Stage 1 sleep is primarily dominated by which type of brain wave?

Stage 1 sleep is characterized by the presence of theta waves. During this initial stage of sleep, which serves as a transition between wakefulness and deeper sleep, the brain begins to produce these slower frequency waves. Theta waves typically have a frequency of about 4 to 8 Hz and are associated with light sleep, relaxation, and the onset of sleep.

As individuals progress into deeper stages of sleep, particularly Stage 3, delta waves become more prominent, while alpha waves are more commonly observed during relaxed wakefulness and not during sleep itself. Gamma waves, which are associated with higher cognitive functioning and alertness, are also not characteristic of Stage 1 sleep. Thus, the presence of theta waves during this stage of sleep is what makes them primarily dominant.