title: Ongoing network state controls the length of sleep spindles via inhibitory activity.
abstract: Sleep spindles are major transient oscillations of the mammalian brain. Spindles are generated in the thalamus; however, what determines their duration is presently unclear. Here, we measured somatic activity of excitatory thalamocortical (TC) cells together with axonal activity of reciprocally coupled inhibitory reticular thalamic cells (nRTs) and quantified cycle-by-cycle alterations in their firing in vivo. We found that spindles with different durations were paralleled by distinct nRT activity, and nRT firing sharply dropped before the termination of all spindles. Both initial nRT and TC activity was correlated with spindle length, but nRT correlation was more robust. Analysis of spindles evoked by optogenetic activation of nRT showed that spindle probability, but not spindle length, was determined by the strength of the light stimulus. Our data indicate that during natural sleep a dynamically fluctuating thalamocortical network controls the duration of sleep spindles via the major inhibitory element of the circuits, the nRT.
authors.affiliation: Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, 43 Szigony utca, Hungary. Electronic address: bartho@koki.hu.
authors.forename: Péter
authors.initials: P
authors.lastname: Barthó
authors.affiliation: Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, 43 Szigony utca, Hungary.
authors.forename: Andrea
authors.initials: A
authors.lastname: Slézia
authors.affiliation: Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, 43 Szigony utca, Hungary.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Mátyás
authors.affiliation: Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, 43 Szigony utca, Hungary.
authors.forename: Lejla
authors.initials: L
authors.lastname: Faradzs-Zade
authors.affiliation: Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1083, Budapest, 1068, 83-85 Szondi utca, Hungary; Péter Pázmány Catholic University, Faculty of Information Technology and Bionics, 1083, Budapest, 50/A Práter utca, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Ulbert
authors.affiliation: UCL Institute of Neurology, UCL Department of Neuroscience, Physiology, and Pharmacology, 21 University Street, London WC1E 6DE, UK.
authors.forename: Kenneth D
authors.initials: KD
authors.lastname: Harris
authors.affiliation: Laboratory of Thalamus Research, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083, Budapest, 43 Szigony utca, Hungary. Electronic address: acsady@koki.hu.
authors.forename: László
authors.initials: L
authors.lastname: Acsády
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D008297:Male; D057507:Mice, 129 Strain; D008822:Mice, Transgenic; D009415:Nerve Net / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012890:Sleep / Q000502:physiology*; D013788:Thalamus / Q000502:physiology*; D013997:Time Factors