A longitudinal study of bioelectric activity in the pre‐ and post‐hatch chick

Speciale, Samuel G.; Nowaczyk, T.; Jouvet, Michel

doi:10.1002/dev.420090607

Cited by 14 publications

(6 citation statements)

References 28 publications

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“…This is because the depressed muscle tone, presence of eye movements and autonomic instability (including irregular heart and breathing rates), which are all integral to REM sleep (Rattenborg et al 2000), were not measured in most studies. When eye and limb movements were measured (Corner and Bot 1967;Corner et al 1967Corner and Bakhuis 1969;Speciale et al 1976), however, REM or paradoxical sleep, not 'wakefulness', appeared to be the more likely explanation for such EEG epochs. Third, the reports of brief periods of possible 'wakefulness' in chicks which were refolded into glass eggs several hours to days after hatching (Corner et al 1973a;Bakhuis and van de Nes 1979;Bakhuis and Bour 1980) cannot be taken as defi nitive regarding the pre-hatched state, in view of the marked changes in the physiological environment of the chick's brain which are likely to accompany hatching.…”

Section: Discussionmentioning

confidence: 95%

“…First, the evidence shows that sleep-like states predominate (Peters et al 1965;Ookawa 1972;Corner et al 1973a;Speciale et al 1976;Bakhuis and van de Nes 1979;Bakhuis and Bour 1980). Second, the short periods of pre-hatching EEG activity described by some as 'wakefulness' (Ookawa 1972;Corner et al 1973a;Bakhuis and van de Nes 1979;Bakhuis and Bour 1980) in fact could not be distinguished from similar EEG patterns that are present during REM sleep.…”

Section: Discussionmentioning

confidence: 95%

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Birth and hatching: Key events in the onset of awareness in the lamb and chick

Mellor¹,

Diesch²

2007

New Zealand Veterinary Journal

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The neuroanatomical and neurophysiological development of the embryo and fetus and unique features of the physiological environment of the fetal brain, features which are lost at birth, support recent conclusions that under normal circumstances awareness (or consciousness) is probably not exhibited by the ovine embryo-fetus before birth and that it appears for the first time only after birth. However, there has apparently been no evaluation of whether or not similar mechanisms modulate awareness-related functions in domestic chicks before and after hatching. This comparative review, in seeking to rectify this, arrived at the following conclusions. First, the neural apparatus of both lambs and chicks appears to be too immature to support any states resembling awareness during at least the first half of pregnancy or incubation. Second, electroencephalographic (EEG) activity, which evolves subsequently, shows that states of sleep-like unconsciousness are likely to be continuously present in lambs until after birth, and that such states at least predominate in chicks until after hatching. Third, as in fetal lambs, epochs of so-called 'wakefulness' previously reported in chick embryos do not seem likely to represent short periods of awareness in ovo. Fourth, several neurosuppressive mechanisms, with some unique features, also operate or have the potential to operate in chicks before hatching, but a dearth of published information currently hinders a full comparison with those demonstrated to operate in fetal lambs. Fifth, contradicting the intuitive perception that vocalisation pre-hatching by the chick indicates the presence of awareness, published evidence suggests that vocalisation before and during hatching occurs mostly during EEG states indicating sleep-like unconsciousness. Sixth, as seems to be the case for newborn lambs after birth, it is possible that demonstrable awareness may appear for the first time only after hatching in chicks, presumably through waning neurosuppression and burgeoning neuroactivation, but such awareness seems to take longer to manifest itself. However, additional research in chicks is recommended to further assess this suggestion. Particular attention should be given to the status of vocal interactions between hen and chick which begin several days before hatching, and to the operation of neurosuppressive and neuroactivating mechanisms throughout the last 40% of incubation and during and after hatching.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 95%

Birth and hatching: Key events in the onset of awareness in the lamb and chick

Mellor¹,

Diesch²

2007

New Zealand Veterinary Journal

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“…While REM sleep can be first identified 1 – 2 d before chicken embryos hatch [38,39], age-related changes in REM sleep have been examined primarily following hatching. Several studies have reported that REM sleep as a % of total sleep time (%REM sleep) declines with age from higher amounts occurring shortly (0 – 8 h) after hatching [30,31,40,41]. However, others have reported lower %REM sleep in newly hatched chicks [33].…”

Section: Discussionmentioning

confidence: 99%

Linking melanism to brain development: expression of a melanism-related gene in barn owl feather follicles covaries with sleep ontogeny

et al. 2013

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BackgroundIntra-specific variation in melanocyte pigmentation, common in the animal kingdom, has caught the eye of naturalists and biologists for centuries. In vertebrates, dark, eumelanin pigmentation is often genetically determined and associated with various behavioral and physiological traits, suggesting that the genes involved in melanism have far reaching pleiotropic effects. The mechanisms linking these traits remain poorly understood, and the potential involvement of developmental processes occurring in the brain early in life has not been investigated. We examined the ontogeny of rapid eye movement (REM) sleep, a state involved in brain development, in a wild population of barn owls (Tyto alba) exhibiting inter-individual variation in melanism and covarying traits. In addition to sleep, we measured melanistic feather spots and the expression of a gene in the feather follicles implicated in melanism (PCSK2).ResultsAs in mammals, REM sleep declined with age across a period of brain development in owlets. In addition, inter-individual variation in REM sleep around this developmental trajectory was predicted by variation in PCSK2 expression in the feather follicles, with individuals expressing higher levels exhibiting a more precocial pattern characterized by less REM sleep. Finally, PCSK2 expression was positively correlated with feather spotting.ConclusionsWe demonstrate that the pace of brain development, as reflected in age-related changes in REM sleep, covaries with the peripheral activation of the melanocortin system. Given its role in brain development, variation in nestling REM sleep may lead to variation in adult brain organization, and thereby contribute to the behavioral and physiological differences observed between adults expressing different degrees of melanism.

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“…Research efforts have largely concerned the use of the EEG either as an indicator of the general integrity of the nervous system (Corner & Bakhuis, 1969;Muller & Scheich, 1986) or as a measure of specific brain states such as sleep cycles and other EEG rhythm defined states (Corner, Bakhuis, & van Wingerden, 1973;Ookawa & Gotoh, 1965;Ookawa & Takagi, 1968;Speciale, Correspondence to: M. Hunter Contract grant sponsor: University of Newcastle Contract grant number: RMC 280-1086 Nawaczyk, & Jouvet, 1976). Of those studies using the EEG as a measure of the functional integrity of the chicken nervous system, a major interest has been to plot the embryonic development of the chicken brain.…”

mentioning

confidence: 99%