299, 411). Of note, increased and intensified NREM and decreased REM sleep depend on several factors, such as time of day, route, and dose of administration. For example, in rats, NREM sleep-increasing effects of IL-1 occur only within a small dose-window: lower doses of IL-1 increase NREM sleep without inducing fever; higher doses of IL-1 accompanied by fever increase and fragment NREM but decrease REM sleep; and even higher doses decrease both (412) (as reviewed in Ref. 300). The gene discussed is IL1B; the disease is Fever.