Circadian organization in reindeer

Oort, Bob van; Tyler, N. J. C.; Gerkema, Menno P.; Folkow, Lars P.; Blix, Arnoldus Schytte; Stokkan, Karl‐Arne

doi:10.1038/4381095a

Cited by 170 publications

(143 citation statements)

References 9 publications

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“…Daily (≈24 h) rhythms of activity in free-living reindeer do not persist across the year (van Oort et al 2005; Figs. 1 and 2).…”

Section: Discussionmentioning

confidence: 99%

“…We therefore established critical ranges at both the solstices and the equinoxes with which to distinguish potential circadian from diel rhythms (van Oort et al 2005, supplementary information).…”

Section: Periodogram Analysismentioning

confidence: 99%

“…Remarkably, the animals remained active throughout the 24-h day throughout the year, and the pattern of their activity changed only slightly in response to the very large seasonal changes in photoperiod (van Oort et al 2005). In the present study, we investigated the degree of ultradian and seasonal organisation of locomotor activity in free-living reindeer in relation to their photic environment.…”

Section: Introductionmentioning

confidence: 99%

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Where clocks are redundant: weak circadian mechanisms in reindeer living under polar photic conditions

Oort

Tyler

Gerkema

et al. 2006

Naturwissenschaften

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“…Daily (≈24 h) rhythms of activity in free-living reindeer do not persist across the year (van Oort et al 2005; Figs. 1 and 2).…”

Section: Discussionmentioning

confidence: 99%

Section: Periodogram Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Where clocks are redundant: weak circadian mechanisms in reindeer living under polar photic conditions

Oort

Tyler

Gerkema

et al. 2006

Naturwissenschaften

Self Cite

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“…A exposição da B. jararacussu a longo período de luminosidade é capaz de desincronizar os osciladores circadianos responsáveis pela modulação da atividade locomotora, ocasionando uma signifi cativa fragmentação, com aumento global na atividade locomotora (Figura 3). Comportamentos singulares como estes foram descritos em algas, insetos, aves e mamíferos (Engelmann et al, 1978;Yoshii et al, 2004;Van Oort et al, 2005;Kumar et al, 2007), podendo estar presente em todos os relógios biológicos.…”

Section: Discussionunclassified

Padrões de atividade locomotora diária de Bothrops jararacussu (Serpentes: Viperidae): Uma resposta relacionada às condições ambientais de luminosidade ou a ritmos endógenos?

2008

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ResumoEmbora a maioria dos biologistas circadianos provavelmente assuma que os relógios circadianos controlem os padrões de atividade, também é sabido que estímulos ambientais podem mascarar os ritmos endógenos, quer pelo aumento ou pela supressão da atividade. A hipótese de que ritmos circadianos são geralmente controlados pelos ciclos exógenos, foi testada experimentalmente em Bothrops jararacussu. Neste estudo, investigamos a atividade locomotora sobre condições de luminosidade e escuro constantes durante 24 dias e comparamos com os controles, submetidos ao um ciclo de claro/escuro. Sob um ciclo claro/escuro foi observado um pico de atividade durante a fase noturna do ciclo, ritmo circadiano típico de espécies noturnas. Em condições constantes de luminosidade, espécimes de Bothrops jararacussu exibiram signifi cativa fragmentação com aumento global na atividade locomotora e, em escuro constante, signifi cativa supressão da atividade. Provavelmente, o ritmo circadiano é endógeno, primariamente sincronizado pela alternância de claro e escuro. Luminosidade constante induz desincronização e escuro constante bloqueio dos relógios circadianos. O signifi cado funcional destas alterações circadianas sugere pequena fl exibilidade na organização circadiana em resposta às condições do ambiente.Unitermos: atividade locomotora, Bothrops, fotoperíodo, ritmo circadiano, serpentes AbstractDaily patterns of the locomotor activity of Bothrops jararacussu (Serpentes: Viperidae): A response to environmental lighting conditions or an endogenous rhythm? While most circadian biologists would probably assume that circadian clocks drive activity patterns, it is also well known that environmental stimuli may mask endogenous rhythms by either increasing or suppressing activity.

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“…In other words, circadian rhythms are very important for the normal well-being of an animal because they enable an organism to anticipate and respond to environmental changes before they happen. In contrast, reindeer that live in the Arctic abandon daily activity rhythms during summers of constant light and winters of constant darkness since an endogenous circadian clock is apparently unnecessary without daily environmental changes to anticipate [14]. and closing in heliotrope plants, he asked what would happen to this rhythm in the absence of environmental cues by moving the plants to his dark wine cellar.…”

Section: Introductionmentioning

confidence: 99%

Even a stopped clock tells the right time twice a day: circadian timekeeping in Drosophila

Collins

Blau

2007

Pflugers Arch - Eur J Physiol

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"Even a stopped clock tells the right time twice a day, and for once I'm inclined to believe Withnail is right. We are indeed drifting into the arena of the unwell... What we need is harmony. Fresh air. Stuff like that." Bruce Robinson (1986, ref. 1). Although a stopped Drosophila clock probably does not tell the right time even once a day, recent findings have demonstrated that accurate circadian time-keeping is dependent on harmony between groups of clock neurons within the brain. Furthermore, when harmony between the environment and the endogenous clock is lost, as during jet lag, we definitely feel unwell. In this review, we provide an overview of the current understanding of circadian rhythms in Drosophila, focussing on recent discoveries that demonstrate how approximately 100 neurons within the Drosophila brain control the behaviour of the whole fly, and how these rhythms respond to the environment.

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Circadian organization in reindeer

Cited by 170 publications

References 9 publications

Where clocks are redundant: weak circadian mechanisms in reindeer living under polar photic conditions

Where clocks are redundant: weak circadian mechanisms in reindeer living under polar photic conditions

Padrões de atividade locomotora diária de Bothrops jararacussu (Serpentes: Viperidae): Uma resposta relacionada às condições ambientais de luminosidade ou a ritmos endógenos?

Even a stopped clock tells the right time twice a day: circadian timekeeping in Drosophila

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