The Connection Between Sleep And Memory

When you're studying for an exam, is there something you can do to retain the information better while you sleep? ""The question is, what determines which information is going to be kept and which information is lost,"" says neuroscientist Ken Paller. With support from the National Science Foundation (NSF), Paller and his team at Northwestern University are studying the connection between memory and sleep, and the possibilities of boosting memory storage while you snooze. ""We think many stages of sleep are important for memory. However, a lot of the evidence has shown that slow-wave sleep is particularly important for some types of memory,"" explains Paller. Slow-wave sleep is often referred to as ""deep sleep,"" and consists of stages 3 and 4 of non-rapid-eye-movement sleep. Researchers recorded electrical activity generated in the brain using EEG electrodes attached to the scalp. They thus determined whether the subjects entered ""deep sleep"" and only those who did participated in the reinforcement experiments. In both experiments, participants did a better job remembering what was reinforced while they slept, compared to what was not reinforced. ""We think that memory processing happens during sleep every night,"" says Paller. ""We're at the beginning of finding out what types of memory can be reinforced, how large reinforcement effects can be, and what sorts of stimuli can be used to reactivate memories so that they can be better consolidated."" Paller's goal is to better understand the fundamental brain mechanisms responsible for memory. And that, in turn, may help people with memory problems, including those who find themselves more forgetful as they age.