HCRT and narcolepsy: The orexin system plays a particularly important role in the normal expression of waking and sleep since its disruption underlies the sleep disorder narcolepsy with cataplexy in humans (Peyron et al., 2000; Thannickal et al., 2000) and produces a narcolepsy phenotype with unstable behavioral states, sleep attacks and cataplexy-like motor arrests in animals (Chemelli et al., 1999; Lin et al., 1999; Hara et al., 2001; Willie et al., 2003; Beuckmann et al., 2004; Mochizuki et al., 2004; Kalogiannis et al., 2011).