CIRCADIAN LOCOMOTOR ACTIVITY AND ITS ENTRAINMENT BY FOOD IN THE CRAYFISH PROCAMBARUS CLARKI

1994 ◽  
Vol 190 (1) ◽  
pp. 9-21 ◽  
Author(s):  
F F De Miguel ◽  
H Aréchiga
Keyword(s):  
Locomotor Activity ◽  
Activity Rhythm ◽  
Food Reinforcement ◽  
Continuous Light ◽  
Food Delivery ◽  
Continuous Darkness ◽  
Locomotor Activity Rhythm ◽  
Activity Peak ◽  
Free Running ◽  
Two Peaks

The aim of our experiments has been to study the effect of light and food in the locomotor activity rhythm of the crayfish Procambarus clarki. Experiments were carried out under light:dark (LD) cycles of 12 h:12 h, under continuous darkness (DD) and under continuous light (LL). Under LD cycles, two peaks of activity were observed during the night phase of the cycle, while resting was characteristic of the day phase. Under DD or LL, it was possible to follow a free-running rhythm with a periodicity of 22.3±0.84 h in DD and 24.8±0.27 h in LL, typical of circadian rhythms of nocturnal species. A single delivery of food in the day phase of the LD cycle resulted in an outburst of locomotor activity that lasted for several hours. In the ensuing days, an activity peak appeared in phase with the time of food delivery. The food-related activity peak could be followed for up to 2 weeks without food reinforcement. Under DD and LL, food induced an activity rhythm in previously arrhythmic animals. Here the period was longer than 24 h in DD (26.2±0.12 h) and shorter in LL (22.5±0.46 h). Together, these results strongly suggest that light and food may play a role entraining a locomotor activity rhythm in crayfish.

Splitting of the locomotor activity rhythm in rats by exposure to continuous light

1983 ◽  
Vol 244 (4) ◽  
pp. R573-R576 ◽  
Author(s):  
Phyllis W. Cheung ◽  
Charles E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Estrous Cycle ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Female Rats ◽  
Locomotor Rhythm ◽  
Estrous Cycles ◽  
Locomotor Activity Rhythm ◽  
Active Portion ◽  
Free Running

Female rats exposed to low intensities (0.1–1.5 lx) of continuous light (LL), displayed regular estrous cycles and free-running circadian rhythms of locomotor activity. In most rats, as the intensity of LL was increased to >2.0 lx, components within the active portion (α) of the locomotor rhythm remained synchronized as the periodicity of the rhythm lengthened. However, in a few rats agr split into two components; one of which free-ran with a period shorter than 24 h, while the other free-ran with a period longer than 24 h. As soon as the two components became maximally separated they spontaneously rejoined. In most rats, estrous cycles ceased shortly after the intensity of LL was increased to >2.0 lx even though the locomotor activity rhythm retained its unsplit free-running nature. These observations suggest that the multiple oscillators that control the rhythms of locomotor activity and the estrous cycle are normally coupled to one another. In certain intensities of LL, these oscillators uncouple and free-run with different periodicities, a condition which causes estrous cycles to cease and sometimes produces a split locomotor activity rhythm. circadian rhythm; oscillators; estrous cycle Submitted on November 9, 1981 Accepted on October 11, 1982

Latitudinal variation in locomotor activity rhythm in adult Drosophila ananassae

1999 ◽  
Vol 77 (6) ◽  
pp. 865-870 ◽  
Author(s):  
Dilip S Joshi
Keyword(s):  
Locomotor Activity ◽  
Activity Rhythm ◽  
Drosophila Ananassae ◽  
Lower Latitude ◽  
Constant Darkness ◽  
Phase Angle Difference ◽  
Activity Peak ◽  
Free Running ◽  
Two Peaks ◽  
Adult Drosophila

The parameters of the circadian rhythm of adult locomotor activity in strains of Drosophila ananassae originating between 6° and 34°N were variable and latitude-dependent. Two representative southern strains became active before sunrise, but one representative northern strain began activity after sunrise in nature. During entrainment to a 12 h light (L) : 12 h dark (D) cycle in the laboratory, the southern strains showed two peaks of activity, at the beginning and end of photophase, whereas the northern strains showed a single uninterrupted activity peak starting about 3 h after the lights-on. Among the strains, the phase angle difference (Ψ) during entrainment to 12 h L : 12 h D varied by about 5 h, the period of free-running rhythm(τ) in constant darkness by 3 h, the duration of the activity phase (α) by 7 h, and the duration of the resting phase (ρ) by 10 h. Lower latitude was correlated with an early Ψ (r = 0.977), a short τ (r = 0.975), a prolonged α (r = -0.995), a short ρ (r = 0.995) and a large α/ρ ratio (r = -0.963).

Phase-response and Aschoff illuminance curves for locomotor activity rhythm of the rat

1984 ◽  
Vol 246 (3) ◽  
pp. R299-R304 ◽  
Author(s):  
T. L. Summer ◽  
J. S. Ferraro ◽  
C. E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Wheel Running ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Phase Response ◽  
Sprague Dawley ◽  
Continuous Darkness ◽  
Light Pulses ◽  
Log Steps

A phase-response curve (PRC) for the circadian rhythm of locomotor activity was constructed for female Sprague-Dawley-derived rats kept in continuous darkness (DD) except when given a 1-h light pulse (150 lx) once each 2 wk. By use of the circadian onset of wheel running as the phase-reference point, the free-running period (tau) in DD was 24.09 h. Maximum phase delays and phase advances occurred in response to light pulses given during the first 5 and last 6 h of activity, respectively. The delay-to-advance ratio (D/A) of the PRC was 1.5. In a separate group of rats exposed to continuous light, tau increased by 1.45 h as illuminance was increased in log steps from 0.1 to 10 lx, thus demonstrating the Aschoff effect in rats. This increase in tau was large, considering the relatively low D/A of the PRC, suggesting that factors in addition to the D/A contribute to the Aschoff effect.

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