Compare the characteristics of non-REM sleep with that of REM sleep.

Answer: Non-REM consists of four stages: stage 1 contains alpha activity (812 Hz) and theta activity (3.57.5 Hz); stage 2 contains sleep spindles (1214 Hz) but not alpha activity; stages 3 and 4 contain more delta activity ( less than 3.5 Hz). Muscle activity is present during non-REM sleep, but not REM sleep. In REM sleep, the EEG shifts back to a beta wave form (1330 Hz). In REM sleep, there are regular movements of the eyes, signs of genital activity, and dreaming. Non-REM dreams can be frightening (stage 4 night terrors).