Light pulses entrain the circadian activity rhythm of a diurnal rodent (Ammospermophilus leucurus).

@article{Pohl1983LightPE,
  title={Light pulses entrain the circadian activity rhythm of a diurnal rodent (Ammospermophilus leucurus).},
  author={H. Pohl},
  journal={Comparative biochemistry and physiology. B, Comparative biochemistry},
  year={1983},
  volume={76 4},
  pages={
          723-9
        }
}
  • H. Pohl
  • Published 1983
  • Biology, Medicine
  • Comparative biochemistry and physiology. B, Comparative biochemistry
Circadian rhythms of wheel-running activity of the antelope ground squirrel (Ammospermophilus leucurus) were entrained by light-dark cycles (LD: 100 1x vs total darkness) with periods (T) between ca 23.75 and 24.75 hr. Two 1-hr light pulses per cycle ('skeleton photoperiods') with T = 24.25 hr as well as one 1-hr light pulse per cycle with Ts of 23.75 and 24.25 hr were effective in entraining the circadian activity rhythms in at least 50% of the antelope ground squirrels. Phase and period… Expand
The Two-Oscillator Circadian System of Tree Shrews (Tupaia belangeri) and Its Response to Light and Dark Pulses
TLDR
The wheel-running activity rhythm of tree shrews housed in constant darkness phase-advanced following a 3-hr light pulse at circadian time (CT) 21 to indicate asymmetry in the coupling between the components. Expand
Circadian rhythms of body temperature and locomotor activity in the antelope ground squirrel, Ammospermophilus leucurus.
TLDR
Daytime temperatures were higher than nighttime temperatures even when comparing short episodes of nocturnal activity that were as intense as diurnal activity, suggesting that although muscular thermogenesis associated with locomotor activity can modify the level of body temperature, the circadian rhythm of bodyTemperature is not simply a consequence of the circadian Rhythm of activity. Expand
The circadian system of the Turkish hamster, Mesocricetus brandti: responses to light.
  • H. Pohl
  • Biology, Medicine
  • Comparative biochemistry and physiology. A, Comparative physiology
  • 1985
TLDR
The data support the hypothesis derived from experiments on Syrian hamsters that the range of the PRC is functionally related with alpha, possibly reflecting the phase relations (coupling) between two oscillators. Expand
Circadian activity rhythms in the solitary Cape molerat (Georychus capensis: Bathyergidae) with some evidence of splitting
TLDR
Data show that, despite degenerate retinae, G. capensis are capable of perceiving light at the level of the circadian pacemaker, can entrain endogenous activity oscillators to fixed photoperiods, and display evidence of a free-running activity oscillator. Expand
Light-induced uncoupling of multioscillatory circadian system in a diurnal rodent, Asian chipmunk.
  • S. Honma, K. Honma
  • Medicine
  • American journal of physiology. Regulatory, integrative and comparative physiology
  • 1999
TLDR
It is suggested that light affects the oscillatory coupling not only of the major oscillators but also of constitutional oscillators, each of which is constituted by multiple oscillators. Expand
Light-induced uncoupling of multioscillatory circadian system in a diurnal rodent, Asian chipmunk.
TLDR
It is suggested that light affects the oscillatory coupling not only of the major oscillators but also of constitutional oscillators, each of which is constituted by multiple oscillators. Expand
Effects of twilights on circadian entrainment patterns and reentrainment rates in squirrel monkeys
TLDR
The results provide no evidence that the inclusion of twilight transitions affected the strength of the LD Zeitgeber, and suggest that the observed differences in the daily patterns reflected direct effects of light intensity on locomotor activity and body temperature rather than an effect of twilights on circadian entrainment mechanisms. Expand
Circadian chronotypes among wild-captured west Andean octodontids.
TLDR
It is proposed that crepuscular diurnal pattern observed in O. degus is a recent acquisition among the octodontid lineage, and colonies observed in the field could not be explained solely by photic entrainment, since social and/or masking processes appear to be operative. Expand
Circadian Performance of Suprachiasmatic Nuclei (SCN)-Lesioned Antelope Ground Squirrels in a Desert Enclosure
TLDR
Circadian activity parameters of 53 white-tailed antelope ground squirrels were measured to determine the role of the suprachiasmatic nuclei (SCN) pacemaker in their health and survival. Expand
THE EFFECT OF REPEATED PULSES OF LIGHT AT THE SAME TIME ON PERIOD RESPONSES OF THE RAT CIRCADIAN PACEMAKER
TLDR
Modulation of circadian period following light-induced phase responses was examined by assessing the period of running wheel activity onset and results do not support a simple velocity model of the pacemaker. Expand
...
1
2
3
...

References

SHOWING 1-10 OF 11 REFERENCES
Photoperiodic control of circadian activity rhythms in diurnal rodents
TLDR
The data suggest that the parametric and non-parametric contributions to entrainment are different in these two rodent species. Expand
Phase control of circadian activity in the antelope ground squirrel
TLDR
Wheel‐running activity of forty antelope ground squirrels, Ammospermophilus leucurus, was monitored for several months in both an outdoor cage and in the laboratory to demonstrate a response curve. Expand
Entrainment of Circadian Activity Rhythms in Squirrels
TLDR
It was found that, at least with red squirrels, phase and period shifting occur together and presumably act synergistically in the entrainment process. Expand
Photoperiod and Entrainment of Circadian Activity in the Antelope Ground Squirrel
TLDR
The effect of daylength on the timing of overt activity in the antelope ground squirrel, Ammospermophilus leucurus, is focused on. Expand
Circadian activity of the red squirrel,Tamiasciurus hudsonicus, in continuous darkness and continuous illumination
  • K. R. Kramm
  • Biology, Medicine
  • International journal of biometeorology
  • 1975
TLDR
Data from 58 red squirrels taken directly from the field and placed in either total darkness (DD) or continuous illumination (LL) 500 lux support Pittendrigh's (1965) entrainment model. Expand
Free‐running rhythms and patterns of circadian entrainment in three species of diurnal rodents
TLDR
Activity rhythms of 3 species of day‐active sciurid rodents under various constant lighting conditions and in L/D schedules were studied, with the exact response dependent upon the phase relationship of activity to the new light schedule. Expand
Characteristics and Variability in Entrainment of Circadian Rhythms to Light in Diurnal Rodents
TLDR
In a comparative analysis of functional aspects of circadian pacemakers in four species of nocturnal rodents, Pittendrigh and Daan have shown that various pacemaker properties, such as the stability of the period, the shape of the phase response curve (PRC), the light-dependence of τ, and the ranges of entrainment to light cycles, vary interdependently. Expand
Circadian Locomotor Rhythms of Rodents in the Arctic
TLDR
The conclusion that in the arctic, even during the summer, the environmental light cycle is the principal entraining agent of the endogenous rhythm is supported. Expand
Circadian rhythms: influences of internal and external factors on the period measured in constant conditions.
  • J. Aschoff
  • Biology, Medicine
  • Zeitschrift fur Tierpsychologie
  • 1979
TLDR
Most of the data available on the period tau of freerunning circadian rhythms, measured in constant conditions, are reviewed, with emphasis on the effects of light intensity and ambient temperature on tau. Expand
Virtual synchronization towards the limits of the range of entrainment.
  • R. Wever
  • Mathematics, Medicine
  • Journal of theoretical biology
  • 1972
TLDR
The consideration of the borderline cases of entrainment forces the apparently conflicting view that a phase response curve cannot be measured in a self-sustained oscillation without a change in the response curve itself. Expand
...
1
2
...