English
norskBlar i forfatter Artikler, rapporter og annet (arktisk og marin biologi) "Wagner, Gabriela"
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Body Temperature and Activity Rhythms Under Different Photoperiods in High Arctic Svalbard ptarmigan (Lagopus muta hyperborea)
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-03-08)Organisms use circadian rhythms to anticipate and exploit daily environmental oscillations. While circadian rhythms are of clear importance for inhabitants of tropic and temperate latitudes, its role for permanent residents of the polar regions is less well understood. The high Arctic Svalbard ptarmigan shows behavioral rhythmicity in presence of light-dark cycles but is arrhythmic during the polar ... -
Effects of photoperiod extension on clock gene and neuropeptide RNA expression in the SCN of the Soay Sheep
(Journal article; Tidsskriftartikkel; Peer reviewed, 2016)In mammals, changing daylength (photoperiod) is the main synchronizer of seasonal functions. The photoperiodic information is transmitted through the retino-hypothalamic tract to the suprachiasmatic nuclei (SCN), site of the master circadian clock. To investigate effects of day length change on the sheep SCN, we used in-situ hybridization to assess the daily temporal organization of expression of ... -
Evidence for circadian-based photoperiodic timekeeping in Svalbard ptarmigan, the northernmost resident bird
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-29)The high Arctic archipelago of Svalbard (74°–81° north) experiences extended periods of uninterrupted daylight in summer and uninterrupted night in winter, apparently relaxing the major driver for the evolution of circadian rhythmicity. Svalbard ptarmigan (<i>Lagopus muta hyperborea</i>) is the only year-round resident terrestrial bird species endemic to the high Arctic and is remarkably adapted to ... -
Photoperiodic induction without light-mediated circadian entrainment in a High Arctic resident bird
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-21)Organisms use changes in photoperiod to anticipate and exploit favourable conditions in a seasonal environment. While species living at temperate latitudes receive day length information as a year-round input, species living in the Arctic may spend as much as two-thirds of the year without experiencing dawn or dusk. This suggests that specialised mechanisms may be required to maintain seasonal ... -
Reindeer in the Arctic reduce sleep need during rumination
(Journal article; Tidsskriftartikkel, 2023-12-22)Timing and quantity of sleep depend on a circadian (ca 24-h) rhythm and a specific sleep requirement. Sleep curtailment results in a homeostatic rebound of more and deeper sleep, the latter reflected in increased electroencephalographic (EEG) slow-wave activity (SWA) during non-rapid eye movement (NREM) sleep. Circadian rhythms are synchronized by the light-dark cycle but persist under constant ...
