Tip of the information-processing iceberg--The unconscious mind
During strong mental engagement, the brain exhibits low amplitude and fast, irregular beta waves. An awake person involved in a conversation shows beta activity.
When an individual closes his eyes but remains awake, his brain
During early, light sleep (stages 1-2) the brain enters a high-amplitude, slow, regular wave form called theta waves. A person who is daydreaming shows theta activity.
During deepest sleep (stages 3-4), brain activity slows down. There are large-amplitude, slow delta waves.
After reaching the deepest sleep stage (4), the sleep cycle starts moving backward towards stage 1. Although still asleep, the brain engages in low- amplitude, fast and regular beta waves much like
A person during this sleep exhibits Rapid Eye Movements
With each 90-minute cycle, stage 4 sleep decreases and...
Occur during first few hours of Stage 4
Not nightmares (not during REM)
May sit up, walk around, talk incoherently
Doubling of heart rate and breathing, appear terrified
Seldom awaken or remember
Sometimes incorporates traces and preoccupations of the day:
Sensory stimuli in our environment may also be incorporated into dreams
Why do All dream researchers believe we need REM sleep?