Subscribe to our free daily newsletters
. Earth Science News .




Subscribe to our free daily newsletters



ABOUT US
The neural relationship between light and sleep
by Staff Writers
Pasadena CA (SPX) Jun 27, 2017


illustration only

Humans are diurnal animals, meaning that we usually sleep at night and are awake during the day, due at least in part to light or the lack thereof. Light is known to affect sleep indirectly by entraining - modifying the length of - our circadian rhythms and also rapidly and directly due to a phenomenon known as masking.

But while a great deal is known about how light affects circadian rhythms, little is known about the direct effects of light on sleep: Why do we tend to wake up if the lights are flipped on in the middle of the night? Why does darkness make us sleepy?

Caltech researchers in the laboratory of Professor of Biology David Prober say they have discovered at least part of the answer: a specific protein in the brain that responds to light and darkness to set the correct balance between sleep and wakefulness.

Their work is described in a paper appearing online in the journal Neuron on June 22.

"Researchers had previously identified the photoreceptors in the eye that are required for the direct effect of light on wakefulness and sleep," says Prober. "But we wanted to know how the brain uses this visual information to affect sleep."

The Prober laboratory uses zebrafish as a model organism for studying sleep. The animals are optically transparent, allowing for noninvasive imaging of their neurons; they also have a diurnal sleep/wake pattern like that of humans. To investigate how their sleep responds to light, Wendy Chen, a former graduate student in Prober's lab, led studies examining a particular protein in the zebrafish brain called prokineticin 2 (Prok2).

Chen genetically engineered zebrafish to overexpress Prok2, resulting in an abundance of the protein. She found that in contrast to normal zebrafish, these animals were more likely to fall asleep during the day and to wake up at night. Surprisingly, the effects did not depend on the engineered fish's normal circadian sleep/wake cycle but rather depended only on whether the lights were on or off in their environment. These observations suggest that an excess of Prok2 suppresses both the usual awakening effect of light and the sedating effect of darkness.

Chen then generated zebrafish with mutated forms of Prok2 and its receptor, and observed light-dependent sleep defects in these animals. For example, Chen found that zebrafish with a mutated Prok2 receptor were more active when the lights were on and less active when the lights were off, the opposite of what she had observed in animals that overexpressed Prok2 and had functional Prok2 receptors.

"Though diurnal animals such as zebrafish spend most of their time asleep at night and awake during the day, they also take naps during the day and occasionally wake up at night, similar to many humans," Prober says. "Our study's results suggest that levels of Prok2 play a critical role in setting the correct balance between sleep and wakefulness during both the day and the night."

Next, the researchers wanted to know how Prok2 was modulating light's effects on sleep. To answer this question, they decided to examine whether other proteins in the brain that are known to affect sleep were required for the effects of Prok2 on sleep behavior.

They found that the sedating effect of Prok2 overexpression in the presence of light requires galanin, a known sleep-promoting protein.

They also found that Prok2 overexpression increased the level of galanin expression in the anterior hypothalamus, a key sleep-promoting center in the brain. But in animals that were engineered to lack galanin, overexpression of Prok2 did not increase sleep.

These findings provide the first insights into how light may interact with the brain to affect sleep and provide a basis for scientists to begin exploring the genes and neurons that underlie the phenomenon. However, further work is needed to fully explain how light and dark directly affect sleeping and waking, and to determine whether Prok2 has a similar function in humans. If it does, this work might eventually lead to new sleep- and wake-promoting drugs.

Research Report: "Light-dependent regulation of sleep/wake states by prokineticin 2 in zebrafish."

ABOUT US
World population to reach 9.8 bln in 2050, UN says
United Nations, United States (AFP) June 21, 2017
The world's current population of 7.6 billion will balloon to 9.8 billion in 2050, with India's numbers to surpass China's in just seven years, a UN report said Wednesday. Nigeria will overtake the United States by 2050 to become the third most populous country in the world, according to the figures by the UN Department of Economic and Social Affairs. "With roughly 83 million people bein ... read more

Related Links
California Institute of Technology
All About Human Beings and How We Got To Be Here


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

ABOUT US
Kurdish designers bring fight with IS to Paris catwalk

Hopes dim in search for 93 missing in China landslide

Hopes dim in search for 118 buried by China landslide

FLIR awarded $17.9 million contract for Coast Guard surveillance systems

ABOUT US
A more sustainable way to refine metals

NREL-led research effort creates new alloys, phase diagram

Scientists develop molecular code for melanin-like materials

Beetles spark development of color-changing nanoparticles for commercial use

ABOUT US
Wave beams mix and stir the ocean to create climate

Algae The final frontier

Great Barrier Reef a $42 billion asset 'too big to fail': study

Amazonia's future will be jeopardized by dams

ABOUT US
Widespread snowmelt in West Antarctica during unusually warm summer

Wet and stormy weather lashed California coast... 8,200 years ago

Bolivian glacier samples ready for global ice archives

Antarctic researchers take icy plunge to mark solstice

ABOUT US
Bubbling Chinese market centre-stage at world wine fest

China opens gates to US beef imports

Growers at Bordeaux winefest unite against climate change

China 'backyard' pig farmers squeezed as sector scales up

ABOUT US
Heavy rains have killed 15 in Ivory Coast

One killed as Storm Cindy makes landfall in southern US

6.8-magnitude quake hits Guatemala, second in eight days: USGS

Flash flood warning as Tropical Storm Cindy heads towards US

ABOUT US
Mali relaunches beleagured peace process

Clashes erupt in C. Africa a day after peace deal

Mali ex-rebels reject national charter on peace deal anniversary; Dozens killedw/l

C. Africa govt inks peace deal with rebel groups

ABOUT US
New research suggests problematic memories could be deleted

World population to reach 9.8 bln in 2050, UN says

Chinese gays hear wedding bells as Taiwan move fuels hope

Too much brain activity may contribute to memory, attention impairments




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement