title: Neocortical 40 Hz oscillations during carbachol-induced rapid eye movement sleep and cataplexy.
abstract: Higher cognitive functions require the integration and coordination of large populations of neurons in cortical and subcortical regions. Oscillations in the gamma band (30-45 Hz) of the electroencephalogram (EEG) have been involved in these cognitive functions. In previous studies, we analysed the extent of functional connectivity between cortical areas employing the 'mean squared coherence' analysis of the EEG gamma band. We demonstrated that gamma coherence is maximal during alert wakefulness and is almost absent during rapid eye movement (REM) sleep. The nucleus pontis oralis (NPO) is critical for REM sleep generation. The NPO is considered to exert executive control over the initiation and maintenance of REM sleep. In the cat, depending on the previous state of the animal, a single microinjection of carbachol (a cholinergic agonist) into the NPO can produce either REM sleep [REM sleep induced by carbachol (REMc)] or a waking state with muscle atonia, i.e. cataplexy [cataplexy induced by carbachol (CA)]. In the present study, in cats that were implanted with electrodes in different cortical areas to record polysomnographic activity, we compared the degree of gamma (30-45 Hz) coherence during REMc, CA and naturally-occurring behavioural states. Gamma coherence was maximal during CA and alert wakefulness. In contrast, gamma coherence was almost absent during REMc as in naturally-occurring REM sleep. We conclude that, in spite of the presence of somatic muscle paralysis, there are remarkable differences in cortical activity between REMc and CA, which confirm that EEG gamma (≈40 Hz) coherence is a trait that differentiates wakefulness from REM sleep.
authors.affiliation: Laboratorio de Neurobiología del Sueño, Facultad de Medicina, Departamento de Fisiología, Universidad de la República, General Flores 2125, 11800, Montevideo, Uruguay.
authors.forename: Pablo
authors.initials: P
authors.lastname: Torterolo
authors.affiliation: Laboratorio de Neurobiología del Sueño, Facultad de Medicina, Departamento de Fisiología, Universidad de la República, General Flores 2125, 11800, Montevideo, Uruguay.
authors.forename: Santiago
authors.initials: S
authors.lastname: Castro-Zaballa
authors.affiliation: Laboratorio de Neurobiología del Sueño, Facultad de Medicina, Departamento de Fisiología, Universidad de la República, General Flores 2125, 11800, Montevideo, Uruguay.
authors.forename: Matías
authors.initials: M
authors.lastname: Cavelli
authors.affiliation: WebSciences International and UCLA School of Medicine, Los Angeles, CA, USA.
authors.forename: Michael H
authors.initials: MH
authors.lastname: Chase
authors.affiliation: Laboratorio de Neurobiología del Sueño, Facultad de Medicina, Departamento de Fisiología, Universidad de la República, General Flores 2125, 11800, Montevideo, Uruguay.
authors.forename: Atilio
authors.initials: A
authors.lastname: Falconi
mesh_terms: D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D002385:Cataplexy / Q000139:chemically induced / Q000503:physiopathology*; D002415:Cats; D018679:Cholinergic Agonists / Q000494:pharmacology*; D004569:Electroencephalography / Q000379:methods; D019579:Neocortex / Q000187:drug effects; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D011149:Pons / Q000187:drug effects / Q000502:physiology; D012895:Sleep, REM / Q000187:drug effects*; D014851:Wakefulness / Q000187:drug effects
chemical_list: D018679:Cholinergic Agonists; D002217:Carbachol
keywords: cat; electroencephalogram; gamma; narcolepsy; nucleus pontis oralis; reticular formation