“…In these cases, during periods of sleep the forebrain generates a sleep-like state characterized by periods of high voltage EEG, independent of the brainstem, that shows periods of phasic activity similar to that seen in REM sleep [Jouvet, 1962;Siegel, 2000]. Moreover, lesions of the rostral brainstem cholinergic cell groups in adult mammals [McGinty, 1969], or blockade of all cholinergic cell groups by atropine administration [Szymusiak et al, 1994], produces periods of REM sleep with high voltage EEG [Shoham and Teitelbaum, 1982]. Secondly, juvenile mammals show a similar pattern of brain activity during sleep, i.e., high voltage EEG and phasic brainstem activity [McGinty et al, 1977;Frank and Heller, 1997;Siegel, 1999].…”