#aschoff

The effect of light intensity on the free-running period (a.k.a., the spontaneous frequency) of circadian rhythms under constant light for several animals and plants.  Aschoff’s rules were based on such comparisons across phyla.  The figure is taken from Aschoff’s chapter on “Exogenous and Endogenous Components” from the Cold Spring Harbor Symposium on Quantitative Biology on Biological Clocks in 1960: http://library.cshl.edu/symposia/1960/contents.html

Activity records of five chaffinches held under constant light and temperature. The bird shown in panel I (top) was exposed to a light intensity of 5 lux. The birds shown in panels II-V were exposed to an order of magnitude dimmer light. Here Aschoff’s focus is on the relationships between the free-running period (τ) and the two major components of the actogram, activity (α) and rest (ρ). Quoting Aschoff: “It may be asked whether, under constant conditions, the variability of the whole period τ is simply the summation of the variabilities of α and ρ or whether τ is more or less stable than its two components.” Aschoff was also working out the best way to assess the precision of τ. The figure is taken from chapter one of the book “Biochronometry,” edited by Michael Menaker, which is a record of the proceedings of a symposium held at Friday Harbor, Washington in September 1969, published by the National Academy of Sciences.

Human physiological and behavioral rhythms under temporal isolation recorded in an underground bunker consisting of a “comfortable bed-sitting room” attached to a shower and small kitchen. Circadian changes in urination, core body temperature, and sleep and wakefulness are apparent. The subject in this case was the author J. Aschoff.  From  J. Aschoff (1965) Circadian Rhythms in Man. Science. Vol. 148, pp. 1427-1432

haha. :)

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