Lunes 24 de Noviembre de 2008

Napping boosts "sophisticated" memory
Por Lauran Neergaard

Just in time for the holidays, some medical advice most people will like: Take a nap. Interrupting sleep seriously disrupts memory-making, compelling new research suggests. But on the flip side, taking a nap may boost a sophisticated kind of memory that helps us see the big picture and get creative.

"Not only do we need to remember to sleep, but most certainly we sleep to remember," is how Dr. William Fishbein, a cognitive neuroscientist at the City University of New York, put it at a meeting of the Society for Neuroscience last week.

Good sleep is a casualty of our 24/7 world. Surveys suggest few adults attain the recommended seven to eight hours a night.

Way too little clearly is dangerous: Sleep deprivation causes not just car crashes but all sorts of other accidents. Over time, a chronic lack of sleep can erode the body in ways that leave us more vulnerable to heart disease, diabetes and other illnesses.

But perhaps more common than insomnia is fragmented sleep _ the easy awakening that comes with aging, or, worse, the sleep apnea that afflicts millions, who quit breathing for 30 seconds or so over and over throughout the night.

Indeed, scientists increasingly are focusing less on sleep duration and more on the quality of sleep, what's called sleep intensity, in studying how sleep helps the brain process memories so they stick. Particularly important is "slow-wave sleep," a period of very deep sleep that comes earlier than better-known REM sleep, or dreaming time.

Fishbein suspected a more active role for the slow-wave sleep that can emerge even in a power nap. Maybe our brains keep working during that time to solve problems and come up with new ideas. So he and graduate student Hiuyan Lau devised a simple test: documenting relational memory, where the brain puts together separately learned facts in new ways.

First, they taught 20 English-speaking college students lists of Chinese words spelled with two characters _ such as sister, mother, maid. Then half the students took a nap, being monitored to be sure they didn't move from slow-wave sleep into the REM stage.


  24/11/2008. The Huffington Post.