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Circadian Rhythms and Gene Regulation02:19

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The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
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Related Experiment Video

Updated: Jun 25, 2026

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World
10:16

Human Circadian Phenotyping and Diurnal Performance Testing in the Real World

Published on: April 7, 2020

[Measuring circadian rhythm].

E Haffen1

  • 1Service de Psychiatrie de l'Adulte - Pr Daniel Sechter, Laboratoire de Neurosciences Cliniques et Intégratives (EA481), Université de Franche-Comté, place Leclerc, 25030 Besançon cedex. emmanuel.haffen@univ-fcomte.fr

L'Encephale
|March 10, 2009
PubMed
Summary
This summary is machine-generated.

Circadian rhythms, biological cycles around 24 hours, are measured using mathematical models. Understanding their stability is key to uncovering mechanisms behind psychiatric diseases.

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Area of Science:

  • Chronobiology
  • Physiology
  • Biomathematics

Context:

  • Circadian rhythms are endogenous 24-hour cycles influencing biological processes.
  • Environmental factors can synchronize or shift these rhythms.
  • Accurate measurement requires protocols to isolate internal rhythms from external influences.

Purpose:

  • To outline the parameters of circadian rhythms, including amplitude, period, phase, and mesor.
  • To detail various methods for measuring circadian rhythms, such as sleep diaries, actimetry, and hormone assays.
  • To emphasize the importance of understanding circadian rhythm stability for psychiatric research.

Summary:

  • Circadian rhythms are approximately 24-hour biological cycles regulated by an internal clock, influenced by environmental cues.
  • Measurement involves mathematical modeling to determine parameters like amplitude, period, and phase.
  • Key markers include sleep-wake cycles, rest-activity patterns, body temperature, melatonin, cortisol, and clock gene activity.

Impact:

  • Improved understanding of circadian rhythm parameters, especially stability, is crucial.
  • This knowledge aids in elucidating pathophysiological mechanisms in psychiatric disorders.
  • Accurate assessment of circadian rhythms can inform diagnostic and therapeutic strategies.