced Ca2+ signals upon REM sleep induction. However, the contribution of pontine astrocytes to REM sleep regulation remains unclear. In this project, we investigated if manipul

The sleep cycle alternates between REM (rapid eye movement) and NREM (non-rapid movement) sleep, which is a highly characteristic feature of sleep. However, the mechanisms by which this cycle is generated are totally unknown. We found that a periodic transient increase of dopamine (DA) level in the basolateral amygdala (BLA) during non-rapid eye movement (NREM) sleep terminates NREM sleep and initiates REM sleep. DA acts on dopamine receptor D2 (Drd2)-expressing neurons in the BLA to induce a transition from NREM to REM sleep. This mechanism also plays a role in cataplectic attack, which is a

REM sleep has been hypothesized to promote emotional resilience, but no neuronal circuitsmediating this have been identified. We find that in mice, somatostatin (Som) neurons in theentopeduncular nucleus (EPSom)/internal globus pallidus are predominantly active during REMsleep. This unique REM activity is necessary and sufficient for maintaining normal REM sleep.Inhibiting or exciting EPSom neurons reduced or increased REM sleep duration, respectively.Activation of the sole downstream target of EPSom neurons, Vglut2 cells in the lateral habenula(LHb), increased sleep via the ventral tegmental

…calcium activity in regulation of sleep depth and state transitions (Bojarskaite et al., 2020, Nat Comms; Vaidyanathan et al., 2021, Nat Comms). However, astrocytic activity is highly heterogeneous across brain regions, and it is unclear if astrocytes mediate sleep transitions in a brain region specific manner. A region of utmost interest to investigate astrocytic activity during sleep is the hippocampus, which not only display high astrocytic heterogeneity (Viana et al., 2023, Glia), but also shows sleep-specific pat

The sleep stage in mammals consists of rapid eye movement (REM) sleep and non-REM (NREM) sleep. Each sleep stage has its own electrophysiological characteristics. For example, REM sleep is characterized by ponto-geniculo-occipital (PGO) waves in the brainstem and theta waves in the hippocampus, and NREM sleep by sharp wave-ripples (SWRs) in the hippocampus. These are thought to be important for memory processing. To date, however, their contributions to memory have been studied independently, and no studies have addressed the relationship between hippocampal neural activities and PGO waves. PG