Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Biological clock more influenced by temperature than light


’The brain’s Timex’

Getting over jet lag may be as simple as changing the temperature --your brain temperature, that is.

That’s a theory proposed by Erik Herzog, Ph.D. assistant professor of biology in Arts & Sciences at Washington University in St. Louis. Herzog has found that the biological clocks of rats and mice respond directly to temperature changes.

Biological clocks, which drive circadian rhythms, are found in almost every living organism. In mammals, including humans, these clocks are responsible for 24-hour cycles in alertness and hormone levels, for instance. The control panel for these daily rhythms is the suprachiasmatic nucleus (SCN), otherwise known as "the brain’s Timex." The SCN, located above the roof of the mouth in the hypothalamus, is normally synchronized to local time by light signals carried down the optic nerves. Herzog worked directly with mice SCN cells located in vitro, grown in a dish.

"We found that we can rapidly change the phase of the pacemaker. We can shift its timing to a new time zone," said Herzog. "This paper shows for the first time that we can take control of the clock in a dish. We can tell it what time we want it to think it is."

Herzog’s findings were recently published in the Journal of Neurophysiology.. His work was funded by the National Institute of Mental Health.

The findings have significant future implications. If brain temperature can be controlled, travellers might never have to deal with jet lag again. Shifting to a new time zone might be accomplished with relative ease.

Herzog says that brain temperature is relatively immune to environmental temperature, but can be affected by bursts of physical activity, fever, nursing, or a dose of aspirin or melatonin, a drug already used to lessen the effects of jet lag.

In his study, Herzog first needed to establish that the SCN would function normally over a wide range of constant temperatures. He tested the cells in a range from 24 C to 370C. With each change in temperature, the SCN cells continued to operate like clockwork.

"Just like a good watch, the SCN needs to be accurate over a range of temperatures. Your wristwatch would be of no use to you if it sped up every time it became warm. Biological clocks work the same way. Amazingly enough, the SCN can oscillate over a wide range of temperatures."

But Herzog was keeping the cells in constant temperature and, he noted, this is not the way your brain really works. Normally, brain temperature fluctuates by about 1.50C every day. Temperature is at its minimum at daybreak, at its maximum during mid-day. This fluctuation exists even in the absence of any environmental cues, such as light and dark. "If you lived in a cave," Herzog notes, "you’d still have a daily rhythm in temperature.

"So we asked the question if that cycling of temperature, if that 1.50C, would have any effect on the pacemaking of the SCN." The answer was a resounding yes.

Herzog simply warmed the isolated SCN during the day and cooled it during the night, reversing the rat’s normal daily fluctuation. He found that he could change the time at which the SCN "peaked."

"It shows that the SCN synchronized to the temperature cycle. The temperature cycle entrained it. We fooled the clock by giving it a novel daily schedule, saying ’This isn’t the end of the day. This is morning.’"

Herzog’s research also sought to disprove the notion put forth in 1998 that shining light on the backs of the knees would be enough to adjust circadian rhythm to a new time zone.

The idea was that by sensing light at the appropriate time people can become synchronized to a new time zone. So Herzog wanted to know: Does the SCN by itself have any light sensitivity?

"We took the SCN out of the animal, put it in a dish, and exposed it to light at night and dark during the day. We asked: does it synchronize to that light-dark schedule? The answer was no." The human biological clock requires the signals from eyes to synchronize to the local light cycle.

Taken together, Herzog’s findings indicate that, to avoid jet lag on our next trip to Paris, we should be sure to see the dawn while keeping our brains cool. Future work might lead to a better understanding of what changes brain temperature and why.

Tony Fitzpatrick | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht Novel mechanisms of action discovered for the skin cancer medication Imiquimod
21.10.2016 | Technische Universität München

nachricht Second research flight into zero gravity
21.10.2016 | Universität Zürich

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>