Sleep and dream

Q: What are the main stages of sleep in order?
A: Stage 1 → Stage 2 → Stage 3/4 (deep sleep) → REM → Repeat.

Q: What happens in Stage 1 sleep?
A: Light sleep, theta waves, hypnic jerks, easy to wake.

Q: What happens in Stage 2 sleep?
A: Sleep spindles and K-complexes; body slows down; light sleep.

Q: What are the features of Stage 3/4 sleep?
A: Deep sleep, delta waves, physical restoration, hard to wake.

Q: What is REM sleep?
A: Rapid eye movement, dreaming occurs, brain is active, body is paralysed.

Q: How do amplitude and frequency of brainwaves change through sleep?
A: As sleep deepens, amplitude increases and frequency decreases. REM is fast and low amplitude like waking brain.

Q: How long is the circadian sleep-wake cycle?
A: Approximately 24 hours.

Q: What controls the circadian rhythm?
A: The suprachiasmatic nucleus (SCN) in the hypothalamus.

Q: What is the Restoration Theory of sleep?
A: Sleep repairs the body and brain. Oswald: NREM restores the body, REM restores the brain.

Q: What is the Adaptive (Evolutionary) Theory?
A: Sleep keeps animals safe and conserves energy when they're not active.

Q: What are the three main dream theories?
A: 1. Freud's theory (wish fulfilment), 2. Activation-synthesis (random brain activity), 3. Information-processing (consolidates memories).

Q: When do most dreams occur?
A: During REM sleep, especially in the second half of the night.

Q: How many dreams do we have per night?
A: About 4–6 dreams per night.

Q: What is a lucid dream?
A: A dream where the person is aware they are dreaming and may control it.

Q: What is a daydream?
A: A spontaneous shift in attention away from the present, while awake.

Q: Name 3 effects of sleep deprivation.
A: Fatigue, poor concentration, mood swings, memory issues.

Q: What is insomnia?
A: Difficulty falling or staying asleep.

Q: What is sleepwalking?
A: Performing complex actions while still asleep, usually during deep sleep.

Q: What is narcolepsy?
A: A disorder causing sudden sleep attacks during the day.

Q: Give 3 sleep hygiene strategies.
A: 1. Keep a regular bedtime
2. Avoid screens before bed
3. Create a calm sleep environment