Certain sleep stages are noted to improve an individual's memory, although this is task specific.

On the other hand, as encephalographic registrations of sleep stages were not made in this study, such a conclusion can only be tentative.

The deep sleep stages usually last about 30 minutes during the first cycle and decrease in duration during the night.

Finally, they demonstrated a reduced ability to wake up because of disturbances in their deep sleep stages.

In fact, different sleep stages are commonly characterized by their spectral content.

During the night, different patterns of spontaneous rhythms arise in what are called sleep stages.

Earlier sleep stages can occur simultaneously in both hemispheres.

By increasing this sleep stage, patients feel more refreshed in the morning.

Changes in the sleep stages occur when the activity curves of these neurons cross.

Most dreams occur during the sleep stage characterized by rapid eye movements.