Compare and contrast the neural systems that control slow-wave and REM sleep with regard to anatomy ...

Answer: Slow-wave sleep is produced by activity of neurons within the ventrolateral preoptic area (vlPOA), which act by inhibition of neural systems that promote wakefulness (e.g., NE within the locus coeruleus, histamine in the tuberomammillary nucleus, and serotonin within the raphe nuclei) to initiate sleep. When the sleep-waking flip-flop is in the awake state, sleep is prevented. In the sleep state, slow-wave sleep shifts to REM sleep via another flip-flop mechanism in which cells within the sublaterodorsal nucleus act as REM-ON cells while cells within the ventrolateral PAG act as a REM-OFF region. When the REM-ON cells are active, motor neurons of the spinal cord are inhibited, whereas tectal neurons generate rapid eye movements.