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. Author manuscript; available in PMC: 2022 Jan 15.
Published in final edited form as: Nature. 2005 Oct 27;437(7063):1264–1271. doi: 10.1038/nature04285

Figure 1 |. Distribution of some key sleep-regulating neuronal populations plotted on a sagittal section of a rat brain97.

Figure 1 |

Circles indicate ‘REM sleep off’ neurons; purple represents serotonergic neurons (located on the midline), orange represents adrenergic or noradrenergic neurons, blue represents histaminergic neurons, red represents hypocretinergic (orexinergic) neurons. Squares indicate ‘sleep on’ neurons. The green star indicates ‘REM sleep on’ neurons. The area shaded in grey is both necessary and sufficient for REM sleep generation. The area shaded in yellow is both necessary and sufficient for NREM sleep generation. In the intact animal both REM sleep and NREM sleep involve interactions between brainstem and forebrain structures. Vlpo, ventrolateral preoptic area; Mpo, median preoptic.