Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

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,...
Circadian Rhythms and Gene Regulation02:19

Circadian Rhythms and Gene Regulation

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,...
Biological Clocks and Seasonal Responses02:45

Biological Clocks and Seasonal Responses

The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response01:15

Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response

Circadian rhythms are cyclic changes that are crucial in plasma drug concentrations. Various standard circadian parameters, including core body temperature, heart rate, and other cardiovascular factors, directly impact disease states and the therapeutic response to drug therapy.
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
Understanding Sleep01:11

Understanding Sleep

Sleep, an essential biological state, involves significant reductions in physical activity, sensory awareness, and interaction with the environment. This complex physiological process is primarily regulated by specific brain regions, notably the hypothalamus and pons, which govern the sleep-wake cycle or circadian rhythm.
The circadian rhythm, a nearly 24-hour cycle, is deeply influenced by environmental light cues. Light exposure directly affects the hypothalamus, which in turn regulates...
Personality Theory by Eysenck and Eysenck01:29

Personality Theory by Eysenck and Eysenck

Hans and Sybil Eysenck developed a widely recognized theory of personality, which emphasizes the role of temperament and genetically based differences in shaping individual traits. Their theory posits that biological factors primarily determine personality and can be understood through two main dimensions: extroversion/introversion and neuroticism/stability.
In the extroversion/introversion dimension, highly extroverted people are sociable, outgoing, and easily connect with others. In contrast,...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Early but not late time-restricted eating improves an actigraphy-estimated sleep quality in women with overweight or obesity: secondary analysis of the crossover ChronoFast trial.

Frontiers in nutrition·2026
Same author

Investigating the risk of obesity in European night shift workers: a study protocol for cross-sectional and mechanistic studies in the SHIFT2HEALTH Project.

Obesity facts·2026
Same author

Remodeling of human diurnal adipose tissue transcriptome by the composition of morning and afternoon meals.

Food research international (Ottawa, Ont.)·2026
Same author

A Lentiviral Fluorescent Reporter to Study Circadian Rhythms in Single Cells.

Journal of biological rhythms·2026
Same author

HairTime: A noninvasive assay for estimating circadian phase from a single hair sample.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Circadian rhythm heterogeneity modulates drug response variations in neuroblastoma models.

Cell reports·2026
Same journal

Analysis of strength degradation of coal and rock masses and stability of mined areas under long term immersion environment.

PloS one·2026
Same journal

Biogenic Silver-Selenium nanocomposite with anticancer activity and potent efficacy against vancomycin-resistant Staphylococcus aureus.

PloS one·2026
Same journal

Preparation and physicochemical characterization of a biodegradable chitosan/carboxymethyl cellulose hydrogel synthesized in NaOH/urea medium.

PloS one·2026
Same journal

Action-guilt, survivor-guilt, and depression in combat-related PTSD.

PloS one·2026
Same journal

Explainable machine learning for predicting activities of daily living at discharge in stroke patients: A retrospective study using SHAP interpretability.

PloS one·2026
Same journal

Deep learning based two-way feature depiction model for brain tumor detection.

PloS one·2026
See all related articles

Related Experiment Video

Updated: May 12, 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

Human chronotypes from a theoretical perspective.

Adrián E Granada1, Grigory Bordyugov, Achim Kramer

  • 1Institute for Theoretical Biology, Humboldt University, Berlin, Germany.

Plos One
|April 2, 2013
PubMed
Summary
This summary is machine-generated.

This study reveals how internal body clocks synchronize with external cues (Zeitgebers). A key finding, the "180° rule," shows phase shifts are predictable, explaining diverse human chronotypes.

More Related Videos

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
08:36

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments

Published on: August 8, 2019

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila
09:09

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila

Published on: January 13, 2014

Related Experiment Videos

Last Updated: May 12, 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

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments
08:36

Collecting Sleep, Circadian, Fatigue, and Performance Data in Complex Operational Environments

Published on: August 8, 2019

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila
09:09

Design and Analysis of Temperature Preference Behavior and its Circadian Rhythm in Drosophila

Published on: January 13, 2014

Area of Science:

  • Chronobiology
  • Systems Biology
  • Mathematical Biology

Background:

  • Organisms possess endogenous circadian timing systems to synchronize with environmental cycles.
  • External cues, known as Zeitgebers, entrain these internal biological clocks.
  • Entrainment involves the clock adopting a fixed phase relationship (ψ) to the Zeitgeber.

Purpose of the Study:

  • To systematically investigate how entrainment phase (ψ) is influenced by properties of both the biological clock and the Zeitgeber.
  • To establish quantitative relationships between entrainment phase, Zeitgeber properties, and clock characteristics.
  • To explore the implications of these findings for understanding biological rhythms and chronotypes.

Main Methods:

  • Utilized numerical simulations of amplitude-phase models for circadian rhythms.
  • Integrated predictions from analytically tractable models.
  • Derived mathematical relationships governing the phase of entrainment.

Main Results:

  • Established a core finding termed the "180° rule," describing the predictable variation of entrainment phase (ψ) within the entrainment range.
  • Demonstrated that the phase of entrainment (ψ) is dependent on the mismatch between endogenous and Zeitgeber periods, Zeitgeber strength, and the range of entrainment.
  • Showed that clocks with a narrow entrainment range ("strong oscillators") exhibit flexible entrainment phases.

Conclusions:

  • The
  • 180° rule
  • provides a framework for understanding how biological clocks synchronize with external cues.
  • The high sensitivity of entrainment phase in strong oscillators is proposed as a contributing factor to the diversity of human chronotypes.
  • This research offers insights into the fundamental mechanisms of circadian entrainment and its biological consequences.