Final answer:
The alpha wave is characteristic of stage 1 sleep, associated with low amplitude and a frequency of 8-12 Hz, indicating a relaxed state.
Step-by-step explanation:
The alpha wave is characteristic of stage 1 sleep. During this initial stage of sleep, which marks the transition from wakefulness to sleep, there is a marked decrease in both overall muscle tension and core body temperature.
The brain wave activity associated with this stage includes alpha waves, which have a relatively low amplitude and a frequency of 8-12 Hz, indicative of a very relaxed state that is more synchronized compared to the higher frequency and lower amplitude beta waves present during wakefulness.
As one continues through stage 1 sleep, theta waves begin to appear, which are even lower in frequency.