Local sleep homeostasis in the avian brain: convergence of sleep function in mammals and birds?

The function of the brain activity that defines slow wave sleep (SWS) and rapid eye movement (REM) sleep in mammals is unknown. During SWS, the level of electroencephalogram slow wave activity (SWA or 0.5–4.5 Hz power density) increases and decreases as a function of prior time spent awake and asleep, respectively. Such dynamics occur in response to waking brain use, as SWA increases locally in brain regions used more extensively during prior wakefulness. Thus, SWA is thought to reflect homeostatically regulated processes potentially tied to maintaining optimal brain functioning. Interestingly, birds also engage in SWS and REM sleep, a similarity that arose via convergent evolution, as sleeping reptiles and amphibians do not show similar brain activity. Although birds deprived of sleep show global increases in SWA during subsequent sleep, it is unclear whether avian sleep is likewise regulated locally. Here, we provide, to our knowledge, the first electrophysiological evidence for local sleep homeostasis in the avian brain. After staying awake watching David Attenborough's The Life of Birds with only one eye, SWA and the slope of slow waves (a purported marker of synaptic strength) increased only in the hyperpallium—a primary visual processing region—neurologically connected to the stimulated eye. Asymmetries were specific to the hyperpallium, as the non-visual mesopallium showed a symmetric increase in SWA and wave slope. Thus, hypotheses for the function of mammalian SWS that rely on local sleep homeostasis may apply also to birds.

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0078 Influence of Light on Brain Activity Upon Waking From Slow Wave Sleep

SLEEP ◽

10.1093/sleep/zsaa056.076 ◽

2020 ◽

Vol 43 (Supplement_1) ◽

pp. A31-A32 ◽

Cited By ~ 1

Author(s):

E E Flynn-Evans ◽

C J Hilditch ◽

R Chachad ◽

K Bansal ◽

L R Wong ◽

...

Keyword(s):

Slow Wave ◽

Slow Wave Sleep ◽

Brain Activity ◽

Effective Connectivity ◽

Red Light ◽

Spectral Composition ◽

Brain Regions ◽

Graphical Analysis ◽

Sleep Inertia ◽

Temporal Persistence

Abstract Introduction Waking from sleep is associated with reduced alertness due to sleep inertia. Light acutely improves alertness during sleep deprivation. In this study we assessed the influence of light on brain activity and connectivity after waking from slow wave sleep (SWS). Methods Twelve participants kept an actigraphy-confirmed stable sleep schedule with 8.5 hours for five nights and five hours for one night prior to an overnight laboratory visit. Participants completed two three-minute Karolinska Drowsiness Tests (KDT) before going to bed at their habitual bedtime. They were monitored continuously using high-density EEG (32-channel; Brain Products GmbH). Participants were woken twice and exposed to red light (0.01 melanopic-lux; control) or blue-enriched light (63.62 melanopic-lux) for one hour, in a randomized order, following at least five minutes of SWS. EEG artifact were removed algorithmically and the spectral composition of each electrode (i.e., fast fourier transform, FFT) and effective connectivity (i.e., partial directed coherence, PDC) between each electrode were estimated. A graphical analysis was conducted to extract features relevant to the facilitation of efficient communication between electrodes. All data were averaged within frequency bins of interest that correspond to delta (1-3Hz), theta (4-7Hz), alpha (8-12Hz), and beta (13-25Hz) bands and expressed relative to the pre-sleep baseline. Results Compared to the pre-sleep baseline, participants exposed to blue-enriched light experienced reduced theta and alpha activity; however, these results were not significantly different from the control. In contrast, the communication of frontal electrodes significantly increased across all frequency bands compared to the control, and this effect was most prominent in the alpha (t(11)=3.80, p=.005) and beta bands (t(11)=3.92, p=.004). Conclusion Exposure to blue-enriched light immediately after waking from SWS may accelerate the process of waking and help to improve alertness by facilitating communication between brain regions. Future analyses will explore the temporal persistence and granularity of the communicative properties associated with this response. Support Naval Postgraduate School Grant. NASA Airspace Operations and Safety Program, System-Wide Safety Project.

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Reward biases spontaneous neural reactivation during sleep

Nature Communications ◽

10.1038/s41467-021-24357-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Virginie Sterpenich ◽

Mojca K. M. van Schie ◽

Maximilien Catsiyannis ◽

Avinash Ramyead ◽

Stephen Perrig ◽

...

Keyword(s):

Functional Mri ◽

Slow Wave ◽

Slow Wave Sleep ◽

Life Experiences ◽

Brain Activity ◽

Memory Performance ◽

Neural Mechanism ◽

Brain Regions ◽

Evolutionary Perspective ◽

Neural Representations

AbstractSleep favors the reactivation and consolidation of newly acquired memories. Yet, how our brain selects the noteworthy information to be reprocessed during sleep remains largely unknown. From an evolutionary perspective, individuals must retain information that promotes survival, such as avoiding dangers, finding food, or obtaining praise or money. Here, we test whether neural representations of rewarded (compared to non-rewarded) events have priority for reactivation during sleep. Using functional MRI and a brain decoding approach, we show that patterns of brain activity observed during waking behavior spontaneously reemerge during slow-wave sleep. Critically, we report a privileged reactivation of neural patterns previously associated with a rewarded task (i.e., winning at a complex game). Moreover, during sleep, activity in task-related brain regions correlates with better subsequent memory performance. Our study uncovers a neural mechanism whereby rewarded life experiences are preferentially replayed and consolidated while we sleep.

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Neostriatal administration of somatostatin: differential effect of small and large doses on behavior and motor control

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y77-034 ◽

1977 ◽

Vol 55 (2) ◽

pp. 234-242 ◽

Cited By ~ 49

Author(s):

M. Rezek ◽

V. Havlicek ◽

L. Leybin ◽

C. Pinsky ◽

E. A. Kroeger ◽

...

Keyword(s):

Motor Control ◽

Eye Movements ◽

Slow Wave ◽

Rem Sleep ◽

Differential Effect ◽

Slow Wave Sleep ◽

Small Doses ◽

Freely Moving ◽

Behavioral Excitation ◽

Higher Doses

The administration of small doses of somatostatin (SRIF) (0.01 and 0.1 μg) into the neostriatal complex of unrestrained, freely moving rats induced general behavioral excitation associated with a variety of stereotyped movements, tremors, and a reduction of rapid eye movements (REM) and deep slow wave sleep (SWS). In contrast, the higher doses of SRIF (1.0 and 10.0 μg) caused movements to be uncoordinated and frequently induced more severe difficulties in motor control such as contralateral hemiplegia-in-extension which restricted or completely prevented the expression of normal behavioral patterns. As a result, the animals appeared drowsy and inhibited. Analysis of the sleep-waking cycle revealed prolonged periods of a shallow SWS while REM sleep and deep SWS were markedly reduced; electroencephalogram recordings revealed periods of dissociation from behavior. The administration of endocrinologically inactive as well as the active analogues of SRIF failed to induce effects comparable with those observed after the administration of the same dose of the native hormone (10.0 μg).

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Selection of stimulus parameters for enhancing slow wave sleep events with a Neural-field theory thalamocortical computational model

10.1101/2021.02.03.429528 ◽

2021 ◽

Author(s):

Felipe A. Torres ◽

Patricio Orio ◽

María-José Escobar

Keyword(s):

Computational Model ◽

Slow Wave ◽

Memory Consolidation ◽

Closed Loop ◽

Slow Wave Sleep ◽

Brain Activity ◽

Sensory Stimulation ◽

Sleep Spindles ◽

Slow Oscillations ◽

Closed Loop Stimulation

AbstractSlow-wave sleep cortical brain activity, conformed by slow-oscillations and sleep spindles, plays a key role in memory consolidation. The increase of the power of the slow-wave events, obtained by auditory sensory stimulation, positively correlates to memory consolidation performance. However, little is known about the experimental protocol maximizing this effect, which could be induced by the power of slow-oscillation, the number of sleep spindles, or the timing of both events’ co-occurrence. Using a mean-field model of thalamocortical activity, we studied the effect of several stimulation protocols, varying the pulse shape, duration, amplitude, and frequency, as well as a target-phase using a closed-loop approach. We evaluated the effect of these parameters on slow-oscillations (SO) and sleep-spindles (SP), considering: (i) the power at the frequency bands of interest, (ii) the number of SO and SP, (iii) co-occurrences between SO and SP, and (iv) synchronization of SP with the up-peak of the SO. The first three targets are maximized using a decreasing ramp pulse with a pulse duration of 50 ms. Also, we observed a reduction in the number of SO when increasing the stimulus energy by rising its amplitude. To assess the target-phase parameter, we applied closed-loop stimulation at 0º, 45º, and 90º of the phase of the narrow-band filtered ongoing activity, at 0.85 Hz as central frequency. The 0º stimulation produces better results in the power and number of SO and SP than the rhythmic or aleatory stimulation. On the other hand, stimulating at 45º or 90º change the timing distribution of spindles centers but with fewer co-occurrences than rhythmic and 0º phase. Finally, we propose the application of closed-loop stimulation at the rising zero-cross point using pulses with a decreasing ramp shape and 50 ms of duration for future experimental work.Author summaryDuring the non-REM (NREM) phase of sleep, events that are known as slow oscillations (SO) and spindles (SP) can be detected by EEG. These events have been associated with the consolidation of declarative memories and learning. Thus, there is an ongoing interest in promoting them during sleep by non-invasive manipulations such as sensory stimulation. In this paper, we used a computational model of brain activity that generates SO and SP, to investigate which type of sensory stimulus –shape, amplitude, duration, periodicity– would be optimal for increasing the events’ frequency and their co-occurrence. We found that a decreasing ramp of 50 ms duration is the most effective. The effectiveness increases when the stimulus pulse is delivered in a closed-loop configuration triggering the pulse at a target phase of the ongoing SO activity. A desirable secondary effect is to promote SPs at the rising phase of the SO oscillation.

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Insights into paradoxical (REM) sleep homeostatic regulation in mice using an innovative automated sleep deprivation method

SLEEP ◽

10.1093/sleep/zsaa003 ◽

2020 ◽

Vol 43 (7) ◽

Cited By ~ 3

Author(s):

Sébastien Arthaud ◽

Paul-Antoine Libourel ◽

Pierre-Hervé Luppi ◽

Christelle Peyron

Keyword(s):

Slow Wave ◽

Rem Sleep ◽

High Efficiency ◽

Environmental Changes ◽

Slow Wave Sleep ◽

Paradoxical Sleep ◽

Corticosterone Level ◽

Plasma Corticosterone ◽

Homeostatic Regulation ◽

External Modulation

Abstract Identifying the precise neuronal networks activated during paradoxical sleep (PS, also called REM sleep) has been a challenge since its discovery. Similarly, our understanding of the homeostatic mechanisms regulating PS, whether through external modulation by circadian and ultradian drives or via intrinsic homeostatic regulation, is still limited, largely due to interfering factors rendering the investigation difficult. Indeed, none of the studies published so far were able to manipulate PS without significantly altering slow-wave sleep and/or stress level, thus introducing a potential bias in the analyses. With the aim of achieving a better understanding of PS homeostasis, we developed a new method based on automated scoring of vigilance states—using electroencephalogram and electromyogram features—and which involves closed-loop PS deprivation through the induction of cage floor movements when PS is detected. Vigilance states were analyzed during 6 and 48 h of PS deprivation as well as their following recovery periods. Using this new automated methodology, we were able to deprive mice of PS with high efficiency and specificity, for short or longer periods of time, observing no sign of stress (as evaluated by plasma corticosterone level and sleep latency) and requiring no human intervention or environmental changes. We show here that PS can be homeostatically modulated and regulated while no significant changes are induced on slow-wave sleep and wakefulness, with a PS rebound duration depending on the amount of prior PS deficit. We also show that PS interval duration is not correlated with prior PS episode duration in the context of recovery from PS deprivation.

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Each distinct type of mental state is supported by specific brain functions

Behavioral and Brain Sciences ◽

10.1017/s0140525x00434023 ◽

2000 ◽

Vol 23 (6) ◽

pp. 941-943 ◽

Cited By ~ 5

Author(s):

Claude Gottesmann

Keyword(s):

Slow Wave ◽

Mental State ◽

Rem Sleep ◽

Psychological Functioning ◽

Slow Wave Sleep ◽

Mental Content ◽

Distinct Type ◽

Inhibitory Processes ◽

Brain Functions

Reflective waking mentation is supported by cortical activating and inhibitory processes. The thought-like mental content of slow wave sleep appears with lower levels of both kinds of influence. During REM sleep, the equation: activation + disinhibition + dopamine may explain the often psychotic-like mode of psychological functioning.[Hobson et al.; Nielsen; Revonsuo; Solms; Vertes & Eastman]

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