Sleep and Dreaming

Question 1

Sleep Stages

beta, alpha, theta, delta (batd)

Answer 1

1. Beta waves = alert, fully awake state
2. Alpha waves = awake, rested, relaxed state S1
3. Theta waves = deep relaxation, light sleep S2
4. Delta waves = deep sleep.

Sleep stages 1-4 are called NREM (non-REM) sleep.

• Immediately before falling asleep, the person is drowsy which is alpha waves.
• As the person falls asleep, Stage 1 sleep begins.
  
  • alpha replaced by theta waves which are greater in amplitude and slower in frequency than alpha.
• Stage 2 = theta waves predominate but are interrupted by bursts of sleep spindles (rapid, rhythmic brain-wave activity) and K complexes (large negative wave followed by a smaller positive one).
• Stage 3 = large, slow delta waves appear.
• Stage 4 = delta waves dominate
• Stage 3 and 4 are called ‘slow-wave sleep’.

Stage 5: REM most vivid and elaborate dreams. remember dream if woken during REM but not after.

• EEG pattern is similar to stage 1-2, phsiological resembles awake state, HR and respiration rates are fast and irregular, sex arousal.
• However, they are in deep sleep during this stage. Active or paradoxical sleep!

Sleep passes through all 5 stages about every 90-100 minutes.

stage 3-4 occur in early part of sleep period, but REM periods increase in length as the night progresses.

Question 2

Sleep Patterns over Lifespan

Answer 2

Sleep patterns vary with age.

infants: begin with REM, changes to NREM (4 stages not until 6 months of age).

REM/NREM switch about 3 months of age, and total sleep time, stage 4 sleep, and REM sleep all decrease from childhood to adulthood.

newborn’s REM is 50% but drops to 30% by 6 months, to 20% with adults.

older adults DO NOT require less sleep than younger adults, but older folks have more trouble falling asleep, awaken more often in night, adn have advanced sleep phase (ASP) which is ashift in the timing of sleep of going to bed and waking up earlier.

Question 3

Sleep Deprivation

Answer 3

1. Short-Term sleep deprivation (under 48 hours) only mild detrimental impact, but longer periods vary from person to person, ranges from mood changes, to forgetfulness to disorientation and hallucination.
2. Chronic sleep restriction = decrements in cognitive tasks, speed of processing, working memory and sustained attention or complex information processing.
   
   1. cognitive processes for safe driving are especially sensitive to inadequate sleep and rates of accidents/fatalities are similar to alcohol related accidents.
3. REM deprivation not associated with significan abnormalities, but inability to retain newly learned information.
4. REM rebound occures afterwards to make up for lost REM periods.