Which sleep stage is associated with the predominance of theta activity?

The predominance of theta activity is most closely associated with REM sleep. During this stage, the brain exhibits a pattern that resembles wakefulness, yet the body is in a state of muscle atonia, which prevents movement. Theta waves are significant during the early stages of sleep as well, particularly in light sleep, but they are most prominent in REM sleep both in terms of frequency and intensity.

Moreover, REM sleep plays a crucial role in memory consolidation and emotional processing, which are enhanced by this specific brain wave activity. The interplay of theta waves and other brain rhythms during REM contributes to the vivid dreaming and cognitive processes associated with this stage.