Science Current Events | Science News | Brightsurf.com
 

Losing sleep undoes the rejuvenating effects new learning has on the brain

January 09, 2006
As the pace of life quickens and it becomes harder to balance home and work, many people meet their obligations by getting less sleep.

But sleep deprivation impairs spatial learning - including remembering how to get to a new destination. And now scientists are beginning to understand how that happens: Learning spatial tasks increases the production of new cells in an area of the brain involved with spatial memory called the hippocampus. Sleep plays a part in helping those new brain cells survive.

A team of researchers from the University of California and Stanford University found that sleep-restricted rats had a harder time remembering a path through a maze compared to their rested counterparts. And unlike the rats that got enough sleep, the sleep-restricted rats showed reduced survival rate of new hippocampus cells.

The researchers used sleep-restricted rats rather than sleep-deprived rats to more closely mimic the common human experience of inadequate sleep during the work week, said lead investigator Ilana Hairston of both the University of California, Berkeley, and Stanford University. The paper, "Sleep restriction suppresses neurogenesis induced by hippocampus-dependent learning," appears in the Journal of Neurophysiology published by the American Physiological Society. Stanford researchers Milton T.M. Little, Michael D. Scanlon, Monique T. Barakat, Theo D. Palmer, Robert M. Sapolsky, and H. Craig Heller co-authored the paper.

Learning appears to rejuvenate the brain

Scientists already know - and most of us can confirm from firsthand experience - that lack of sleep impairs cognitive function. Sleep-restricted individuals have a shorter attention span, impaired memory, and a longer reaction time. "Sleep is necessary for general health, but it now appears that the brain needs sleep more than any other part of the body," Hairston said.

Previous studies have shown that the hippocampus is important for spatial learning. "The hippocampus also has the unique ability to generate new brain cells throughout life, a process called 'neurogenesis,'" Hairston noted. "When animals learn a task that requires the hippocampus, the rate of neurogenesis increases. This suggests that learning itself rejuvenates the brain."

Knowing that spatial learning triggers production of new brain cells in the hippocampus, Hairston and her team wanted to find out whether restricting sleep during a spatial learning task would affect new cell production in the hippocampus.

The experiment: swimming to the exit platform

The researchers trained rats on one of two tasks using a water maze - a plastic pool about six feet in circumference and two feet deep. Rats were placed in the water and had to swim to the exit platform.

One group could not see the platform, which was placed underwater, and had to form a "mental map" of the maze - a spatial memory task that is hippocampus-dependent - to quickly reach the exit.

The second group could see and smell the exit platform, which had a citrus odor. The researchers moved the platform every fourth trial, requiring the animal to rely on its senses, not on memory, to find it. This task did not engage the hippocampus because the rat did not need a mental map of the pool to reach the platform, Hairston explained.

Fewer brain cells for the weary

At the end of each training session, half the animals in each group were kept awake for six hours by being presented novel stimuli that kept them interested and awake. The other half were returned to their cages and allowed to sleep. After six hours, the sleep-restricted rats were allowed to sleep for the remainder of the day until the next session, 18 hours later.

Rested animals that had to rely on memory to find the goal showed increased neurogenesis in the hippocampus compared with animals that could use sight and smell. That made sense, because the task that relied on memory involved the hippocampus, while the other did not.

However, the sleep-restricted rats that had to rely on memory to find the goal showed no increased neurogenesis, unlike their rested counterparts. This means that lack of sleep undoes the cell rejuvenation benefit that would normally come from the task, the researchers noted.

Sleep restriction prompts use of a secondary strategy

On the other hand, the sleep-restricted rats that were required to locate the platform using visual and odor cues did better on the task than their rested counterparts. This was an unexpected finding.

Hairston et al. believe it is because the rested group tried to rely on memory to find the platform, generally a better strategy to reach a goal you have reached before. But in this case, where the researchers moved the goal every fourth trial, using the visual and odor cues was a better strategy. It appears that the sleep-restricted rats changed their strategy to compensate for their lack of sleep - and it worked.

"The sleep-restricted rats in this group actually did better because the lack of sleep interfered with their ability to memorize the maze - forcing them to rely on easily accessible cues," Hairston said.

Researchers point to practical implications for the overtired Overall, the study underlined that learning depends upon two things: exposure to novel material and getting a good night's sleep, Hairston said.

Learning new things, at least in the case of spatial memory, quite literally keeps your brain young by ensuring a better survival rate for new brain cells in the hippocampus. However, not getting enough sleep eliminates the potential benefit of new learning on the hippocampus by suppressing neurogenesis. "Mild, chronic sleep restriction may have long-term deleterious effects on neural functioning," according to the paper.

On the other hand, that sleep-deprived rats did better on a task requiring use of visual and odor cues compared to their better rested counterparts "implies that some kinds of cognitive function are resistant to sleep loss," Hairston said. "This may be significant in human learning as well, and implies that it may be possible to optimize the way information is presented to rested versus fatigued individuals to take advantage of the specific neural substrates that are unaffected by sleep loss," the researchers concluded.

"This finding could be used to design training regimens for chronically sleep-deprived people, including members of the military and medical students," Hairston said. "That said, while the cognitive impairment may be overcome, our findings indicate that mild, chronic sleep restriction may have long-term deleterious effects on neural function," according to the paper.

Further studies could clarify learning strategies the brain employs

One implication of these findings is that sleep restriction disrupts the hierarchy of cognitive processes. That is, spatial learning seemed to be the primary cognitive strategy, and only when it was disrupted by lack of sleep, did a secondary strategy emerge. "It would be interesting to expand our findings to see if other competing processes are similarly affected by sleep restriction," Hairston said.

For example, scientists know that people who have suffered certain types of brain lesions may be unable to screen out irrelevant stimuli such as random noises in a room, something healthy individuals do easily. A flip side is that people with these lesions tend to associate familiar stimuli with new information more rapidly than healthy counterparts, a phenomenon called attention switching.

This suggests that learning to ignore stimuli and rapid attention switching are competing processes, with healthy individuals ignoring familiar stimuli as their primary strategy. It would be interesting to assess whether sleep restriction causes people to lose the ability to screen out extraneous stimuli and preferentially apply attention switching, she said.

American Physiological Society


Related Sleep Current Events and Sleep News Articles


WSU 'deadly force' lab finds racial disparities in shootings
Participants in an innovative Washington State University study of deadly force were more likely to feel threatened in scenarios involving black people.

Researchers obtain key insights into how the internal body clock is tuned
Researchers at UT Southwestern Medical Center have found a new way that internal body clocks are regulated by a type of molecule known as long non-coding RNA.

Study Reveals Immune System is Dazed and Confused During Spaceflight
There is nothing like a head cold to make us feel a little dazed. We get things like colds and the flu because of changes in our immune system.

Scientists use lasers to control mouse brain switchboard
Ever wonder why it's hard to focus after a bad night's sleep? Using mice and flashes of light, scientists show that just a few nerve cells in the brain may control the switch between internal thoughts and external distractions.

Severity of sleep apnea impacts risk of resistant high blood pressure
A new study shows a strong association between severe, untreated obstructive sleep apnea and the risk of elevated blood pressure despite the use of high blood pressure medications.

Poor sleep quality increases suicide risk for older adults, Stanford researcher finds
Older adults suffering from sleep disturbances are more likely to die by suicide than well-rested adults, according to a study led by a researcher at the Stanford University School of Medicine.

Poor sleep quality associated with increased suicide risk in older adults
Reported poor sleep quality, independent of a depressed mood, appears to be associated with an increased risk for suicide in older adults.

Single gene controls jet lag
Scientists at the Salk Institute for Biological Studies have identified a gene that regulates sleep and wake rhythms.

Rooting out skin creams that contain toxic mercury
As countries try to rid themselves of toxic mercury pollution, some people are slathering and even injecting creams containing the metal onto or under their skin to lighten it, putting themselves and others at risk for serious health problems.

Natural light in office boosts health
Office workers with more light exposure at the office had longer sleep duration, better sleep quality, more physical activity and better quality of life compared to office workers with less light exposure in the workplace, reports a new study from Northwestern Medicine and the University of Illinois at Urbana-Champaign.
More Sleep Current Events and Sleep News Articles

Sleep Smarter: 21 Proven Tips to Sleep Your Way To a Better Body, Better Health and Bigger Success

Sleep Smarter: 21 Proven Tips to Sleep Your Way To a Better Body, Better Health and Bigger Success
by Shawn Stevenson (Author)


Sleep Smarter is a fun and entertaining look at how sleep impacts your mind, body, and performance, without skimping on the "how to's" to get the sleep you really deserve. Whether you've struggled with sleep problems, or you're simply interested in living a longer, healthier life, you're going to be blown away with what you learn. Here's just a sampling of what you're going to discover: Why you need to sleep more and exercise less to get the best fitness results.How to feel more energized and refreshed on less hours of sleep.Why poor sleep quality depresses brain function and leads to poor performance.What supplements are safe and helpful, and which ones to avoid (this will shock you!)What exercises you can do to instantly improve your sleep quality.How the clothes you wear to bed can...

Sleep Soundly Every Night, Feel Fantastic Every Day: A Doctor's Guide to Solving Your Sleep Problems

Sleep Soundly Every Night, Feel Fantastic Every Day: A Doctor's Guide to Solving Your Sleep Problems
by Robert Rosenberg DO FCCP (Author)


If you have insomnia, always feel tired, or can't sleep because of a restless or snoring partner, help is here. Do you have trouble getting to sleep? Do you take a long time to get up and get going in the morning? Do you wake up feeling like you barely slept at all? If you or someone you love has problems sleeping, Dr. Robert S. Rosenberg will help you identify the issue and provide targeted solutions so you can start awakening refreshed and renewed immediately. Based on the most recent research and including real patient stories from his practice, Dr. Rosenberg will help you: Prevent and manage sleep disorders, including insomnia, sleep apnea, restless legs syndrome, snoring, sleepwalking, and sleep eating Find relief from your symptoms with clinically tested options Benefit from new...

Sleep

Sleep
by Charles Anthony Silvestri (Author), Anne Horjus (Illustrator)


(Book). This beautifully illustrated children's book is the latest result of a collaboration between poet Charles Anthony Silvestri and composer Eric Whitacre. The text was originally written to accompany Whitacre's enormously popular choral work "Sleep." This hardcover book is a new way to enjoy and share the poem, with lavish illustrations by Anne Horjus. Enjoy the book, explore the music which inspired it, and see the connections between words and art and music which are everywhere.

The Effortless Sleep Method:  The Incredible New Cure for Insomnia and Chronic Sleep Problems

The Effortless Sleep Method: The Incredible New Cure for Insomnia and Chronic Sleep Problems
by Sasha Stephens (Author)


The Effortless Sleep Method is the approach insomniacs all over the world have been waiting for. This hugely effective method offers a simple and permanent solution for long-term and new insomniacs alike.

The Effortless Sleep Method gives you something no other insomnia book can; an entirely different way of looking at insomnia. The step-by-step insomnia recovery sleep program contained in this book, doesn't just treat insomnia, it totally undermines it. This is not another dry as dust reference book written by a doctor, but a lively, empowering book which connects the sufferer intimately to one who has gone through the same pain.

Sasha Stephens suffered a full fifteen years with crippling, terrifying insomnia before a chance event enabled her to see the problem from an...

Dreamland: Adventures in the Strange Science of Sleep

Dreamland: Adventures in the Strange Science of Sleep
by David K. Randall (Author)


An engrossing examination of the science behind the little-known world of sleep. Like many of us, journalist David K. Randall never gave sleep much thought. That is, until he began sleepwalking. One midnight crash into a hallway wall sent him on an investigation into the strange science of sleep.

In Dreamland, Randall explores the research that is investigating those dark hours that make up nearly a third of our lives. Taking readers from military battlefields to children’s bedrooms, Dreamland shows that sleep isn't as simple as it seems. Why did the results of one sleep study change the bookmakers’ odds for certain Monday Night Football games? Do women sleep differently than men? And if you happen to kill someone while you are sleepwalking, does that count as murder?
The Secret Life of Sleep

The Secret Life of Sleep
by Kat Duff (Author)


It has become increasingly clear that our sleep shapes who we are as much as, if not more than, we shape it.

While most sleep research hasn’t ven­tured far beyond research labs and treatment clinics, The Secret Life of Sleep taps into the enormous reservoir of human experiences to illuminate the complexities of a world where sleep has become a dwindling resource.

With a sense of infectious curiosity, award winning author Kat Duff mixes cutting-edge research with insightful narratives, surpris­ing insights, and timely questions to help us better understand what we’re losing before it’s too late.

The Secret Life of Sleep tackles the full breadth of what sleep means to people the world over. Embark on an exploration of what lies behind and beyond our eyelids...

The Harvard Medical School Guide to a Good Night's Sleep (Harvard Medical School Guides)

The Harvard Medical School Guide to a Good Night's Sleep (Harvard Medical School Guides)
by Lawrence Epstein (Author), Steven Mardon (Author)


Put your sleep problems to rest with this proven six-step plan How many times have you heard it's important to get a good night's sleep? It sounds simple, but it isn't always easy. Now one of the nation's leading sleep experts gives you a step-by-step program for overcoming sleep problems from insomnia and snoring to restless legs syndrome and sleep apnea. Dr. Lawrence Epstein of Harvard Medical School reveals his proven six-step plan to maximize your nights and energize your days. He explains the health benefits of sleep and identifies signs of sleep problems as he gives in-depth advice on how to: Turn your bedroom into the optimal sleep environment Finally overcome insomnia Silence buzz-saw snoring Relax restless legs Deal with daytime exhaustion Determine if sleep medication is...

Sleep, Interrupted: A physician reveals the #1 reason why so many of us are sick and tired

Sleep, Interrupted: A physician reveals the #1 reason why so many of us are sick and tired
by Steven Y. Park MD (Author)


Maybe you're stressed out and tired, and have put on a little weight. Or you have persistent pain you and your doctor can't explain. Man or woman, you may be fighting fluctuating hormone levels. Or maybe you snore like a freight train. Anything that narrows the throat and interrupts sleep, particularly breathing problems brought on by sleep position, illness, life changes, or your anatomy, may be key to understanding a host of common health issues. In this groundbreaking book, Dr. Steven Park outlines a simple, rational explanation for what s making you sick, and provides guidance for treatment options that address specific health problems.

Sleep: A Groundbreaking Guide to the Mysteries, the Problems, and the Solutions

Sleep: A Groundbreaking Guide to the Mysteries, the Problems, and the Solutions
by Carlos H. Schenck (Author)


We spend more than 200,000 hours sleeping in a lifetime, the equivalent of more than 8,000 days. Yet research has only just begun to decode the mysteries behind what can go wrong. Here, Dr. Carlos H. Schenck, one of the most prominent sleep doctors and researchers in the country, takes us on an incredible journey into the mechanisms of sleep, and the spectrum of disorders that can occur when these mechanisms go bizarrely awry.

Dr. Schenck discusses the causes and treatments for common problems-insomnia, restless legs syndrome, sleep apnea, and more. But what sets this book apart is the rare glimpse it offers into the cutting-edge science that he and others have pioneered in identifying, understanding, and explaining the realm of "parasomnias"-the mysterious, more extreme sleep...

Ultimate Sleep: Five Easy Steps to Help You Fall Asleep Quickly, Rest Peacefully and Wake Up Refreshed

Ultimate Sleep: Five Easy Steps to Help You Fall Asleep Quickly, Rest Peacefully and Wake Up Refreshed


Ultimate Sleep - The easy 5 step method to improving your sleep tonight!

$6.99 Now $2.99 for a limited time only!

In today's society it is becoming increasing difficult to get the amount and quality of sleep that our body and mind requires. Ultimate Sleep is a 5 step guide to changing that; helping you to feel more relaxed in an evening, and more refreshed in a morning. After learning more about what sleep actually is and how it affects our body, you'll then get access to the 5 steps to sleep success;

1) Diet and Exercise - a definitive look at what foods impair sleep, what foods are conducive to sleep, how to plan your meals for optimal rest, and ensure you are taking in the necessary vitamins and minerals for proper sleep. Also, how exercise may...

© 2014 BrightSurf.com