title: Membrane Potential Dynamics of CA1 Pyramidal Neurons during Hippocampal Ripples in Awake Mice.
abstract: Ripples are high-frequency oscillations associated with population bursts in area CA1 of the hippocampus that play a prominent role in theories of memory consolidation. While spiking during ripples has been extensively studied, our understanding of the subthreshold behavior of hippocampal neurons during these events remains incomplete. Here, we combine in vivo whole-cell and multisite extracellular recordings to characterize the membrane potential dynamics of identified CA1 pyramidal neurons during ripples. We find that the subthreshold depolarization during ripples is uncorrelated with the net excitatory input to CA1, while the post-ripple hyperpolarization varies proportionately. This clarifies the circuit mechanism keeping most neurons silent during ripples. On a finer timescale, the phase delay between intracellular and extracellular ripple oscillations varies systematically with membrane potential. Such smoothly varying delays are inconsistent with models of intracellular ripple generation involving perisomatic inhibition alone. Instead, they suggest that ripple-frequency excitation leading inhibition shapes intracellular ripple oscillations.
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Brad K
authors.initials: BK
authors.lastname: Hulse
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Laurent C
authors.initials: LC
authors.lastname: Moreaux
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Evgueniy V
authors.initials: EV
authors.lastname: Lubenov
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Division of Engineering and Applied Science, California Institute of Technology, Pasadena, CA 91125, USA; Computation and Neural Systems Program, California Institute of Technology, Pasadena, CA 91125, USA. Electronic address: thanos@caltech.edu.
authors.forename: Athanassios G
authors.initials: AG
authors.lastname: Siapas
mesh_terms: D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D056547:CA1 Region, Hippocampal / Q000166:cytology*; D064026:Calbindins / Q000378:metabolism; D008239:Lysine / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology; D017711:Nonlinear Dynamics; D010320:Parvalbumins / Q000378:metabolism; D018408:Patch-Clamp Techniques; D017966:Pyramidal Cells / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*
chemical_list: D064026:Calbindins; D010320:Parvalbumins; C013411:biocytin; D008239:Lysine