To sleep, perchance to learn

Trouble holding on to your memories? A bad night’s kip might be to blame. planetchopstick/Flickr

So here it is, another morning. Another day of yawns. Another day of … oh … what was I saying?

We all know that if you don’t get a good night’s sleep, you don’t function properly during the day. It could be that you can’t string two coherent sentences together. And it could be far more serious.

Sleepiness and fatigue are leading causes of road crashes and workplace accidents.

But researchers, myself included, are now showing that sleep not only plays a vital role in supporting normal daytime functioning: it’s important for committing to memory the lessons we have learnt during the day.

In other words: bad sleep equals bad memory.

Procedural skill learning (whether that be studying a language, chopping wood or learning to drive a car) in particular has been shown to be sleep-dependent.

Significant improvements in such tasks are only seen if one sleeps between learning the procedure and retesting.

Beyond basic procedural tasks, new research has shown that our capacity to remember emotional events and our ability to find creative solutions to mathematical puzzles (i.e. creative insight) are also sleep-dependent.

This does seem to make sense as many dreams are highly emotional and many artistic and scientific creations are inspired by dreams (e.g. The tune for Yesterday came to Paul McCartney in a dream; Otto Loewi’s Nobel Prize winning work on chemical neurotransmission was inspired by a dream).

Recently, researchers at the University of California, Berkeley, have found bursts of brain waves known as “sleep spindles” may be networking between key regions of the brain to clear a path for learning.

They provided strong evidence that sleep may facilitate brain plasticity, the mechanism whereby lasting structural and/or functional neuronal changes occur in the brain in response to ongoing experience.

In other words, our brains physically change when we sleep, being shaped by our experiences of the previous day.

The research I’m involved in at Monash University has found new evidence to suggest this physical change in the brain during sleep is vitally important for a healthy mind and normal daytime functioning.

So much so that even small disruptions to sleep can cause observable deficits in cognitive function, learning and memory.

Currently, we are investigating learning and memory processes of people with sleep disorders. We’ve also shown that as little as one disrupted night’s sleep can be enough to affect performance the following day in people without sleep disorders.

Which you most likely knew, of course, unless a dodgy night of Z’s made you forget.