Skip to main content Accessibility help

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
×
  1. Home
  2. Search

Refine search

Refine search

Access:
Content type:
Publication date:
Apply   From and To filters
Subject: Show more
Journals Show more
Publishers: Show more
Societies Show more
Series: Show more
Collections: Show more

Actions for selected content:

Select all | Deselect all
  • View selected items
  • Export citations
  • Download PDF (zip)
  • Save to Kindle
  • Save to Dropbox
  • Save to Google Drive

Save Search

You can save your searches here and later view and run them again in "My saved searches".

Please provide a title, maximum of 40 characters.
Cancel
×

11 results

  • Chapter 11 - Sleep Disorders and Psychiatry

  • Edited by David Kingdon, University of Southampton, Paul Rowlands, Derbyshire Healthcare NHS foundation Trust, George Stein, Emeritus of the Princess Royal University Hospital
  • Book:
    Seminars in General Adult Psychiatry
    Published online:
    04 April 2024
    Print publication:
    18 April 2024, pp 546-564

  • Summary

    Sleep is one of the great mysteries of human experience. It is a behaviour that is highly preserved throughout the animal kingdom, and it constitutes a third of our existence. It begins before birth and is with us throughout life. For a newborn baby, it is their predominant behaviour and continues to occupy a large proportion of our lives as we age. It has long been suspected that it is essential for good mental and physical health, and in the last century, there has been growing scientific evidence to confirm this suspicion. Yet, we know very little about the functions of sleep and are only just beginning to understand the mechanisms that control it. In the past, it was commonly assumed that sleep had ’a function’, but the more we have come to understand, the clearer it has become that sleep performs multiple functions. Precisely what those functions are is still uncertain, and they may change across the lifespan or possibly even vary across different species. We know that sleep is essential for life and total sleep deprivation for long enough is fatal, and the fact that we spend a third of our lives in this vulnerable state underlines how important sleep must be.

  • Is sleep in animals affected by prior waking experiences?

  • FM Langford, MS Cockram
  • Journal:
    Animal Welfare / Volume 19 / Issue 3 / August 2010
    Published online by Cambridge University Press:
    01 January 2023, pp. 215-222
    • Article
      • You have access
    • PDF
    • Export citation

  • Methods to assess changes in the mental state of animals in response to their environment can be used to provide information to enhance animal welfare. One of the most profound changes of mental state observable in mammals is the change between wakefulness and sleep. Sleeping mammals have characteristics that are similar to one another and are measurable, such as specific behaviours, changes in responsiveness to external stimuli and changes in electrophysiology and neurochemistry. Although sleep is a ubiquitous behaviour in the life of mammals, there has been relatively little research on this topic in domesticated animals. All animals are motivated to sleep and this motivation increases after a prolonged period of wakefulness. In humans, sleep can be affected by what has occurred in the prior period of wakefulness and this has also been demonstrated in some non-human mammals. An important aspect of human sleep medicine is the association between stress and subsequent sleep disturbances. Studying changes in amount, bout length, distribution or type of sleep after exposure to potentially stressful events, could help us understand how animals respond to changes in their environment. It is possible that different types of stressors could affect sleep characteristics in different ways and that monitoring and identifying these changes could be useful in providing an additional way of identifying management procedures that have the potential to affect welfare. Sleep measurement is a potentially valuable tool in studies to assess animal welfare.

  • Chapter 8 - Normal Adult EEG

  • from Part I - Basics
  • Neville M. Jadeja
  • Book:
    How to Read an EEG
    Published online:
    24 June 2021
    Print publication:
    15 July 2021, pp 53-60

  • Summary

    The normal EEG doesn’t change much during adult life, but it must be interpreted in the context of physiological states (awake, drowsy, or asleep). Normal wakefulness is characterized by a reactive posterior dominant alpha rhythm, anterior faster beta activity, eye blink, and muscle artifact. Transition to drowsiness is typically characterized by attenuation of the posterior dominant rhythm, diffuse slowing into theta range, emergence of slow lateral eye movements, and dissipation of muscle artifact. Vertex waves are the architectural feature of stage I sleep. Positive Occipital Sharp Transients of Sleep (POSTS) may also occur. Sleep spindles and K complexes are the architectural feature of stage II sleep. Mitten waves are a normal variant, while dyshormia is abnormal. Slow wave sleep is characterized by diffuse high-amplitude semi-rhythmic delta slowing. Rapid eye movement sleep is characterized by eye movement artifact and sawtooth waves.

  • Chapter 22 - Memory systems, sleep, and neuroimaging

  • from Section 4 - Sleep and memory
  • Edited by Eric Nofzinger, University of Pittsburgh, Pierre Maquet, Université de Liège, Belgium, Michael J. Thorpy
  • Book:
    Neuroimaging of Sleep and Sleep Disorders
    Published online:
    05 March 2013
    Print publication:
    07 March 2013, pp 179-186

  • Summary

    Although the neurophysiological origin of the functional magnetic resonance imaging (fMRI) blood oxygen level-dependent (BOLD) signal is still poorly understood, spontaneous fMRI signal fluctuations show consistent spatial correlations in functionally related networks. Large-scale functional brain networks as derived from fMRI time-series can be examined by graph theoretical analysis; such analysis has revealed a small-world organization of human functional brain networks during wakefulness, with high local clustering and short path length. A hierarchical cluster analysis indeed illustrated that frontoparietal clusters could be detected in wakefulness but not in deeper non-rapid eye movement (NREM) sleep stages. Functional connectivity of phasic events allows further spatial and temporal refinement of vigilance-state dependent connectivity patterns, and may be of special interest for phasic electroencephalography (EEG) events during sleep. Finally, although functional connectivity appears to overlap to a considerable extent with brain metabolism, these measures seem to represent correlated but different dimensions.

  • Chapter 21 - Neuroimaging the effects of light on non-visual brain functions

  • from Section 3 - Neuroimaging, sleep loss, and circadian misalignment
  • Edited by Eric Nofzinger, University of Pittsburgh, Pierre Maquet, Université de Liège, Belgium, Michael J. Thorpy
  • Book:
    Neuroimaging of Sleep and Sleep Disorders
    Published online:
    05 March 2013
    Print publication:
    07 March 2013, pp 171-178

  • Summary

    This chapter reviews the functional brain imaging studies, using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), that have examined neural activity patterns between non-rapid eye movement (NREM) sleep and wakefulness, and within NREM sleep in association with phasic neuronal oscillations. It explores recent fMRI data investigating the relationship between these rhythms and the processing of external stimulation during sleep. In order to further explore this relationship between external stimulation and NREM sleep phasic activity, brain responses to pure tones delivered during NREM sleep were evaluated in a recent event-related fMRI study. In the fMRI study, the relationship between auditory stimulation and slow waves was also explored. It is well known that external stimulation during NREM sleep can trigger a slow wave on electroencephalographic (EEG) recordings: such evoked slow waves, especially during stage N2, are also termed K-complexes.

  • Chapter 8 - Fundamentals of magnetoencephalography

  • from Section 1 - Introduction
  • Edited by Eric Nofzinger, University of Pittsburgh, Pierre Maquet, Université de Liège, Belgium, Michael J. Thorpy
  • Book:
    Neuroimaging of Sleep and Sleep Disorders
    Published online:
    05 March 2013
    Print publication:
    07 March 2013, pp 62-71

  • Summary

    Greater insights into the mechanisms and consequences of sleep and sleep disorders have been achieved through advances in brain imaging methods that describe various aspects of neural function. These are collectively referred to as functional neuroimaging. These include techniques such as PET, fMRI, single-photon emission computed tomography (SPECT), transcranial sonography, magnetoencephalography (MEG), low-resolution brain electromagnetic tomography (LORETA), and combined methods such as combined EEG and fMRI. Extensive applications of brain imaging have been made to help clarify the changes in regional brain function that result from perturbations in either homeostatic or circadian processes, and also have clarified the relationship between these brain changes and the behavioral consequences of these disruptions. The earliest applications of neuroimaging to the study of sleep disorders were those of functional neuroimaging methods to study the global brain states of waking, NREM, and REM sleep. Brain imaging studies have been utilized in narcolepsy and the hypersomnias.

  • Chapter 19 - Functional imaging of inter-individual differences in response to sleep deprivation

  • from Section 3 - Neuroimaging, sleep loss, and circadian misalignment
  • Edited by Eric Nofzinger, University of Pittsburgh, Pierre Maquet, Université de Liège, Belgium, Michael J. Thorpy
  • Book:
    Neuroimaging of Sleep and Sleep Disorders
    Published online:
    05 March 2013
    Print publication:
    07 March 2013, pp 154-162

  • Summary

    This chapter reports results on spontaneous brain activity during wakeful rest. It focuses on findings obtained with electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), either acquired separately or simultaneously. The chapter discusses two approaches to analyze resting state activity with fMRI, namely reverse subtraction (activity correlated with task deactivation) and independent component analysis (ICA)-based region analysis. A third way to explore resting state blood oxygen level-dependent (BOLD) activity is to add information obtained with independent recording modalities, in particular EEG. When EEG and fMRI are recorded simultaneously, fMRI activity patterns associated with EEG-defined brain states can be analyzed. Relaxed wakefulness in the EEG is characterized by alpha and beta band oscillations. A thorough analysis of EEG and fMRI patterns during wakeful rest yields a complex relationship where certain EEG patterns can be associated with different BOLD maps and vice versa.

  • Chapter 30 - Neuroimaging of Kleine–Levin syndrome

  • from Section 5 - Neuroimaging of sleep disorders
  • Edited by Eric Nofzinger, University of Pittsburgh, Pierre Maquet, Université de Liège, Belgium, Michael J. Thorpy
  • Book:
    Neuroimaging of Sleep and Sleep Disorders
    Published online:
    05 March 2013
    Print publication:
    07 March 2013, pp 240-245

  • Summary

    This chapter focuses on two recent studies capitalizing on inter-individual differences in response to increased sleep homeostasis and misalignment between the circadian signal and sleep to better characterize the brain mechanisms involved in the maintenance of wakefulness and associated cognitive processes. Extreme chronotypes are characterized by marked differences in their preferred timing for sleep and wakefulness, as well as optimal times of day to perform cognitively demanding tasks. A study detailed in the chapter used a genetic trait as a means to characterize the regulation of cognitive performance throughout a normal waking day and following total sleep deprivation. A variable-number-of-tandem-repeat (VNTR) polymorphism in the coding region of the clock gene PERIOD3 (PER3) was reported to present a weak association with chronotype. According to a recent model of cognition, the VLPFC plays a key role in higher cognitive control and is involved in complex neurobehavioral processes.

  • Chapter 18 - Fatigue management: the art of the state

  • from Section 4 - Summary and Conclusions
  • Edited by Nancy J. Wesensten
  • Book:
    Sleep Deprivation, Stimulant Medications, and Cognition
    Published online:
    05 September 2012
    Print publication:
    23 August 2012, pp 257-267

  • Summary

    Histamine (HA) is a biogenic amine, providing a number of functional roles throughout the body. HA release triggers inflammatory responses as a protective reaction against foreign pathogens. Released from basophils and mast cells in the periphery, HA causes increased vascular permeability and dilation of blood vessels to allow increased fluid infiltration into tissues which in turn induces swelling. Research designed to test the role of HA in mediating central nervous system (CNS) activity demonstrated that HA immunoreactive brain neurons actively fire action potentials and release HA during the wake phase but are essentially silent during sleep, supporting the hypothesis that increased HA tone is related to levels of wakefulness. Results of experiments investigating the effects of HA in the CNS, either through direct injection of HA or through pharmacological inhibition of its synthesis, show that increases in HA are positively correlated with amounts of wakefulness.

  • Chapter 9 - The potential for abuse of stimulants in chronically sleep-restricted populations

  • from Section 2 - Stimulant Reversal of Cognitive Deficits
  • Edited by Nancy J. Wesensten
  • Book:
    Sleep Deprivation, Stimulant Medications, and Cognition
    Published online:
    05 September 2012
    Print publication:
    23 August 2012, pp 122-135

  • Summary

    This chapter focuses on the neurotransmitter and neuromodulator systems involved in the regulation of wakefulness and sleep as well as the neurochemical responses to sleep loss. Wakefulness, rapid eye movement (REM), and non-REM (NREM) states were originally defined in mammals using measures of skull surface electrical brain activity, skeletal muscle activity, and eye movements. The two primary factors that determine the degree of human vigilance and sleepiness are the duration of prior wakefulness and circadian influences. Increases in homeostatic sleep need are associated with subjective sleepiness, objective sleepiness, diminished neurocognitive function, as well as neurochemical and neurophysiological changes. The ascending reticular activating system (ARAS) is comprised of the brainstem reticular formation and its ascending projections responsible for cortical activation and wakefulness. Electrophysiological and neurochemical data indicate that highest levels of orexinergic activity occur during active wakefulness, and greatly reduced activity is seen during NREM and REM sleep.

  • 1 - Normal sleep

  • from SECTION 1 - NORMAL SLEEP
  • Edited by Harold R. Smith, University of California, Irvine, Cynthia L. Comella, Birgit Högl
  • Book:
    Sleep Medicine
    Published online:
    08 August 2009
    Print publication:
    10 April 2008, pp 9-24

  • Summary

    Sleep is a complex behavior. It may be altered by many different factors including age, genetics, volitional control, timing, previous time awake, and environment. The state of wakefulness regularly alternates with the states of sleep. Polysomnography recordings are scored for movement time. Active wakefulness is characterized by a continuous electroencephalographic (EEG) theta activity associated with eye movements and muscular artifacts. Infants, children, and adolescents show different stages of maturation of sleep, in terms of polysomnographic patterns, architecture, and duration of sleep. The duration of nocturnal sleep depends on several factors. Voluntary control of the sleep time is among the most significant in human beings. Young adults report sleeping approximately 7.5 hours a night on weekday nights and 8.5 hours on weekend nights. The timing of sleep has obvious repercussions both on the duration and on the architecture of sleep.