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Recently, ultradian rhythms of arousal lasting approximately 4 hours were attributed to the dopaminergic system in mammals. [5] When the dopaminergic system is perturbed either by use of drugs or by genetic disruption, these 4-hour rhythms can lengthen significantly into the infradian (> 24 h) range, sometimes even lasting for days (> 110 h ...
Empirically, it is an ultradian rhythm of approximately 90 minutes (80–120 minutes [2]) characterized by different levels of excitement and rest. The cycle is mediated by the human biological clock .
Overview, including some physiological parameters, of the human circadian rhythm ("biological clock"). Chronobiology is a field of biology that examines timing processes, including periodic (cyclic) phenomena in living organisms, such as their adaptation to solar- and lunar-related rhythms. [1] These cycles are known as biological rhythms.
Ultradian rhythms, which are cycles shorter than 24 hours, such as the 90-minute REM cycle, the 4-hour nasal cycle, or the 3-hour cycle of growth hormone production. Tidal rhythms, commonly observed in marine life, which follow the roughly 12.4-hour transition from high to low tide and back. Lunar rhythms, which follow the lunar month (29.5 ...
Kleitman and others following have referred to this rhythm as the basic rest–activity cycle, of which the "sleep cycle" would be a manifestation. [ 14 ] [ 19 ] A difficulty for this theory is the fact that a long non-REM phase almost always precedes REM, regardless of when in the cycle a person falls asleep.
"The rhythm of a game of basketball emerges from the rhythm of individuals, the rhythm among team members, and the rhythmic contrasts between opposing teams". [6] Although the exact oscillatory pattern that modulates different sports has not been found, there have been studies done to show a correlation between athletic performance and ...
The first published usage of the term "phase response curve" was in 1960 by Patricia DeCoursey. The "daily" activity rhythms of her flying squirrels, kept in constant darkness, responded to pulses of light exposure. The response varied according to the time of day – that is, the animals' subjective "day" – when light was administered.
After further breeding these mutant hamsters, he noticed that homozygous mutants had a 20 hour period of daily activity rhythms and heterozygous mutants had a 22 hours period. [3] In circadian biology, tau (τ), denoted the duration of a rhythm in an organism, so a circadian rhythm has a tau value near 24 hours. Given the differences in period ...