Dreams May Help Us Remember
July 18 -- Getting a good night’s sleep after trying to master a tough newtask might just reinforce what you have learned.
European researchers say dreaming might be the brain’s way ofreplaying experiences and lessons so that they are fixed in thememory for use later on.
The scientists used advanced imaging technology and found thatthe same regions of the brain that are buzzing while we learn a newtask are also active while we dream. This heightened activity wasobserved during the brief but active stage known as rapid-eyemovement, or REM, sleep.
The study was published in the August issue of NatureNeuroscience and was led by Pierre Maquet of the University ofLiege in Belgium.
Animal studies had shown similar results. Rats that ran newroutes through mazes showed increased activity in the same portionsof their brains when they slept afterward. But the human brain ismore complex.
“It is wonderful to see such results demonstrated in humans forthe first time,” said David Silbersweig, co-director of thefunctional neuroimaging research laboratory at the New York-CornellMedical Center.
Why Sleep?Humans spend one-third of their lives asleep, but sleep’spurpose is poorly understood. Among other things, scientistsbelieve dreaming may help sort out emotions, impressions and otherideas.
In the study, 18 volunteers ages 18 to 25 spent several hourslearning how to quickly recognize symbols as they flashed on acomputer screen and press the same symbol on a keyboard.
During the test, the activity in several regions of their brainswas monitored by PET scans, which reveal how the brain isfunctioning by watching its use of glucose and oxygen, the fuels ofbrain cells.
Groups of volunteers were tested in several ways. Those who tookthe computer test for several hours, slept and retook the test whenthey woke up scored the highest, with even faster reaction timesafter they slept.
PET scans showed that during REM sleep their brain activity andblood flow were similar to when they were taking the test.
