Orexin/Hypocretin: A Neuropeptide at the Interface of Sleep, Energy
... 2005; Yoshida et al., 2006). These studies showed that
orexin neurons are innervated by the lateral parabrachial nucleus, ventrolateral preoptic nucleus (VLPO),
medial and lateral preoptic areas, basal forebrain (BF),
posterior/dorsomedial hypothalamus, VTA, and median
raphe nuclei. Many upstream ne ...
to eat or to sleep? orexin in the regulation of feeding and wakefulness
... The regulation of sleep-wakefulness cycling within the context of circadian and
environmental influences is critical for the efficient maintenance of energy homeostasis. In mammals, the sleep-wakefulness cycle can be divided into periods of
waking, non-rapid-eye-movement (non-REM), and rapid-eye-mov ...
Chemical Transmitters and Modulation of Sleep
... found that across the BF and the adjacent preoptic area, more cells including cholinergie
neurons were active during waking than during sleep and thus contribute to generating a
waking state. On the other hand, the proportion of c-Fos expressing neurons that were
GABAergic was higher during sleep re ...
The rat ponto-medullary network responsible for paradoxical
... In the middle of the last century, a series of historical observations lead to the discovery of a
vigilance state in humans and other mammals paradoxically characterized by cortical activation and
rapid eye movements, but associated with a complete disappearance of the muscle tone (Aserinsky
and Kle ...
32 - Open-mind.net
... where sensory input by constraining the
intrinsic functional states specifies, rather
than informs, the brain of those properties
of external reality that are important for
survival. […] That consciousness is generated intrinsically is not difficult to understand when one considers the completeness
THE REGULATION OF SLEEP AND WAKEFULNESS BY THE
... neurons of the pedunculopontine tegmental nucleus (PPN) and the laterodorsal tegmental nucleus
(LDT) play a pivotal role in the regulation of REM sleep and wakefulness. These areas are also
strongly innervated by orexin neurons7,8). Microinjection of orexin-A into the LDT increases awake
time and de ...
Reverse pharmacology of orexin
... these cells during wakefulness. Orexin neurons might
activate another type of cholinergic neurons in the PPT
and LDT, which are active in wakefulness as well as the
REM-sleep period. Recent work also shows that orexin
inhibits cholinergic neurons in the PPT via activation of
GABAergic local interneu ...
Circadian and histaminergic regulation of the sleep
... During 6-hours of sleep deprivation, the histamine release was constantly upregulated and
comparable to its level during wakefulness, whereas when the sleep deprivation ceased, the
release of histamine immediately dropped to the baseline level. Constant administration of
histamine into the basal for ...
Effect of Sleep on Vigilance, Short-Term Memory
... Although there are many debates about the need for sleep in the scientific
community, no one really knows why humans sleep. Scholars have proposed a number of
hypotheses in an attempt to explain the function of sleep. One theory is the restorative
theory of sleep, which proposes that the body repair ...
Analysis of sleep spindles and model of their generation
... Sleep spindles are present in the sleep EEG from infancy throughout life until old age. Their morphology changes with age reflecting changes in brain
connectivity. Spindles develop in humans at 6 weeks after birth at first at
low amplitude, gradually increasing in amplitude but especially in duratio ...
Genetic Ablation of Orexin Neurons in Mice Results in Narcolepsy
... the orexin system in the human sleep disorder narcolepsy. Narcolepsy is the only neurological disorder characterized by a primary disorganization of sleep and
wakefulness. Patients with narcolepsy suffer from excessive daytime sleepiness, cataplexy (a sudden weakening of posture muscle tone usually ...
Serotonergic Integration of Circadian Clock and Ultradian Sleep
... Average of normalized MUA rhythms in the SCN (mean ⫾ SD, n ⫽ 6). The MUA at each time point was normalized by the total number of spikes before or after TSOI injection (2.5 days), and the MUAs
were then averaged. Black/white bars, 12:12 h dark/light phase. B includes data from A (under light: dark c ...
C-fos Expression in the Pons and Medulla of the Cat during
... horseradish peroxidase complex at a I: 100 dilution in TBS. The slides were then rinsed in TBS and
peroxidase activity was visualized using equal parts 0.02% hydrogen
peroxidase and 0. I % diaminobenzidine
tetrahydrochloride (Sigma) in
TBS (pH 7.6) for 8-l 5 min. After a final three rinses (I 5 min ...
... sleep time and it is mainly characterized by fast movements of the eyes, desynchronized
high-frequency EEG activity, muscle atonia, PGO waves (recorded from the pons, the
geniculatum, and the occipital cortex), and theta frequency (4-10 Hz) oscillation in the
hippocampal formation. Brain activity la ...
Changes in Monoamine Release in the Ventral Horn and
... and a reduction of muscle tone in the respiratory related musculature occur in rapid eye movement (REM) sleep. Previous
studies have emphasized the role of glycine in generating these
changes. Because the activity of norepinephrine- and
serotonin-containing neurons is known to decrease in REM
Modulation of Cortical Activation and Behavioral Arousal by
... FIGURE 1. Cholinergic, orexinergic, and other neurons involved in sleep–wake state control. Sagittal schematic view
of the rat brain depicting neurons with their chemical neurotransmitters and pathways by which they influence cortical
activity or behavior across the sleep–wake cycle. Wake (W) is cha ...
04 narc John neuron
... Noradrenergic, serotonergic, and histaminergic neurons are continuously active during waking, reduce
discharge during NREM sleep, and cease discharge
during REM sleep. Cataplexy, a symptom associated
with narcolepsy, is a waking state in which muscle
tone is lost, as it is in REM sleep, while enviro ...
Functional Neuroimaging Insights into the Physiology of Human Sleep
... a drop of brain activity during NREM sleep when compared
to wakefulness.20-23,31 Quantitatively, this decrease has been estimated at around 40% during slow wave sleep (SWS; stages
3-4 NREM) compared to wakefulness.24 Regionally, reductions
of brain activity were located in subcortical (brainstem, th ...
Behavioral Response and Transmitter Release During Atonia
... remaining 5 cases in the medial medulla elicited contralateral
inhibition with no change in ipsilateral muscle tone.
In contrast to their responses in waking, when stimulation with
the same parameters was applied during SWS, bilateral inhibition
without after-facilitation occurred in all cases (Fig. ...
A Critical Period of Sleep for Development of Courtship Circuitry and
... sleep lost during the night in young and mature
flies, using two forms of deprivation (mechanical
and temperature). Mature flies exhibited large
amounts of sleep loss, particularly with mechanical deprivation, but young flies were resistant
(Fig. 1D). Increasing the intensity of mechanical
Hippocampal CA1 pyramidal cells form functionally
... oscillation (P < 0.0001, t test; Fig. 3). Together, these findings indicate
that the entorhinal input can differentially activate superficial and
deep subgroups of CA1 pyramidal cells during slow-wave sleep.
We also investigated the relationship between sharp wave–ripple
patterns28 and the depth of ...
LESSON 4.3 WORKBOOK What makes us go to sleep, and what
... So what causes narcolepsy?
Narcolepsy is a relatively uncommon condition — only one case per 2,500 people — but it is a great
example of a defect in the flip-flop switch that controls the transition between wakefulness and sleep,
particularly REM sleep.
Narcoleptics have sleep attacks during the day ...
Memory Processing in Relation to Sleep
... experience was shown to influence the content of hypnagogic hallucinations53 and of dreams collected on awakening from sleep stages54,55 on the postexposure night,
although delayed incorporations of up to weeks have also
been reported often.55
Noninvasive neuroimaging studies, especially using posit ...
A role for sleep in brain plasticity
... remodelling elicited by MD. Another study has
shown that non-REM sleep electrical activity itself
underwent changes as a consequence of waking
experience during a late critical period (P30–60) in
cats and mice : dark-rearing induced during
sleep a huge and reversible decrement of delta
What Keeps Us Awake: the Neuropharmacology of Stimulants and
... in the brain17 and their interaction with autonomic, neuroendocrine, and neuroregulatory systems18-25 strongly suggest they
act as neuromodulators in a wide array of neural circuitry. They
also have been implicated in the modulation of noradrenergic,20,26-28 cholinergic,29 serotonergic,30,31 histami ...
Rapid eye movement sleep
Rapid eye movement sleep (REM sleep, REMS) is a unique phase of mammalian sleep characterized by random movement of the eyes, low muscle tone throughout the body, and the propensity of the sleeper to dream vividly. This phase is also known as paradoxical sleep (PS) and sometimes desynchronized sleep because of physiological similarities to waking states, including rapid, low-voltage desynchronized brain waves. Electrical and chemical activity regulating this phase seems to originate in the brain stem and is characterized most notably by an abundance of the neurotransmitter acetylcholine, combined with a nearly complete absence of monoamine neurotransmitters histamine, serotonin, and norepinepherine. The cortical and thalamic neurons of the waking or paradoxically sleeping brain are more depolarized—i.e., can ""fire"" more readily—than in the deeply sleeping brain. The right and left hemispheres of the brain are more coherent in REM sleep, especially during lucid dreams.REM sleep is punctuated and immediately preceded by PGO (ponto-geniculo-occipital waves) waves, bursts of electrical activity originating in the brain stem. These waves occur in clusters about every 6 seconds for 1–2 minutes during the transition from deep to paradoxical sleep. They exhibit their highest amplitude upon moving into the visual cortex and are a cause of the ""rapid eye movements"" in paradoxical sleep.Brain energy use in REM sleep, as measured by oxygen and glucose metabolism, equals or exceeds energy use in waking. The rate in non-REM sleep is 11–40% lower.