Temperature Sensitive Events between Photoreceptor and Circadian Clock?

1975 ◽  
Vol 30 (3-4) ◽  
pp. 240-244 ◽  
Author(s):  
Ursula Hamm ◽  
M Aroli ◽  
K Chandrashekaran ◽  
W Olfgang Engelmann
Keyword(s):  
Low Temperature ◽  
Response Curve ◽  
Time Course ◽  
Phase Response Curve ◽  
Phase Response ◽  
Phase Shifting ◽  
Wave Form ◽  
Temperature Sensitive ◽  
Slowing Down ◽  
Light Pulses

Abstract The phase shifting action of low temperature pulses of 6 °C and 2 h duration administered to the various phases of the Drosophila pseudoobscura circadian rhythm and the action of light pulses given 30 min after the beginning of these low temperature pulses have been investigated. The phase response curve obtained from experiments with light pulses during low temperature cannot be ex­ plained on the basis of a straightforward and sequential phase shifting of the oscillation by the various transitions in the pulses. The response curve, after the slight phase shifting action of the temperature pulses is corrected for, resembles the standard phase response curve 4 for light pulses (at 20 °C) in its wave form but not in its time course. Our curve is shifted in time in a manner that indicates that the light pulses accompanying the low temperature pulses arrived at phase points 1.5 h later than the actual phases at which they were given. We attribute this delay to a slowing down of the information that is apparently transmitted by a process that is temperature dependent.

scholarly journals A Phase Response Curve to Single Bright Light Pulses in Human Subjects

2003 ◽  
Vol 549 (3) ◽  
pp. 945-952 ◽  
Author(s):  
Sat Bir S. Khalsa ◽  
Megan E. Jewett ◽  
Christian Cajochen ◽  
Charles A. Czeisler
Keyword(s):  
Response Curve ◽  
Phase Response Curve ◽  
Human Subjects ◽  
Bright Light ◽  
Phase Response ◽  
Light Pulses

Notizen: Weak and Strong Phase Shifting in the Activity Rhythm of Leucophaea maderae (Blaberidae)after Light Pulses of High Intensity

1977 ◽  
Vol 32 (5-6) ◽  
pp. 464-465 ◽  
Author(s):  
Gottfried Wiedenmann
Keyword(s):  
High Intensity ◽  
Response Curve ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Phase Response ◽  
Strong Phase ◽  
Light Pulses ◽  
Leucophaea Maderae ◽  
Running Activity ◽  
High Intensity Light

Abstract In the running activity of the cockroach Leucophaea maderae a strong phase response curve is found when using high intensity light pulses (80 000 lx and about 12 hours duration). The phase response curve has an unsymmetric shape: delays are larger than advances. The phase jump lies about 2 hours after subjective midnight.

Administering triazolam on a circadian basis entrains the activity rhythm of hamsters

1989 ◽  
Vol 256 (3) ◽  
pp. R639-R645
Author(s):  
O. Van Reeth ◽  
F. W. Turek
Keyword(s):  
Response Curve ◽  
Wheel Running ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Phase Relationship ◽  
Phase Shifts ◽  
Phase Response ◽  
Light Pulses ◽  
Circadian Time ◽  
Free Running

A single injection of the short-acting benzodiazepine, triazolam, can induce permanent phase shifts in the circadian rhythm of locomotor activity in free-running hamsters, with the direction and magnitude of the phase shifts being dependent on the circadian time of treatment. The shape of the "phase-response curve" to triazolam injections is totally different from that for light pulses. These findings raise the possibility that repeated injections of triazolam on a circadian basis might be capable of entraining the circadian pacemaker underlying the activity rhythm of hamsters and that the entrainment pattern might differ from that observed in animals entrained to light pulses. To test this hypothesis, blind hamsters received intraperitoneal injections of triazolam (or vehicle) every 23.34, 23.72, 24.00 or 24.66 h for 19-20 days, and the effect of these injections on the period of the rhythm of wheel-running behavior was determined during and after treatment. Repeated injections of 0.1 mg triazolam at these time intervals resulted in the entrainment of the activity rhythm in 36 of 40 animals, whereas 0 of 40 animals entrained to vehicle injections. Importantly, the phase relationship between triazolam injections and the circadian activity rhythm was dependent on the period of drug treatment and could be predicted from the phase-response curve to single injections of triazolam. These phase relationships are dramatically different from those observed between the activity rhythm and 1-h light pulses presented at similar circadian intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Entrainment of the circadian rhythm from the eye of Aplysia: role of serotonin

1982 ◽  
Vol 242 (3) ◽  
pp. R326-R332
Author(s):  
G. Corrent ◽  
A. Eskin ◽  
I. Kay
Keyword(s):  
Circadian Rhythm ◽  
Phase Shift ◽  
Transmitter Release ◽  
Response Curve ◽  
Phase Shifts ◽  
Phase Response ◽  
Phase Shifting ◽  
Response Curves ◽  
Light Pulses

The finding that serotonin (5-HT) treatments as short as 1.5 h in duration produce phase shifts in a circadian rhythm from the isolated eye of Aplysia suggested that release of 5-HT was part of an ocular entrainment pathway. Since light cycles entrain this rhythm, we compared phase shifting by 5-HT and by light. The similarity in the shapes of the phase-response curves for 5-HT and light pulses indicates that 5-HT treatments are capable of entraining the rhythm. Also, "skeleton" 5-HT treatments phase shift as well as continuous 5-HT treatments. However, 5-HT does not appear to mediate the phase shifts produced by light, since 1) treatments that should block transmitter release do not change the phase shifts produced by light pulses; 2) the response curves of 5-HT and light pulses are displaced by 12 h relative to one another on the phase axis of the response curve; and 3) light-induced phase shifts are apparent almost immediately, whereas 5-HT-induced phase shifts become evident only about 24 h after 5-HT treatment. The eye appears to contain two independent entrainment pathways, one for light and one utilizing 5-HT.

Phase-response curve to 1-hour light pulses for the marsupial, Dasyuroides byrnei

1989 ◽  
Vol 46 (4) ◽  
pp. 667-670 ◽  
Author(s):  
Gerard A. Kennedy ◽  
Stuart M. Armstrong ◽  
Grahame J. Coleman
Keyword(s):  
Response Curve ◽  
Phase Response Curve ◽  
Phase Response ◽  
Light Pulses

scholarly journals Effect of Phase Response Curve Skewness on Synchronization of Electrically Coupled Neuronal Oscillators

2013 ◽  
Vol 25 (10) ◽  
pp. 2545-2610 ◽  
Author(s):  
Ramana Dodla ◽  
Charles J. Wilson
Keyword(s):  
Linear Model ◽  
Response Curve ◽  
Time Course ◽  
Phase Response Curve ◽  
Piecewise Linear ◽  
Time Parameter ◽  
Phase Response ◽  
Single Time ◽  
Piecewise Linear Model ◽  
Neuronal Oscillators

We investigate why electrically coupled neuronal oscillators synchronize or fail to synchronize using the theory of weakly coupled oscillators. Stability of synchrony and antisynchrony is predicted analytically and verified using numerical bifurcation diagrams. The shape of the phase response curve (PRC), the shape of the voltage time course, and the frequency of spiking are freely varied to map out regions of parameter spaces that hold stable solutions. We find that type 1 and type 2 PRCs can hold both synchronous and antisynchronous solutions, but the shape of the PRC and the voltage determine the extent of their stability. This is achieved by introducing a five-piecewise linear model to the PRC and a three-piecewise linear model to the voltage time course, and then analyzing the resultant eigenvalue equations that determine the stability of the phase-locked solutions. A single time parameter defines the skewness of the PRC, and another single time parameter defines the spike width and frequency. Our approach gives a comprehensive picture of the relation of the PRC shape, voltage time course, and stability of the resultant synchronous and antisynchronous solutions.

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