Why Sleep? Snoozing May Be Strategy To Increase Efficiency, Minimize Risk

New research concludes that sleep's primary function is to increase animals' efficiency and minimize their risk by regulating the duration and timing of their behavior. (Credit: iStockphoto/Justin Horrocks)

From Science Daily:

ScienceDaily (Aug. 23, 2009) — Bats, birds, box turtles, humans and many other animals share at least one thing in common: They sleep. Humans, in fact, spend roughly one-third of their lives asleep, but sleep researchers still don't know why.

According to the journal Science, the function of sleep is one of the 125 greatest unsolved mysteries in science. Theories range from brain "maintenance" — including memory consolidation and pruning — to reversing damage from oxidative stress suffered while awake, to promoting longevity. None of these theories are well established, and many are mutually exclusive.

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Terrifying 'Sleep Paralysis' Needs More Attention

From Live Science:

Sleep paralysis can be a terrifying experience for the near 50 percent of people who have had an episode. It's the middle of the night, your eyes are open, dark shapes are gathering around you, something has grabbed your feet, and you can't move. You can't even scream.

A new article by British researchers calls for more attention to be paid in the medical community to sleep paralysis, also known as "night terrors."

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First Human Gene Implicated In Regulating Length Of Human Sleep

The discovery of the first gene involved in regulating the optimal length of human sleep offers a window into a key aspect of slumber. (Credit: iStockphoto/Diane Diederich)

From Science Daily:

ScienceDaily (Aug. 14, 2009) — Scientists have discovered the first gene involved in regulating the optimal length of human sleep, offering a window into a key aspect of slumber, an enigmatic phenomenon that is critical to human physical and mental health.

The team, reporting in the Aug. 14, 2009 issue of Science, identified a mutated gene that allows two members of an extended family to thrive on six hours of sleep a day rather than the eight to eight-and-a-half hours that studies have shown humans need over time to maintain optimal health. Working from this discovery, the scientists genetically engineered mice and fruit flies to express the mutated gene and study its impact.

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Brains Replay Memories While We Sleep And Store The Highlights, Claim Scientists

From The Telegraph:

We may think we are asleep - but deep in the recesses of our mind a "memory editor" is working overtime, replaying the experiences of the day and storing the highlights on our brain's version of a video recorder, claim scientists.

Researchers have discovered that the mind keeps most memories for just a day but then at night acts like a film editor sifting through the "video clips" before transferring the best bits to long term storage in our own movie archive.

The research has "profound implications" for the importance of sleep and its link with long term memory, they said.

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Larks and Owls: How Sleep Habits Affect Grades

Image Source / Corbis

From Time:

There are at least a few in every college dorm: students who seem to exist in their own time zone, in bed hours before everyone else and awake again at daybreak, rested and prepared for the morning's first lecture.

Sleep researchers refer to these early risers as larks (midnight-oil-burners are known as owls), and new data presented this week at the annual Associated Professional Sleep Societies suggest that a student's preferred sleeping schedule has a lot to do with his or her grade-point average in school. In one study, psychologists at Hendrix College in Arkansas found that college freshmen who kept night-owl hours had lower GPAs than early birds. Another group at the University of Pittsburgh revealed that poor sleep habits among high-schoolers led to lower grades, particularly in math.

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Let Me Sleep On It: Creative Problem Solving Enhanced By REM Sleep

From Science Daily:

ScienceDaily (June 9, 2009) — Research led by a leading expert on the positive benefits of napping at the University of California, San Diego School of Medicine suggests that Rapid Eye Movement (REM) sleep enhances creative problem-solving. The findings may have important implications for how sleep, specifically REM sleep, fosters the formation of associative networks in the brain.

The study by Sara Mednick, PhD, assistant professor of psychiatry at UC San Diego and the VA San Diego Healthcare System, and first author Denise Cai, graduate student in the UC San Diego Department of Psychology, shows that REM directly enhances creative processing more than any other sleep or wake state. Their findings will be published in the June 8th online edition of the Proceedings of the National Academy of Sciences (PNAS).

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Neurons Take A Break During Slow-Wave Sleep

From Science News:

The time off prevents interruptions that could wake a person up.

Even neurons need quiet time. A new study shows the brain cells take time out while you sleep, preventing you from waking up at the drop of a hat or other nonthreatening object.

For decades, scientists have been measuring electrical activity in the brain during sleep with electroencephalograms, or EEGs. Researchers easily recognize the hallmark dips and blips of each stage of sleep, but what brain cells are doing to produce the signals hasn’t been apparent.

Now, a new study in the May 22 Science shows that a prominent electrical signal of slow-wave sleep, called the K-complex, indicates downtime for neurons. The quiet periods could help people ignore distractions, such as sounds and touches, and stay asleep, the researchers report.

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Molecular Link Between Sleep And Weight Gain

From Science Daily:

ScienceDaily (May 23, 2009) — There appears to be a link between sleep and weight control, with some studies indicating that sleep disruption can increase weight gain and others that diet affects sleep. Victor Uebele and colleagues, at Merck Research Laboratories, West Point, have now provided further evidence to support this association by showing that T-type calcium channels regulate body weight maintenance and sleep in mice.

These data suggest that sleep and circadian treatment approaches may be of benefit in the fight against obesity.

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Sleep Can Improve Your Word Power

From The Telegraph:

Reading bedtime stories to children could help to improve their vocabulary, new research suggests.

Psychologists have discovered that a good night's sleep plays a crucial role in allowing the brain to store and remember new words learned during the day.

People who were asked to learn a set of fictitious words were better at remembering them after they had spent time asleep than if they were asked to recall the words just a few hours after being taught them.

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Sleep: Spring Cleaning For The Brain?

On the left, the brain of the well-rested blue fly has low levels of a synaptic protein called BRP in this 3D view from a confocal mircoscope. On the right, the brain of the sleep-deprived fly glows orange in areas of BRP concentration. (Bruchpilot or BRP is a protein involved in communication between neurons.)In the tired fly, the protein is present at high concentartions in three major areas of the fly's brain that are associated with learning. Sleep reduces the levels of this protein, an indication that synapses get smaller and/or weaker. This process of "downscaling" may be important so the brain is reset to normal levels of synaptic activity and can begin learning again the next day. (Credit: Courtesy of UW Health Public Affairs)

From Science Daily:

ScienceDaily (Apr. 11, 2009) — If you've ever been sleep-deprived, you know the feeling that your brain is full of wool.

Now, a study published in the April 3 edition of the journal Science has molecular and structural evidence of that woolly feeling — proteins that build up in the brains of sleep-deprived fruit flies and drop to lower levels in the brains of the well-rested. The proteins are located in the synapses, those specialized parts of neurons that allow brain cells to communicate with other neurons.

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Why Dreams Are So Difficult To Remember: Precise Communication Discovered Across Brain Areas During Sleep

New research points to how memories are formed, transferred, and ultimately stored in the brain--and how that process varies throughout the various stages of sleep. (Credit: iStockphoto/Diane Diederich)

From Science Daily:

ScienceDaily (Mar. 9, 2009) — By listening in on the chatter between neurons in various parts of the brain, researchers from the California Institute of Technology (Caltech) have taken steps toward fully understanding just how memories are formed, transferred, and ultimately stored in the brain--and how that process varies throughout the various stages of sleep.

Their findings may someday even help scientists understand why dreams are so difficult to remember.

Scientists have long known that memories are formed in the brain's hippocampus, but are stored elsewhere--most likely in the neocortex, the outer layer of the brain. Transferring memories from one part of the brain to the other requires changing the strength of the connections between neurons and is thought to depend on the precise timing of the firing of brain cells.

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Why Sleep Is Needed To Form Memories

The world as the brain sees it. Optical 'polar' maps of the visual cortex are generated by measuring micro-changes in blood oxygenation as the left eye (left panel) or right eye is stimulated by bars of light of different orientations (0-180 degrees). The cortical response to each stimulus is pseudo-colored to represent the orientation that best activates visual cortical neurons. If vision is blocked in an eye (the right eye in this example) during a critical period of development, neurons no longer respond to input from the deprived eye pathway (indicated by a loss of color in the right panel) and begin to respond preferentially to the non-deprived eye pathway. These changes are accompanied by alterations in synaptic connections in single neurons. This process, known as ocular dominance plasticity, is enhanced by sleep via activation of NMDA receptors and intracellular kinase activity. Through these mechanisms, sleep strengthens synaptic connections in the non-deprived eye pathway. (Credit: Marcos Frank, PhD University of Pennsylvania)

From Science Daily:

ScienceDaily (Feb. 12, 2009) — If you ever argued with your mother when she told you to get some sleep after studying for an exam instead of pulling an all-nighter, you owe her an apology, because it turns out she's right. And now, scientists are beginning to understand why.

In research published recently in Neuron, Marcos Frank, PhD, Assistant Professor of Neuroscience, at the University of Pennsylvania School of Medicine, postdoctoral researcher Sara Aton, PhD, and colleagues describe for the first time how cellular changes in the sleeping brain promote the formation of memories.

"This is the first real direct insight into how the brain, on a cellular level, changes the strength of its connections during sleep," Frank says.

The findings, says Frank, reveal that the brain during sleep is fundamentally different from the brain during wakefulness.

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Catching Up On Sleep

Can You Catch Up On Lost Sleep? -- Scientific American

Let's do some sleep math. You lost two hours of sleep every night last week because of a big project due on Friday. On Saturday and Sunday, you slept in, getting four extra hours. Come Monday morning, you were feeling so bright-eyed, you only had one cup of coffee, instead of your usual two. But don't be duped by your apparent vim and vigor: You're still carrying around a heavy load of sleepiness, or what experts call "sleep debt"—in this case something like six hours, almost a full nights' sleep.

Sleep debt is the difference between the amount of sleep you should be getting and the amount you actually get. It's a deficit that grows every time we skim some extra minutes off our nightly slumber. "People accumulate sleep debt surreptitiously," says psychiatrist William C. Dement, founder of the Stanford University Sleep Clinic. Studies show that such short-term sleep deprivation leads to a foggy brain, worsened vision, impaired driving, and trouble remembering. Long-term effects include obesity, insulin resistance, and heart disease. And most Americans suffer from chronic deprivation.

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The Snore Wars

From Time Magazine:

I have always been happy that I'm not a snorer — or at least I was until recently, when my wife told me otherwise. After a few days of adamant denials, I decided to place a tape recorder on the bedside table. When I hit play the next morning, I was surprised to hear a rhythmic, rumbling noise that was enough to disturb my wife's sleep. In my case, the problem was transient, caused by a recent bout of allergies and sinus trouble. When my breathing cleared up, so did the snoring. Yet for millions of other couples out there, snoring is a cause not just of health worries but also of marital woes.

According to a recent study, nearly 1 out of 4 people married to a snorer will eventually be driven out of the bedroom rather than spend another night battling for sleep. Sometimes even that's not enough. "I see a lot of patients whose spouses can't just go to another room. They have to escape to a whole other area of the house," says Dr. Marc Kayem, medical director of the Snoring and Apnea Center of California, in Los Angeles.

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