Splitting of the circadian activity rhythm in common marmosets (Callithrix j. jacchus Primates)

1989 ◽  
Vol 45 (11-12) ◽  
pp. 1112-1115 ◽  
Author(s):  
U. Schardt ◽  
I. Wilhelm ◽  
H. G. Erkert
Keyword(s):  
Activity Rhythm ◽  
Circadian Activity ◽  
Common Marmosets ◽  
Circadian Activity Rhythm

Effect of Nest Box Availability on the Circadian Activity Rhythm of Common Marmosets (Callithrix jacchus)

2009 ◽  
Vol 80 (3) ◽  
pp. 175-188 ◽  
Author(s):  
Fabiana B. Gonçalves ◽  
Aline S. Belísio ◽  
Carolina V.M. Azevedo
Keyword(s):  
Activity Rhythm ◽  
Callithrix Jacchus ◽  
Circadian Activity ◽  
Common Marmosets ◽  
Nest Box ◽  
Circadian Activity Rhythm

Response of hamster circadian system to transitions between light and darkness

1986 ◽  
Vol 250 (4) ◽  
pp. R708-R711 ◽  
Author(s):  
H. E. Albers
Keyword(s):  
Activity Rhythm ◽  
Phase Shifts ◽  
Circadian System ◽  
Circadian Cycle ◽  
Circadian Activity ◽  
Syrian Hamsters ◽  
Circadian Activity Rhythm ◽  
Free Running ◽  
Activity Onset

The effects of exposure to sudden transitions from dark to light (DL) and light to dark (LD) were determined on the free-running circadian activity rhythm of Syrian hamsters. The activity rhythm was phase delayed by 1-2 h by DL transitions provided during the 12-h interval before activity onset (subjective day). In contrast, DL transitions produced phase advances of approximately 1 h 2-12 h after activity onset. LD transitions tended to produce phase advances throughout the circadian cycle. During the subjective day, LD transitions resulted in phase advances of up to 4 h. After the onset of activity, LD transitions produced phase advances of a lesser magnitude than during the subjective day. In addition, some phase delays were also observed. When the phase shifts produced by DL and LD transitions were combined additively these transitions could account for the phase shifts previously reported for brief pulses of light.

Twilight transitions promote circadian entrainment to lengthening light-dark cycles

1996 ◽  
Vol 271 (3) ◽  
pp. R813-R818 ◽  
Author(s):  
Z. Boulos ◽  
M. Macchi ◽  
M. Terman
Keyword(s):  
Activity Rhythm ◽  
Constant Darkness ◽  
Circadian Activity ◽  
Nest Box ◽  
Circadian Activity Rhythm ◽  
Nest Boxes ◽  
Upper Limit ◽  
Upper Limits

The upper limits of entrainment of the circadian activity rhythm were compared in hamsters initially exposed to daily light-dark (LD) cycles with either abrupt (LD-rectangular) or simulated twilight (LD-twilight) transitions. Daytime illuminance (10 lx) and the total amount of light emitted per day were the same under the two LD cycles. One-half of the animals in each condition had access to dark nest boxes. The period of the LD cycles was then increased from 24 to 26 h, by 5 min per day. All animals in LD-twilight remained entrained to the lengthening cycle, whereas 60% of those in LD-rectangular began to free run well before the period of the cycle reached 26 h. These effects were independent of nest box availability. The lengthening LD cycles exerted clear aftereffects on the period of the rhythms in constant darkness, the magnitude of which was related to the efficacy of prior entrainment. The results indicate that twilight transitions raise the upper limit of entrainment to LD cycles, suggesting that their inclusion increases the strength of the LD zeitgeber.

scholarly journals P3-149: Circadian activity rhythm patterns in nondemented older women and cognitive function 5 years later

2013 ◽  
Vol 9 ◽  
pp. P608-P608
Author(s):  
Christine Walsh ◽  
Greg Tranah ◽  
Katie Stone ◽  
Terri Blackwell ◽  
Susan Redline ◽  
...  
Keyword(s):  
Cognitive Function ◽  
Older Women ◽  
Activity Rhythm ◽  
Circadian Activity ◽  
Circadian Activity Rhythm
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