Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Circadian Rhythms and Gene Regulation

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 Regulation

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 Responses

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.

Functional Brain Systems: Reticular Formation

Functional Brain Systems: Reticular Formation

The reticular formation is a complex network of gray and white matter located within the brainstem extending from the medulla to the midbrain.
Within the reticular formation, there are several distinct nuclei that can be classified into three broad categories. The Raphe nuclei are located along the midline of the brainstem. They are primarily known for their role in synthesizing and releasing serotonin, a neurotransmitter involved in regulating mood, appetite, sleep, and circadian rhythms. The...

Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response

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...

The Pineal Gland

The Pineal Gland

The pineal gland, a diminutive endocrine structure named for its pinecone-shaped appearance, is situated atop the third ventricle within the diencephalon region of the forebrain. This gland, composed of secretory cells known as pinealocytes arranged in compact cords and clusters around dense particles of calcium salts, plays a pivotal role in hormonal regulation.
The primary secretion of the pineal gland is the hormone melatonin, derived from serotonin. The concentration of melatonin in the...

You might also read

Related Articles

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

Sort by

Same author

A hypothalamic circuit for circadian regulation of corticosterone secretion.

Nature communications·2026

Same author

Shunting for Idiopathic Normal-Pressure Hydrocephalus.

The New England journal of medicine·2026

Same author

Time to Reconsider the Value of Shunting Procedures for "Idiopathic Normal Pressure Hydrocephalus".

Annals of neurology·2026

Same author

Circadian rhythms in sexual behavior and their influence on reproductive outcomes in mice.

bioRxiv : the preprint server for biology·2025

Same author

A brain-body perspective on thermoregulatory adaptation.

Current biology : CB·2025

Same author

Preoptic EP3R neurons constitute a two-way switch for fever and torpor.

Nature·2025

Search research articles

Related Experiment Video

Updated: May 11, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Published on: November 11, 2016

The central circadian timing system.

Clifford B Saper¹

¹Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, United States.

Current Opinion in Neurobiology

|May 28, 2013

Summary

The suprachiasmatic nucleus (SCN) synchronizes body clocks, but other cells also use genetic clocks. This review examines how the SCN maintains circadian rhythms and when other clocks might take over, such as during restricted feeding.

More Related Videos

Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents

Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents

Published on: January 24, 2013

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter

Published on: September 17, 2016

Related Experiment Videos

Last Updated: May 11, 2026

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Parallel Measurement of Circadian Clock Gene Expression and Hormone Secretion in Human Primary Cell Cultures

Published on: November 11, 2016

Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents

Recording and Analysis of Circadian Rhythms in Running-wheel Activity in Rodents

Published on: January 24, 2013

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter

Published on: September 17, 2016

Area of Science:

Neuroscience
Chronobiology
Molecular Biology

Background:

The suprachiasmatic nucleus (SCN) is recognized as the master biological clock in the brain.
The SCN utilizes a genetic clock, based on transcriptional-translational loops, for timekeeping.
Recent findings indicate peripheral cells also possess similar genetic clocks, prompting questions about SCN synchronization.

Purpose of the Study:

To review the evidence supporting the SCN's role in orchestrating circadian rhythms across the body.
To explore the neural circuitry involved in the SCN's synchronization of peripheral clocks.
To investigate the potential for peripheral clocks to override SCN control under specific conditions, like restricted feeding.

Main Methods:

Literature review and synthesis of existing research on circadian rhythms.
Analysis of studies investigating the SCN's necessity for maintaining biological rhythms.
Examination of evidence related to the circadian timing system and its circuitry.

Main Results:

The SCN is crucial for synchronizing diverse cellular clocks throughout the organism.
Specific neural pathways facilitate the SCN's control over peripheral circadian oscillators.
Evidence suggests peripheral clocks can influence or dominate physiological and behavioral rhythms.

Conclusions:

The SCN acts as a central coordinator for the body's circadian timing system.
Understanding the interplay between the SCN and peripheral clocks is key to comprehending overall biological rhythm regulation.
Dietary interventions, such as restricted feeding, may alter the hierarchical control of circadian rhythms, allowing peripheral clocks a more prominent role.