Learning? Sleep on it, but not too deep

People have long been fascinated with the idea of learning while asleep - and now, scientists may have found some proof of viability.

A recent study found that the human brain can learn in certain phases of shut-eye: Rapid eye movement (REM) and N2, researchers wrote in the journal Nature Communications.

There are five stages of sleep - ranging from wakefulness through three stages (N1 to N3) of non-REM sleep to REM itself, which is the phase during which we dream, and is characterised by eyes darting back and forth.

The researchers wired 23 volunteers up to brain monitors that track and record brain wave patterns, and played them recordings of sound patterns while they slept.

They were then tested on how well they could remember the simple compositions after they woke up.

The team "observed a sharp distinction between light non-REM - N2 - sleep, during which learning was possible, and deep non-REM sleep - or N3 - during which learning was suppressed", said a press summary by the journal.

Upon waking, the participants who heard the sounds during N3 sleep found the same patterns even harder to re-learn than to pick up completely new ones.

This supported theories that N3 sleep serves to unclutter the memory, said the researchers. - AFP