Answer to Question 1
Answer: Certain aspects of REM sleep (paralysis, dreaming) appear to intrude into the daytime hours in a person with narcolepsy. Sleep attack is an overwhelming urge to sleep for a few minutes. During cataplexy, a person has paralysis while conscious, whereas during sleep, paralysis occurs just before or just after sleep. Hypnagogic hallucinations are dreams that occur during sleep paralysis. Narcolepsy involves damage to the brain hypocretin system.
Answer to Question 2
Answer: Slow-wave sleep is produced by activity of neurons within the ventrolateral preoptic area (vlPOA) that act by inhibition of neural systems that promote wakefulness. The vlPOA secretes GABA, which in turn inhibits transmitter systems that are key to arousal and wakefulness. These include norepinephrine within the locus coeruleus, histamine in the tuberomammillary nucleus, and serotonin within the raphe nuclei. Adenosine may promote sleep by GABA-mediated inactivation of acetylcholine neurons that promote arousal. Orexin (hypocretin) neurons promote wakefulness.