Free-running circadian activity rhythms in free-living beaver (Castor canadensis)

1974 ◽  
Vol 92 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Jacques Bovet ◽  
Erwin F. Oertli
Keyword(s):  
Castor Canadensis ◽  
Circadian Activity ◽  
Free Living ◽  
Activity Rhythms ◽  
Free Running

Effects of Pregnancy and Parturition on Free-Running Circadian Activity Rhythms in the Rat

1987 ◽  
Vol 4 (2) ◽  
pp. 183-187 ◽  
Author(s):  
Alan M. Rosenwasser ◽  
Susanne J. Hollander ◽  
Norman T. Adler
Keyword(s):  
Circadian Activity ◽  
Activity Rhythms ◽  
Free Running

scholarly journals RCAN1 Knockout and Overexpression Recapitulate an Ensemble of Rest-activity and Circadian Disruptions Characteristic of Down Syndrome, Alzheimer’s Disease, and Normative Aging

2021 ◽  
Author(s):  
Helen Wong ◽  
Jordan M. Buck ◽  
Curtis Borski ◽  
Jessica Pafford ◽  
Bailey N. Keller ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Down Syndrome ◽  
Wheel Running ◽  
Activity Patterns ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Free Running ◽  
Rest Activity ◽  
Young Mice

Abstract Background: Regulator of calcineurin 1 (RCAN1) is overexpressed in Down syndrome (DS), but RCAN1 levels are also increased in Alzheimer's disease (AD) and normal aging. AD is highly comorbid among individuals with DS and is characterized in part by progressive neurodegeneration that resembles accelerated aging. Importantly, abnormal RCAN1 levels have been demonstrated to promote memory deficits and pathophysiology symptomatic of DS, AD, and aging. Anomalous diurnal rest-activity patterns and circadian rhythm disruptions are also common in DS, AD, and aging and have been implicated in facilitating age-related cognitive decline and AD progression. However, no prior studies have assessed whether RCAN1 dysregulation may also promote the age-associated alteration of rest-activity profiles and circadian rhythms, which could in turn contribute to neurodegeneration in DS, AD, and aging. Methods: The present study examined the impacts of RCAN1 deficiency and overexpression on the photic entrainment, circadian periodicity, intensity and distribution, diurnal patterning, and circadian rhythmicity of wheel running in young (3-6 months old) and aged (9-14 months old) mice. All data were initially analyzed by multifactorial ANOVA with variables of genotype, age, treatment, and sex considered as dependent variables.Results: We found that daily RCAN1 levels in the hippocampi of light-entrained young mice are generally constant and that balanced RCAN1 expression is necessary for normal circadian locomotor activity rhythms. While the light-entrained diurnal period was unaltered, RCAN1-null and -overexpressing mice displayed lengthened endogenous (free-running) circadian periods like mouse models of AD and aging. In light-entrained young mice, RCAN1 knockout and overexpression also recapitulated the general hypoactivity, diurnal rest-wake pattern fragmentation, and attenuated amplitudes of circadian activity rhythms reported in DS, preclinical and clinical AD, healthily aging individuals, and rodent models thereof. Under constant darkness, RCAN1-null and -overexpressing mice displayed altered locomotor behavior indicating circadian clock dysfunction. Using the Dp(16)1Yey/+ (Dp16) mouse model for DS, which expresses three copies of Rcan1, we found reduced wheel running activity and rhythmicity in both light-entrained and free-running young Dp16 mice like young RCAN1-overexpressing mice. Critically, these diurnal and circadian deficits were rescued in part or entirely by restoring Rcan1 to two copies in Dp16 mice. Conclusions: Collectively, this study's findings suggest that both loss and aberrant gain of RCAN1 precipitate anomalous light-entrained diurnal and circadian activity patterns emblematic of DS, AD, and aging.

Social cues modulate free-running circadian activity rhythms in the diurnal rodent, Octodon degus

1997 ◽  
Vol 273 (2) ◽  
pp. R797-R804 ◽  
Author(s):  
N. Goel ◽  
T. M. Lee
Keyword(s):  
Active Phase ◽  
Social Cues ◽  
Constant Darkness ◽  
Circadian Activity ◽  
Mutual Synchronization ◽  
Octodon Degus ◽  
Activity Rhythms ◽  
Female Partners ◽  
Free Running ◽  
Activity Onset

Two experiments assessed the effects of social cues and daily disturbance on the circadian locomotor activity rhythms of Octodon degus housed in constant darkness. In experiment 1, females in free-running conditions were housed alone or with entrained female partners ("donors") in cages on either side of a mesh barrier. Donors were removed daily and entrained to 1 h of light, and as a control, the cages of singly housed animals were rustled daily coincident with donor removal and replacement. None of the animals housed alone entrained to daily disturbances presented during the active phase, and seven of eight degus failed to show changes in the circadian period (tau) or phase of their rhythms. In contrast, although the presence of entrained donors did not elicit full entrainment of free-running rhythms, five of six animals demonstrated partial entrainment for 5-12 days (of 30 days), four of six altered phase of activity onset, and six of six lengthened tau of circadian rhythms. In experiment 2, females whose free-running circadian activity rhythms were at least 10 h out of phase were housed together in pairs. None of the pairs demonstrated mutual synchronization of their activity rhythms, although 8 of 12 degus modified phase of activity onset and 9 of 12 animals altered tau. We conclude social information in the absence of light, is sufficient for partial entrainment and for changes in tau and phase of free-running rhythms in this diurnal rodent.

Comparative locomotor activity patterns in the portunid crabs Liocarcinus holsatus and L. depurator

1991 ◽  
Vol 71 (1) ◽  
pp. 1-10 ◽  
Author(s):  
P. Abelló ◽  
D. G. Reid ◽  
E. Naylor
Keyword(s):  
Locomotor Activity ◽  
Activity Patterns ◽  
High Tide ◽  
Sandy Beaches ◽  
Maximum Activity ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Sublittoral Zone ◽  
Free Running ◽  
Behavioural Mechanism

The free-running locomotor activity rhythms of freshly-captured swimming crabs Liocarcinus holsatus and L. depurator have been studied in constant conditions in the laboratory. L. holsatus captured in the intertidal zone of sandy beaches showed strong circatidal activity rhythms with maximum activity at high tide. L. holsatus captured in the sublittoral zone had a clear tendency to show circadian activity rhythms with highest activity during day-time hours. L. depurator occurred only sublittorally and showed circadian activity patterns with highest activity during the night. Exposure to hydrostatic pressure cycles of tidal amplitude and periodicity, entrained strong circatidal activity rhythms in previously arhythmic L. holsatus. This activity pattern also showed a marked circadian component. Exposure to the same regime entrained a circadian rhythm, but not a circatidal rhythm in L. depurator. In the sublittoral zone L. depurator is active mainly during the night, whereas L. holsatus, is active mainly during the day. This may constitute a behavioural mechanism for minimizing competitive interactions between these two sympatric crabs.

Effects of daily melatonin injections on activity rhythms of rats in constant light

1987 ◽  
Vol 253 (1) ◽  
pp. R101-R107 ◽  
Author(s):  
M. J. Chesworth ◽  
V. M. Cassone ◽  
S. M. Armstrong
Keyword(s):  
Locomotor Activity ◽  
Saline Solution ◽  
Constant Light ◽  
Constant Darkness ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Melatonin Administration ◽  
Free Running ◽  
Circadian Patterns ◽  
Phase Relationships

Although from pinealectomy studies the pineal body does not appear to participate in the generation of circadian rhythms of mammals, daily injections of the pineal hormone melatonin entrain free-running locomotor activity rhythms of rats in constant darkness. The aim of the present study was to determine whether rats whose circadian activity and drinking rhythms were disrupted in constant light (LL) could be synchronized by daily melatonin administration. Rats were subjected to a regime of gradually increasing photoperiod until they were maintained in LL. Rats whose rhythms became disrupted or showed intact free-running rhythms were injected daily with either melatonin (1 mg/kg) or vehicle (ethanol-saline) solution. Daily melatonin injections either synchronized or partly synchronized disrupted circadian patterns of activity. In contrast to previous findings from experiments conducted in constant darkness, melatonin did not entrain but only partly synchronized intact free-running rhythms. Results are interpreted in terms of melatonin acting on the coupling or phase relationships between oscillators generating circadian locomotor activity rhythms.

Circadian activity rhythms in cockroaches. I. The free-running rhythm in steady-state

1960 ◽  
Vol 55 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Shepherd K. de F. Roberts
Keyword(s):  
Steady State ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Free Running

Effects of ethanol intake and ethanol withdrawal on free-running circadian activity rhythms in rats

2005 ◽  
Vol 84 (4) ◽  
pp. 537-542 ◽  
Author(s):  
A ROSENWASSER ◽  
M FECTEAU ◽  
R LOGAN
Keyword(s):  
Ethanol Intake ◽  
Ethanol Withdrawal ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Free Running

Free-running circadian activity rhythms during long-term clonidine administration in rats

1990 ◽  
Vol 35 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Alan M. Rosenwasser
Keyword(s):  
Circadian Activity ◽  
Activity Rhythms ◽  
Free Running

753 The role of circadian activity rhythms in depressive symptoms among female nursing students

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A293-A294
Author(s):  
Xin Zhang ◽  
Shih-Yu Lee
Keyword(s):  
Nursing Education ◽  
Depressive Symptoms ◽  
Nursing Students ◽  
Conceptual Model ◽  
Depression Scale ◽  
Psychological Problems ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Wrist Actigraphy ◽  
Insomnia Symptoms

Abstract Introduction Depression is prevalent among nursing students. Rumination and sleep-wake rhythms are associated to mental illness; however, no clear path has been found. This exploratory study aimed to examine the associations among circadian activity rhythms (CAR), rumination, and depressive symptoms in female nursing students; further, to test a hypothesized CAR conceptual model. Methods A total of 148 female nursing junior students in China completed a battery of questionnaires, including Athens Insomnia Scale (AIS), Ruminative Responses Scale (RRS), and Self-rating Depression Scale (SDS). Wrist actigraphy was used to collect total sleep time, CAR, and acrophase (time of the peak of the fitted activity curve). The path analysis was explored by using SPSS and AMOS. Results The mean age of the students was 20.64 years (SD = 0.86). About 58.8% of the participants were either mild or moderate depressed. About 93.9% of the students reported significant insomnia symptoms (AIS scores >6). Rumination was measured by the RRS (M= 2.01, SD = 0.54), and students scored higher in brooding than that of reflective pondering (2.07 vs. 1.95). The average of TST was 394.59 minutes (SD = 51.92). The CAR ranged from 0.40 to 0.98, with a mean of 0.75 (SD = 0.11). The acrophase ranged from 12:46 to 20:14 (median 16:30), with a later acrophase indicates of a more delayed circadian phase. The final model shows satisfactory fit (χ2= 2.238, p= .327); a better CAR can indirectly reduce depressive symptoms by directly reducing brooding (B = -1.149) and improving insomnia symptoms (B = -6.6443). Conclusion In order to prevent psychological problems of nursing students, ruminating and CAR should be part of health screening. The novel conceptual model provides a basis for reforming nursing education to prevent psychological problems. Support (if any) Chinese National Natural Science Foundation [71603279]

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