EEG waveforms for waking, non-REM sleep stages 1-4, and REM sleep.

Note that as we fall asleep, the fast, irregular, high-voltage, desynchronized EEG waves that typify waking are gradually replaced by slow, regular, high-voltage, synchronized EEG waves of deep, delta sleep.

"Synchronized" means that all the neurons are doing the same thing at the same time, yielding the undifferentiated neural activity, reduced cognition, and minimal arousal that occur during sleep.

One way to understand the effects of the Sounder Sleep System is to recognize that certain stimuli are acknowledged to have a "synchronogenic" effect. That is, they tend to induce synchronized brain activity. Soft, rhythmic music or lullabyes, rocking movements, and other rhythmic or predictable stimuli are common examples. In the Sounder Sleep System, we use our own movements and directed attention to produce synchronogenic stimuli for ourselves whenever needed.

In REM sleep, the brain is highly activated, and EEG waves are desynchronized, much as they are in waking. REM sleep is characterized by Rapid Eye Movements, unregulated blood pressure, postural atonia, sexual arousal, and heightened cognition in the form of dreams.