zeitgeber

The length of the dormancy appears to depend on environmental factors, with the most likely zeitgeber being photoperiod.

Such zeitgeber disruptions can also lead to decreased cognitive performance, negative mood, and in some cases, episodes of mental illness.

In circadian physiology, ψ represents the phase relationship between a zeitgeber and a biological rhythm.

Differentiating between zeitgeber disturbances that lead to depression and those that lead to manic episodes has proven difficult.

Plasma DLMO10 zeitgeber time 14: The therapeutic window for phase-delayed winter depressives treated with melatonin.

Since the environmental rhythm is giving a time-cue to the organism it is called a zeitgeber (from the German, Zeit - time; geber - to give).

A zeitgeber is any external or environmental cue that entrains, or synchronizes, an organism's biological rhythms to the earth's 24-hour light/dark cycle and 12 month cycle.

The term "zeitgeber" (German for "time giver" or "synchronizer") was first used by Jürgen Aschoff, one of the founders of the field of chronobiology.

Samples were then taken in darkness at 6 time points referenced to the normal LD cycle in which they had been maintained (referred to as Zeitgeber Time).

He observed in the period of spore production (conidia bands) the phenomenon of masking, an unexpected effect on circadian entrainment due to a particular zeitgeber (such as light or temperature).

Following up on his temperature studies, he found that a mammalian species can entrain to a temperature cycle, but that temperature is a weak Zeitgeber compared to a light-dark cycle.

In 1960, Aschoff coined the term Zeitgeber (from German for "time giver" or "synchronizer") to refer to external, environmental cues that synchronize an endogenous oscillator to the environmental cycle.