Increased ponto-geniculo-occipital (PGO) wave frequency following central administration of neostigmine.

In all mammals so far investigated the occurrence of ponto-geniculo-occipital (PGO) waves precedes the onset and maintenance of desynchronized (D) sleep. As unitary electrographic events, PGO waves provide an index for quantitative evaluation of physiological D sleep or the D sleep-like state evoked by centrally administered acetylcholinesterase inhibitors. The present study characterized PGO wave frequency and time course following central administration of neostigmine bromide (Neo). The results show that Neo produced a dose-dependent increase in PGO wave frequency and time course when injected into brainstem regions other than areas containing putative PGO wave generating neurons. These results support the concept that PGO waves and D sleep are generated by an anatomically distributed network of cholinoceptive neurons.