HCRT and neurodegenerative disease: Furthermore, age-related loss of prepro-orexin mRNA production in the LH of rodents is accompanied by reduced orexinergic innervation in the hippocampus, basal forebrain, and locus coeruleus, brain regions associated with cognitive decline in neurodegenerative diseases (Zhang et al., 2005a,b; Downs et al., 2007; Stanley and Fadel, 2012).