Coordinated manner of action of the projections from monoaminergic cell groups, cholinergic and orexin neurons, produces arousal. Turning this arousal system off would result in producing sleep. There is an important role for the Ventrolateral Preoptic Nucleus (VLPO) to inhibit the arousal circuits during sleep. VLPO neurons are sleep active neurons [1-3]. Also, these neurons contain GABA and Galanin as inhibitory neurotransmitters. Such neurons receive afferents from monoaminergic systems. VLPO lesions would cause fragmented sleep and insomnia.