Are learning and unlearning bedfellows?
The researchers chose this kind of passive auditory stimulation -- particularly well suited for subjects who are asleep -- to explore the connection between learning and sleep. They exposed sleeping volunteers to noise that incorporated repeated sounds and then tracked their brain activity using electroencephalography. Since the brain reacts differently to new, unfamiliar sounds as opposed to learned sounds, electroencephalographic analysis can show researchers whether a sound heard has been memorized, even when the subject is not awake. Analysis of brain activity in subjects while asleep, and of their behavioral responses after waking, demonstrated they recognized the noises heard during both REM sleep and stage N2 sleep. These findings reveal that our brains are able to learn while in these two sleep phases. And indeed, during both phases -- even though they are very different in terms of brain activity -- it has been shown that the brain can process complex information, whether ...