Infants produce sleep spindles every 10 second, whether in REM or non-REM sleep. Sleep spindles and twitching are synchronized, allowing for twitch reactions to occur during non-REM sleep in infants.
The reactivation of learned material during slow oscillation/sleep spindle complexes, and the precision of SO-spindle coupling predicts how strong a memory will be reactivated in the brain.
NMDA receptor hypofunction is involved in the reduction of sleep spindles and delta oscillations, which appear in the brain during deep natural sleep. Findings confirm the role NMDA receptors play in sleep disorders that accompany psychotic states.