While recently going through some of my seemingly endless stacks of papers, I came across an article I clipped out of Newsweek about a year ago. The subject is sleep and memory and it had some interesting information about how sleep affects our ability to remember things. Since the dominant theme of my posts for the past 6 weeks has been about sleep related issues it seemed like a good idea to share the highlights of this article with you as well.
According to this article, when you are asleep (the time your body is supposed to be resting and recovering), your brain (the organ that directs you to sleep in the first place) is extraordinarily active. And much of that activity helps the brain to learn, remember and forge new connections to enforce that learning and the formation of memory.
Apparently we all have several different types of memory –including declarative (retrievable, fact-based information), episodic (events from your life), and procedural (how to do something)– and researchers have designed ways to test each one of them. Experiences we have that become memories are laid down first in the hippocampus, obliterating whatever is underneath. If a memory is to be retained, it must be shipped from the hippocampus to a place where it will endure –the neocortex, the wrinkled outer layer of the brain where higher thinking takes place. Unlike the hippocampus, the neocortex is a master at weaving the old with the new. And partly because it keeps incoming information at bay, sleep is the best time for the “undistracted” hippocampus to shuttle memories to the neo cortex, and for the neocortex to link them to related memories.
You can think of it as your brain trying to squeeze in some extra practice time while you’re asleep –bringing some truth to the old adage “sleep on it.” It’s not just memory that’s improved by sleep. Recent studies indicate that sleep not only helps store facts, it also helps make connections between them. Some sleep researchers believe that for every 2 hours we’re awake, the brain needs an hour of sleep to figure out what all these experiences mean, and that sleep pays a crucial role in constructing the meaning our lives come to hold as a result.
Sleep deprivation experiments have shown that a tired brain has a difficult time capturing memories of all sorts. But the most interesting finding revealed in this article is that sleep deprivation is more likely to cause us to forget information associated with positive emotion than information linked to negative emotion! This could explain, at least in part, why sleep deprivation can trigger depression in some people: memories tainted with negative emotions are more likely than positive ones to “stick” in the sleep-deprived brain. All the more reason to get a good night’s rest!
