Light sleep is broken down into stages 1 and 2. The first stage is simply the act of transitioning from being awake to being asleep. It makes up less than 3% of your nightly sleep cycles.

The three main stages of the experiment of Whitmore et al. (2022). First, participants learned 80 face-name associations. Next, they slept while EEG was monitored to determine sleep stage ...

Now, researchers from Professor Jozsef Csicsvari's group at the Institute of Science and Technology Austria (ISTA) have probed the key roles of sleep stages in optimizing memory recollection.