Science Current Events | Science News |

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

Want to remember new names? Sleep on it
A new study by investigators at Brigham and Women's Hospital (BWH) offers an additional reason to get a good night's sleep.

Children who take ADHD medicines have trouble sleeping, new study shows
Stimulant medications for attention-deficit/hyperactivity disorder (ADHD) cause sleep problems among the children who take them, a new study from the University of Nebraska-Lincoln concludes.

Vitamin D does not reduce colds in asthma patients
Vitamin D supplements do not reduce the number or severity of colds in asthma patients, according to a new study published online ahead of print publication in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

Parents' top fears about teen cellphone use
Parents' fears about their teenagers' heavy use of cell phones and social media may be exaggerated, according to a new report from Duke University researchers. However, there are important exceptions in the areas of cyberbullying and sleep disruption.

Gravity, who needs it?
What happens to your body in space? NASA's Human Research Program has been unfolding answers for over a decade.

New drowsy driving position statement calls for greater public awareness, education
A new position statement from the American Academy of Sleep Medicine warns that drowsy driving is a serious public health concern requiring greater public awareness and increased efforts to improve preventive education.

Treating epilepsy and brain traumas by neurotransmitters
Roustem Khazipov, Head of the group of researchers from Kazan Federal University and Aix-Marseille University, "Brain activity is based on both excitatory and inhibitory actions regulated by neurotransmitters.

Yoga may lessen side effects in men undergoing prostate cancer treatment
Men with prostate cancer who are undergoing radiation therapy can benefit from yoga, researchers at the Perelman School of Medicine at the University of Pennsylvania reported at the Society of Integrative Oncology's 12th International Conference.

Lead exposure impacts children's sleep
A new research study from the University of Pennsylvania School of Nursing (Penn Nursing) shows that lead exposure in early childhood are associated with increased risk for sleep problems and excessive daytime sleepiness in later childhood.

A mouse model offers new insights into a rare lung disease
New research from an investigative team at the University of Cincinnati (UC) has identified biomarkers and potential therapeutic approaches that may hold the key to treating pulmonary alveolar microlithiasis (PAM), a rare lung disease.
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...

Go the F**k to Sleep

Go the F**k to Sleep
by Adam Mansbach (Author), Ricardo Cortés (Illustrator)

"Nothing has driven home a certain truth about my generation, which is approaching the apex of its childbearing years, quite like this."
--The New Yorker

"A parenting zeitgeist"
--Washington Post

"A hilarious take on that age-old problem: getting the beloved child to go to sleep."
--National Public Radio

"A new Bible for weary parents"
--New York Times

"Resonates powerfully with almost everyone"
--Boston Globe

"Go the F*** to Sleep challenges stereotypes, opens up prototypes, and acknowledges that shared sense of failure that comes to all parents who weary of ever getting their darling(s) to sleep and briefly resuming the illusion of a life of their own."
--Midwest Book Review

Go the F*** to Sleep is a bedtime book for parents...

The 8-Hour Sleep Paradox: How We Are Sleeping Our Way to Fatigue, Disease and Unhappiness

The 8-Hour Sleep Paradox: How We Are Sleeping Our Way to Fatigue, Disease and Unhappiness

#1 Amazon Best Seller
As rates of disease, fatigue and unhappiness skyrocket, teams of scientists are scrambling to find cures. But the cure we need is an old one: sleep. Getting the proverbial eight hours each night isn't enough anymore thanks to our modern lifestyle and diet. Sleep medicine dentist Dr. Mark Burhenne discusses how modern sleep is destroying our health and what we can do about it to heal and be our best, brightest, most capable selves.

"I can’t stress enough how important this book is for people to read as it will help you better understand why you need quality sleep, what the pitfalls or correctable problems may be that are preventing you from getting it, and what you can do about it. I highly recommend you read the 8-Hour Sleep Paradox and get...

Sleep Secrets: How to Fall Asleep Fast, Beat Fatigue and Insomnia and Get A Great Night's Sleep

Sleep Secrets: How to Fall Asleep Fast, Beat Fatigue and Insomnia and Get A Great Night's Sleep
by Ronald M. Bazar

Sleep Secrets is the book you should read for good, practical information on how to get a good night’s sleep. Insomnia, sleep deprivation, snoring and sleep apnea — this comprehensive resource has it all. … Dr. Andrew Weil

Andrew Thomas Weil is an American medical doctor, teacher, and best-selling author on holistic health. He is founder, professor, and director of the Arizona Center for Integrative Medicine at the University of Arizona.

* * * * * * * *

After decades of research, author, Ronald M. Bazar, presents Sleep Secrets, an all-inclusive guide to discovering the underlying causes of your insomnia and how to cure it.

From ancient time-proven sleep wisdom to cutting-edge products, from expert sleep-doctor advice to...

Say Good Night to Insomnia: The Six-Week, Drug-Free Program Developed At Harvard Medical School

Say Good Night to Insomnia: The Six-Week, Drug-Free Program Developed At Harvard Medical School
by Gregg D. Jacobs (Author), Herbert Benson (Introduction)

The bestselling guide to curing insomnia without drugs by "a pioneer" of the field, now updated with the latest research (The Wall Street Journal)For the past ten years, sleep-deprived Americans have found natural, drug-free relief from insomnia with the help of Dr. Gregg D. Jacobs's Say Good Night to Insomnia. Jacobs's program, developed and tested at Harvard Medical School and based on cognitive behavioral therapy, has been shown to improve sleep long-term in 80 percent of patients, making it the gold standard for treatment. He provides techniques for eliminating sleeping pills; establishing sleep-promoting behaviors and lifestyle practices; and improving relaxation, reducing stress, and changing negative thoughts about sleep.In this updated edition, Jacobs surveys the limitations and...

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...

A Book of Sleep

A Book of Sleep
by Il Sung Na (Author)

When the sky grows dark
and the moon glows bright,
everyone goes to sleep . . .
except for the watchful owl!

With a spare, soothing text and beautifully rich and textured illustrations of a starry night, this is the perfect “book of sleep.” Join the owl on his moonlit journey as he watches all the other animals settle in for the night: some sleep standing up, while some sleep on the move! Some sleep peacefully alone, while others sleep all together, huddled close.

Il Sung Na makes his American debut with this gorgeous bedtime offering. While each animal rests in its own special way, little ones will also drift off to a cozy sleep.

The Rabbit Who Wants to Fall Asleep: A New Way of Getting Children to Sleep

The Rabbit Who Wants to Fall Asleep: A New Way of Getting Children to Sleep
by Carl-Johan Forssén Ehrlin (Author), Irina Maununen (Illustrator)

The groundbreaking #1 bestseller is sure to turn nightly bedtime battles into a loving and special end-of-day ritual. This child-tested, parent-approved story uses an innovative technique that brings a calm end to any child’s day.
Do you struggle with getting your child to fall asleep?
Join parents all over the world who have embraced The Rabbit Who Wants to Fall Asleep as their new nightly routine.
When Roger can’t fall asleep, Mommy Rabbit takes him to see Uncle Yawn, who knows just what to do. Children will join Roger on his journey and be lulled to sleep alongside their new friend.
Carl-Johan Forssén Ehrlin’s simple story uses a unique and distinct language pattern that will help your child relax and fall asleep—at bedtime or...

Where Do Diggers Sleep at Night?

Where Do Diggers Sleep at Night?
by Brianna Caplan Sayres (Author), Christian Slade (Illustrator)

The bedtime rituals of little diggers and dump trucks at a construction site should be quite familar to kids saying goodnight. Young readers will identify with fire engines, tractors and monster trucks as the vehicles ask for one more story while their mommy trucks tuck them in, and their daddy trucks sing a goodnight song. Children who can't get enough of trucks will love Brianna Caplan Sayres things-that-go bedtime story.

From the Hardcover edition.

© 2015