title: Optogenetic activation of septal cholinergic neurons suppresses sharp wave ripples and enhances theta oscillations in the hippocampus.
abstract: Theta oscillations in the limbic system depend on the integrity of the medial septum. The different populations of medial septal neurons (cholinergic and GABAergic) are assumed to affect different aspects of theta oscillations. Using optogenetic stimulation of cholinergic neurons in ChAT-Cre mice, we investigated their effects on hippocampal local field potentials in both anesthetized and behaving mice. Cholinergic stimulation completely blocked sharp wave ripples and strongly suppressed the power of both slow oscillations (0.5-2 Hz in anesthetized, 0.5-4 Hz in behaving animals) and supratheta (6-10 Hz in anesthetized, 10-25 Hz in behaving animals) bands. The same stimulation robustly increased both the power and coherence of theta oscillations (2-6 Hz) in urethane-anesthetized mice. In behaving mice, cholinergic stimulation was less effective in the theta (4-10 Hz) band yet it also increased the ratio of theta/slow oscillation and theta coherence. The effects on gamma oscillations largely mirrored those of theta. These findings show that medial septal cholinergic activation can both enhance theta rhythm and suppress peri-theta frequency bands, allowing theta oscillations to dominate.
authors.affiliation: Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102; Center for Interdisciplinary Research in Biology, Institut National de la Santé et de la Recherche Médicale U1050, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241, Collège de France, F-75005 Paris, France;
authors.forename: Marie
authors.initials: M
authors.lastname: Vandecasteele
authors.affiliation: Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102; Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083, Budapest, Hungary;
authors.forename: Viktor
authors.initials: V
authors.lastname: Varga
authors.affiliation: Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102; Neuroscience Institute, School of Medicine, New York University, New York, NY 10016; and MTA-SZTE "Momentum" Oscillatory Neuronal Networks Research Group, Department of Physiology, University of Szeged, H-6720, Szeged, Hungary.
authors.forename: Antal
authors.initials: A
authors.lastname: Berényi
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083, Budapest, Hungary;
authors.forename: Edit
authors.initials: E
authors.lastname: Papp
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083, Budapest, Hungary;
authors.forename: Péter
authors.initials: P
authors.lastname: Barthó
authors.affiliation: Center for Interdisciplinary Research in Biology, Institut National de la Santé et de la Recherche Médicale U1050, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7241, Collège de France, F-75005 Paris, France;
authors.forename: Laurent
authors.initials: L
authors.lastname: Venance
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083, Budapest, Hungary;
authors.forename: Tamás F
authors.initials: TF
authors.lastname: Freund
authors.affiliation: Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, NJ 07102; Neuroscience Institute, School of Medicine, New York University, New York, NY 10016; and Gyorgy.Buzsaki@nyumc.org.
authors.forename: György
authors.initials: G
authors.lastname: Buzsáki
mesh_terms: D000758:Anesthesia; D000818:Animals; D001522:Behavior, Animal; D059329:Cholinergic Neurons / Q000502:physiology* / Q000528:radiation effects; D006624:Hippocampus / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D008822:Mice, Transgenic; D009043:Motor Activity / Q000528:radiation effects; D062308:Optogenetics; D010775:Photic Stimulation; D012686:Septal Nuclei / Q000502:physiology* / Q000528:radiation effects; D013826:Theta Rhythm / Q000502:physiology* / Q000528:radiation effects
keywords: acetylcholine; channelrhodopsin-2; in vivo electrophysiology; silicon probe