Feb 14 2009
Confidence in Sleep
For a number of years now psychologists have known there is a connection between sleep and memory. In one experiment on sleep and learning I can recall, one variable was controlled, sleep, to determine if it caused a change in the other, learning. The researchers had students spend a specific amount of time learning new material. The subjects were then broken into groups that were allowed to sleep for differing durations–from no hours (pulling an “all-nighter”) to a full night’s sleep. The results revealed that duration of sleep strongly influenced how much was remembered. It was hypothesized that when individuals sleep their experiences are converted into long term memory.
So yes, we can be somewhat confident that sleep does improve the ability to remember. But how does it happen? If we knew that, our confidence in the the relationships would increase even more. Enter Marcos Frank and Sara Aton of the University of Pennsylvania School of Medicine.
In an article titled, Why Sleep Is Needed To Form Memories, (a more accurate title, IMO, would have emphasized the “how,” for that is what the study was about) we learn that the team successfully revealed the actual molecular changes involved that occur during sleep alone.
Frank said,
[W]hen the animal goes to sleep it’s like you’ve thrown a switch, and all of a sudden, everything is turned on that’s necessary for making synaptic changes that form the basis of memory formation. It’s very striking.
How did he know? How did he make this determination? Understanding the “how” is important. Let’s find out. Later on the article we come to this essential item.
The key cellular player in this process is a molecule called N-methyl D-aspartate receptor (NMDAR), which acts like a combination listening post and gate-keeper. It both receives extracellular signals in the form of glutamate and regulates the flow of calcium ions into cells.
What’s more, Frank reports,
these enzymes never really turned on until the animal had a chance to sleep.
Hmm. What does “never really turned on” mean? That the the states of activity aren’t just fully off and fully on?
That question aside, we now have a better understanding how sleep and memory formation are related. Does sleep influence memory? Yes. Because a “how” is being added to our understanding, our confidence that it does has grown.
