title: Silencing CA3 disrupts temporal coding in the CA1 ensemble.
abstract: In addition to the place-cell rate code, hippocampal area CA1 employs a temporal code, both on the single-cell and ensemble level, to accurately represent space. Although there is clear evidence that this precise spike timing is organized by theta and gamma oscillations that are present in hippocampus, the circuit mechanisms underlying these temporal codes remain poorly understood. We found that the loss of CA3 input abolished temporal coding at the ensemble level in CA1 despite the persistence of both rate and temporal coding in individual neurons. Moreover, low gamma oscillations were present in CA1 despite the absence of CA3 input, but spikes associated with these periods carried significantly reduced spatial information. Our findings dissociate temporal coding at the single-cell (phase precession) and population (theta sequences) levels and suggest that CA3 input is crucial for temporal coordination of the CA1 ensemble code for space.
authors.affiliation: Laboratory for Circuit and Behavioral Physiology, RIKEN Brain Science Institute, Wakoshi, Saitama, Japan.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Middleton
authors.affiliation: Laboratory for Circuit and Behavioral Physiology, RIKEN Brain Science Institute, Wakoshi, Saitama, Japan.|Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan.
authors.forename: Thomas J
authors.identifier: 0000-0002-1243-5189
authors.initials: TJ
authors.lastname: McHugh
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D056547:CA1 Region, Hippocampal / Q000502:physiology*; D056654:CA3 Region, Hippocampal / Q000502:physiology*; D008297:Male; D008822:Mice, Transgenic; D008959:Models, Neurological; D017966:Pyramidal Cells / Q000502:physiology; D013826:Theta Rhythm / Q000502:physiology*