I had thought that sleep was restricted to chordates, and that other animals showed circadian periodicity in activity patterns, but not "sleep".
Has the Oxford group tested the Drosophila cell group for activation by the wide variety of compounds that work as general anesthetics across animals?  In particular do the steroid anesthetics such as pregnanolone preferentially activate these cells as might be expected by their exception to the Meyer Overton correlation of lipid solubility and anesthetic potency?
Interesting finding, but the generalization from flies to people is a stretch.