The Amazing Link Between Sleep and Memory

Napping is a guilty pleasure... one all of us, if we’re lucky, engage in at one time or another, especially during the cold, dark months of winter.

And it seems interestingly that new research has found the link between sleep and memory and that short naps help actually improve to our creativity and our ability to see the big picture.

Too many of us, in our got-to-be-everywhere, 24/7 world, try to act like sleep is something we can do without. But we can’t.

Enter the power nap... a short 15 to 20 minute rest period outside our normal nightly routine, just enough to get us through.

Sleep depravation is a major problem that’s a factor behind many types of accidents, not the least of which happen when driving.

Surveys show that most adults don’t get the seven to eight hours recommended each night to recharge, rebuild and remember.

Over time, lack of sleep can seriously impact the body, leaving you open to diabetes, heart disease and other dangerous conditions.

You only have to think about when you have been ill, and restorative nature of sleep, and how you wake feeling better.

In fact, sleep is as important as a healthy, balanced diet and regular exercise keeping the body strong and healthy.

“Not only do we need to remember to sleep, but most certainly we sleep to remember,” says Dr. William Fishbein, a cognitive neuroscientist at the City University of New York, one of our nation’s leading urban public universities. Dr. Fishbein presented the sleep and memory research last week In Washington D.C. at the annual meeting of the Society for Neuroscience.

As a natural part of aging our sleep becomes more fragmented, we wake more often during the night. Serious conditions like sleep apnea, where breathing stops for short periods so that you are jolted wake, make getting a good night’s sleep impossible.

But fragmented sleep impacts us effects us for days as well. Research on both animals and human subjects shows that we continue to struggle for weeks, even after our sleeping patterns return to normal.

The most recent research on sleep has focused less on the duration of your sleeping period and more on the quality of the sleep, termed sleep intensity.

This period of very deep sleep, known as slow wave sleep (not as well known as dreaming REM sleep) comes first, helping the brain process memories so they stay put. Dr. Fishbein had suspected a bigger role for slow wave sleep periods... perhaps the reason power naps leave us so refreshed.

In the research, 20 English-speaking college students were shown lists of Chinese words of two characters - mother, sister, maid. Then half the students took a nap, and were closely monitored to be sure they didn’t go from slow wave sleep to the REM (dreaming) stage.

When they woke, they took a multiple-choice test of Chinese words they’d never seen. Subjects who napped (an unheard of 90 minute nap) did much better at automatically learning that the first of the two-pair characters in the words they’d memorized earlier always meant the same thing - female. This group, more than the non-nappers were more likely to choose a new word with characters that meant “princess” not “ape.”

“The nap group has essentially teased out what’s going on,” Fishbein concludes.

Another study used a different approach to prove the importance of slow wave sleep on memory.

Researchers from the University of Wisconsin interrupted subjects’ slow wave sleep with a beep that was just loud enough to disturb sleep, but not fully rouse the subject.

Upon waking those people who’d been beeped couldn’t remember a task they’d learned the day before as well as subjects whose slow-wave sleep hadn’t been disrupted by the tone.

The “take to bed” message is this.

If you suspect sleep apnea, get yourself treated. Just as you eat well and exercise to keep your body (and mind) healthy, do all you can to foster good sleep habits so your body, mind and memory get the chance to recharge.

Regularly depriving yourself of sleep... and then playing catch up on the weekend is sleep’s version of binge eating - not healthy for the long haul.

As for all you nappers out there... take heart; the sum of all this latest sleep research stands in support of those sleep and memory, and that power naps leave you recharged and ready to go. -Kirsten Whittaker

Sleeping in a dark room may prevent depression

Do you fall asleep while reading, with a lamp still turned on? Doze off with the glow of a television in your bedroom? Perhaps you turn off the lights when you go to bed. But think about it: is your room really totally dark? Maybe there's a light from a clock radio or night light or perhaps street lights peek through the bedroom blinds. This not-completely-dark room might not keep you awake but it could lead to symptoms of depression. That's the conclusion of a new study presented recently in Chicago at the annual meeting of the Society for Neuroscience and slated for publication in the December 28, 2009, issue of the journal Behavioural Brain Research.

The Ohio State University research involved 24 male laboratory mice. Half were housed in light for 16 hours a day and darkness for 8 hours, while the others lived in a lighted area 24 hours a day. Half of each group of lab animals had opaque tubes in their cages where they could escape the light at any time. The other half had tubes that were clear and did not offer any respite from the light.

After three weeks, the researchers used a series of tests to measure depression and anxiety in the rodents (including several tests used by drug companies to test anti-depressive and anti-anxiety drugs on animals before they are tried on people). For example, mice usually like to drink sugar-laced water. But if they have symptoms of depression, they don't drink as much. Researchers assume this is because they don't get the pleasure they would normally get from the sweet water due to depressive symptoms. In all the tests, the mice who had to live and sleep in constant light with no chance of spending time in darkness showed more depressive-like symptoms than the animals with normal light-dark cycles.

"The ability to escape light seemed to quell the depressive effects," Laura Fonken, lead author of the study and a graduate student in psychology at Ohio State University, said in a statement to the media. "But constant light with no chance of escape increased depressive symptoms."

The scientists concluded that the use of artificial light at night may have harmful effects on human health. "This is important for people who work night shifts, and for children and others who watch TV late into the night, disrupting their usual light-dark cycle," Fonken said. -naturalnews