Occipital Lobe Movement During Rem Sleep: What's Happening?

The occipital lobe is one of the four major lobes of the brain in the cerebral cortex and is located at the back of the skull. The lobe is associated with vision and contains the visual cortex, which receives and processes visual information from the eyes.

REM sleep is one of the two main phases of sleep, the other being non-rapid eye movement (NREM) sleep. REM sleep is characterised by rapid eye movements, low muscle tone and fast, desynchronised rhythms in the cortical electroencephalogram (EEG). It is also known as paradoxical sleep or active sleep because the EEG of REM sleep is similar to the activated EEG of wakefulness.

REM sleep is associated with distinct global cortical dynamics and is controlled by the occipital cortex. During REM sleep, the occipital cortex is highly active and exhibits a unique pattern of activity. This activity is thought to be related to dream-related brain activity and visual-like processing.

PGO waves, or ponto-geniculo-occipital waves, are distinctive waveforms of propagating activity between the pons, lateral geniculate nucleus and occipital lobe. They are phasic field potentials that can be recorded during and immediately before REM sleep. PGO waves are thought to be intricately involved with eye movement during both wake and sleep cycles in many different animals.

REM sleep behaviour disorder (RBD) is a type of parasomnia that occurs during REM sleep and is characterised by vivid dreams and motor behaviours.

REM sleep is associated with distinct global cortical dynamics and is controlled by the occipital cortex

Rapid Eye Movement (REM) sleep is a sleep stage characterised by rapid eye movements, muscle atonia, and vivid dreams. REM sleep is associated with distinct global cortical dynamics and is controlled by the occipital cortex. The occipital lobe is located at the back of the brain and is primarily responsible for processing visual information. During REM sleep, the occipital cortex exhibits unique patterns of neural activity that distinguish it from other sleep stages and play a crucial role in regulating sleep states.

REM Sleep and the Occipital Cortex

Recent studies have revealed that the occipital cortex plays a crucial role in controlling REM sleep. Using advanced imaging techniques, such as calcium imaging and optogenetics, researchers have found that the occipital cortex exhibits distinct patterns of neural activity during REM sleep. Specifically, elevated activation in the occipital cortical regions, including the retrosplenial cortex and visual areas, becomes dominant during REM sleep. This activation is associated with transitions to REM sleep and promotes the switching between sleep states.

Distinct Global Cortical Dynamics

The cerebral cortex exhibits spontaneous activity during sleep, and REM sleep is characterised by distinct global cortical dynamics. Calcium imaging studies in mice have revealed that the cortex-wide calcium activity in the occipital cortex is significantly elevated during REM sleep. This elevated activity is associated with PGO (ponto-geniculo-occipital) wave-like activity, which is believed to play a role in sleep state switching.

Role of the Occipital Cortex in Sleep State Switching

The occipital cortex has been found to play an active role in controlling sleep states and promoting the transition from non-REM (NREM) sleep to REM sleep. Optogenetic inhibition of occipital activity has been shown to suppress the transition from NREM to REM sleep and promote deep sleep. Conversely, optogenetic activation of the occipital cortex has been found to increase the likelihood of transitioning from NREM to REM sleep. These findings suggest that the occipital cortex plays a crucial role in regulating sleep states and that its activity is associated with distinct global cortical dynamics during REM sleep.

In conclusion, REM sleep is associated with distinct global cortical dynamics, and the occipital cortex plays a crucial role in controlling sleep states and the transition between NREM and REM sleep. The elevated activation in the occipital cortex during REM sleep is associated with PGO wave-like activity and contributes to the unique characteristics of this sleep stage. Further research is needed to fully understand the complex dynamics of the occipital cortex during REM sleep and its role in sleep regulation.

PGO waves are distinctive waveforms of propagating activity between the pons, lateral geniculate nucleus, and occipital lobe

Ponto-geniculo-occipital (PGO) waves are distinctive waveforms of propagating activity between the pons, lateral geniculate nucleus, and occipital lobe. They are phasic field potentials that can be recorded from any of these three structures during and immediately before REM sleep. The waves begin as electrical pulses from the pons, then move to the lateral geniculate nucleus residing in the thalamus, and end in the primary visual cortex of the occipital lobe.

PGO waves are thought to be intricately involved with eye movement during both sleep and wake cycles in many different animals. They are also an integral part of REM sleep, with the density of the PGO waves coinciding with the amount of eye movement measured in REM sleep.

REM sleep is characterised by low-amplitude synchronisation of fast oscillations in the cortical EEG

Rapid Eye Movement (REM) sleep is a unique phase of sleep in mammals and birds, characterised by random rapid movement of the eyes, low muscle tone, and the propensity of the sleeper to dream vividly. The core body and brain temperatures increase during REM sleep, and skin temperature decreases to its lowest values.

REM sleep is called "paradoxical sleep" due to its similarities to wakefulness. Although the body is paralysed, the brain acts as if it is awake, with cerebral neurons firing with the same intensity as in wakefulness.

REM sleep is usually considered a unitary state in neuroscientific research; however, it is composed of two different microstates: phasic and tonic REM. These differ in awakening thresholds, sensory processing, and cortical oscillations.

REM Sleep and the Occipital Lobe

REM sleep is associated with distinct global cortical dynamics and is controlled by the occipital cortex. The cerebral cortex is spontaneously active during sleep, but it is unclear how this global cortical activity is spatiotemporally organised, and whether such activity not only reflects sleep states but also contributes to sleep state switching.

In a study using mesoscale Ca2+ imaging in mice, distinct sleep stage-dependent spatiotemporal patterns of global cortical activity were found, and modulation of such patterns could regulate sleep state switching. In particular, elevated activation in the occipital cortical regions (including the retrosplenial cortex and visual areas) became dominant during REM sleep. Furthermore, such pontogeniculooccipital (PGO) wave-like activity was associated with transitions to REM sleep, and optogenetic inhibition of occipital activity strongly promoted deep sleep by suppressing the NREM-to-REM transition.

REM Sleep and Cortical Synchronisation

REM sleep is a complex and heterogeneous state, with phasic and tonic periods that are markedly different neural states. Considering the microarchitecture of REM sleep may provide new insights into the mechanisms and functions of REM sleep in health and disease.

REM sleep is associated with an intense neuronal activity, similar to waking levels

Rapid Eye Movement (REM) sleep is a sleep stage characterised by rapid eye movements, muscle atonia, and vivid dreams. REM sleep is associated with intense neuronal activity, similar to waking levels. This neuronal activity is believed to play a crucial role in memory consolidation and emotional processing.

Neuronal Activity During REM Sleep

REM sleep is associated with distinct global cortical dynamics and is controlled by the occipital cortex. The cerebral cortex remains active during sleep, and its activity is organised into specific patterns depending on the sleep-wake stage. During REM sleep, there is elevated activation in the occipital cortical regions, including the retrosplenial cortex and visual areas. This activation is associated with transitions to REM sleep and is believed to play a role in sleep state switching.

Single-unit recordings and intracranial electroencephalography have revealed that neuronal activity in the medial temporal lobe (MTL) is robustly modulated by REMs, with a reduction in firing rate before REM onset and a subsequent increase in firing rate. This bi-phasic pattern of neuronal activity is more prevalent in the MTL compared to frontal regions and is reminiscent of visual-like processing during wakefulness.

Furthermore, the selectivity of individual neurons in the MTL is correlated with their response latency, with neurons activated after a small number of images or REMs exhibiting delayed increases in firing rates. The phase of theta oscillations is also reset following REMs, with similar dynamics observed during wakefulness and controlled visual stimulation.

The Role of PGO Waves

PGO waves, or ponto-geniculo-occipital waves, are distinctive waveforms that propagate between the pons, lateral geniculate nucleus, and occipital lobe. These waves are associated with eye movements during both wakefulness and REM sleep and are believed to play a role in the generation of REM sleep. PGO waves have been studied primarily in animal models, but they have also been observed in humans.

REM sleep is associated with intense neuronal activity in the occipital lobe and other brain regions. This neuronal activity exhibits distinct patterns and is believed to play a role in memory consolidation, emotional processing, and sleep state regulation. The specific functions and mechanisms underlying neuronal activity during REM sleep remain to be fully elucidated and require further investigation.

REM sleep is a paradoxical sleep because the EEG during REM sleep is similar to the activated EEG of waking or of stage N1

Rapid Eye Movement (REM) sleep is a unique sleep phase in mammals and birds, characterised by random rapid eye movement, low muscle tone, and the tendency to dream vividly. During REM sleep, the brain acts similarly to its wakeful state, with cerebral neurons firing with the same intensity. This is why REM sleep is also known as paradoxical sleep.

REM sleep is associated with low-amplitude, fast oscillations in the cortical electroencephalogram (EEG), also called activated EEG. The EEG during REM sleep is similar to the activated EEG of waking or of stage N1 sleep. The activated EEG is characterised by fast, low-amplitude EEG oscillations.

During REM sleep, the brain exhibits intense neuronal activity, similar to waking levels. Brain glucose metabolism and oxygen utilisation are elevated during REM sleep and reach levels comparable to wakefulness. However, the spatial distribution of brain activity during REM sleep and wakefulness differs significantly.

REM sleep is associated with sympathetic activation and is referred to as paradoxical sleep. Although REM sleep is predominantly a parasympathetic state, it is marked by significant fluctuations in autonomic nervous system activity.

REM sleep can be divided into two distinct patterns: tonic and phasic. Tonic REM is a persistent state throughout the sleep stage, while the phasic REM component is intermittent and superimposed. It is characterised by bursts of sympathetic activity, rapid eye movements, and brief irregular muscle twitches superimposed on muscle atonia.

The transition from non-REM (NREM) sleep to REM sleep is marked by elevated activation in the occipital cortical regions, including the retrosplenial cortex and visual areas. This activation is associated with transitions to REM sleep and is essential for promoting the transition from NREM to REM sleep.

In summary, REM sleep is considered paradoxical because the EEG during this sleep stage is similar to the activated EEG of waking or stage N1 sleep, exhibiting fast, low-amplitude oscillations and intense neuronal activity.

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