DRUGS AND THE SLEEP-WAKEFULNESS CONTINUUM

The circadian cycle of sleep and wakefulness in humans is controlled b y the activity of many neurotransmitters. Studies of the effects of dr ugs on the central nervous system have elucidated some of the mechanis ms that may be involved. Some transmitters are concerned with the basi c control of sleep and wakefulness, influencing both alertness during the day and the pattern of nocturnal sleep. On the other hand, there a re other transmitters that appear to be concerned primarily with the m anifestation of wakefulness and vigilance, without a direct role in th e process of sleep.