title: Sleep in the spider monkey (Ateles geoffroyi): A semi-restrictive, non-invasive, polysomnographic study.
abstract: The normal sleep patterns of the spider monkey (Ateles geoffroyi) have not been described yet. The objective of this study was to characterize the electrophysiological patterns, sleeping postures, and sleep-wake cycle in semi-restricted spider monkeys. Continuous 24-hr polysomnographic (PSG) recordings, involving simultaneous recording of non-invasive electroencephalographic (EEG), electro-oculographic (EOG), and electromyographic (EMG) activities, were carried out in captive monkeys living in outdoor rainforest enclosures. Electrode placement was done according to the human international 10-20 system. Specific behaviors displayed by monkeys during the sleep-wake cycles were correlated with the PSG recordings. The nycthemeral distribution of the sleep-wake cycle was also calculated. The results show that electrophysiological N-REM sleep patterns in spider monkeys are similar to those observed in other primates, including human beings. Furthermore, a vertical semi-fetal posture was observed during N-REM and REM sleep phases. The amount of nocturnal sleep was significantly higher than that of the diurnal period, showing that the spider monkey is a diurnal primate. An outstanding finding was the absence of muscular atonia during the spider monkey's REM sleep, which suggests that arboreal primates have developed a neuromuscular mechanism specialized for sleeping in a vertical posture.
authors.affiliation: Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana-Iztapalapa, Distrito Federal, México; Laboratorio de Sueño, Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría "Ramón de la Fuente Muñiz", Distrito Federal, México.
authors.forename: Manuel Alejandro
authors.initials: MA
authors.lastname: Cruz-Aguilar
authors.forename: Fructuoso
authors.initials: F
authors.lastname: Ayala-Guerrero
authors.forename: Anabel
authors.initials: A
authors.lastname: Jiménez-Anguiano
authors.forename: Ana María
authors.initials: AM
authors.lastname: Santillán-Doherty
authors.forename: Francisco
authors.initials: F
authors.lastname: García-Orduña
authors.forename: Javier
authors.initials: J
authors.lastname: Velázquez-Moctezuma
mesh_terms: D000818:Animals; D053819:Atelinae / Q000502:physiology*; D002940:Circadian Rhythm; D009129:Muscle Tonus; D017286:Polysomnography; D011187:Posture / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D014197:Trees
keywords: PSG; REM; muscular atonia; new world monkey