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

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.

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.

More on a human phase‐response curve (PRC) to bright light

1990 ◽  
Vol 21 (3) ◽  
pp. 222-224 ◽  
Author(s):  
D.S. Minors ◽  
J.M. Waterhouse ◽  
Anna Wirz‐Justice
Keyword(s):  
Response Curve ◽  
Phase Response Curve ◽  
Bright Light ◽  
Phase Response

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)

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

Synchronization of two coupled pacemaker cells based on the phase response curve

2009 ◽  
Vol 4 (1) ◽  
pp. 57-66
Author(s):  
Hossein Gholizade-Narm ◽  
Asad Azemi ◽  
Morteza Khademi ◽  
Masoud Karimi-Ghartemani
Keyword(s):  
Response Curve ◽  
Phase Response Curve ◽  
Phase Response ◽  
Pacemaker Cells
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