Nav: Home

Brain activity intensity drives need for sleep

September 16, 2019

The intensity of brain activity during the day, notwithstanding how long we've been awake, appears to increase our need for sleep, according to a new UCL study in zebrafish.

The research, published in Neuron, found a gene that responds to brain activity in order to coordinate the need for sleep. It helps shed new light on how sleep is regulated in the brain.

"There are two systems regulating sleep: the circadian and homeostatic systems. We understand the circadian system pretty well - our built-in 24-hour clock that times our biological rhythms, including sleep cycles, and we know where in the brain this rhythm is generated," explained lead author Dr Jason Rihel (UCL Cell & Developmental Biology).

"But the homeostatic system, which causes us to feel increasingly tired after a very long day or sleepless night, is not well understood. What we've found is that it appears to be driven not just by how long you've been awake for, but how intensive your brain activity has been since you last slept."

To understand what processes in the brain drive homeostatic sleep regulation - independent of time of day - the research team studied zebrafish larvae.

Zebrafish are commonly used in biomedical research, partly due to their near-transparent bodies that facilitate imaging, in addition to similarities to humans such as sleeping every night.

The researchers facilitated an increase in brain activity of the zebrafish using various stimulants including caffeine.

Those zebrafish which had drug-induced increased brain activity slept for longer after the drugs had worn off, confirming that the increase in brain activity contributed to a greater need for sleep.

The researchers found that one specific area of the zebrafish brain was central to the effect on sleep pressure: a brain area that is comparable to a human brain area found in the hypothalamus, known to be active during sleep. In the zebrafish brain area, one specific brain signalling molecule called galanin was particularly active during recovery sleep, but did not play as big a role in regular overnight sleep.

To confirm that the drug-induced findings were relevant to actual sleep deprivation, the researchers conducted a test where they kept the young zebrafish awake all night on a 'treadmill' where the fish were shown moving stripes - by imitating fast-flowing water, this gives the fish the impression that they need to keep swimming. The zebrafish that were kept awake slept more the next day, and their brains showed an increase in galanin activity during recovery sleep.

The findings suggest that galanin neurons may be tracking total brain activity, but further research is needed to clarify how they detect what's going on across the whole brain.

The researchers say their finding that excess brain activity can increase the need for sleep might explain why people often feel exhausted after a seizure.

"Our findings may also shed light on how some animals can avoid sleep under certain conditions such as starvation or mating season - it may be that their brains are able to minimise brain activity to limit the need for sleep," said the study's first author, Dr Sabine Reichert (UCL Cell & Developmental Biology).

The researchers say that by discovering a gene that plays a central role in homeostatic sleep regulation, their findings may help to understand sleep disorders and conditions that impair sleep, such as Alzheimer's disease.

"We may have identified a good drug target for sleep disorders, as it may be possible to develop therapies that act on galanin," added Dr Reichert.
-end-
The study was supported by Wellcome and the European Research Council.

University College London

Related Science Articles:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.
Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.
Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.
Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.
World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.
PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.
Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.
Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.
Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.
More Science News and Science Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.