title: Subicular activation preceding hippocampal ripples in vitro.
abstract: Sharp wave-ripple complexes (SW-Rs), a transient form of high-frequency field oscillations observed in the hippocampus, are thought to mediate memory consolidation. They are initiated mainly in hippocampal CA3 area and propagate to the entorhinal cortex through the subiculum; however, little is known about how SW-Rs are initiated and propagate. Here, we used functional multineuronal calcium imaging to monitor SW-R-relevant neuronal activity from the subiculum at single-cell resolution. An unexpected finding was that a subset of subicular neurons was activated immediately before hippocampal SW-Rs. The SW-R-preceding activity was not abolished by surgical lesion of the CA1-to-subiculum projection, and thus, it probably arose from entorhinal inputs. Therefore, SW-Rs are likely to be triggered by entorhinal-to-CA3/CA1 inputs. Moreover, the subiculum is not merely a passive intermediate region that SW-Rs pass through, but rather, it seems to contribute to an active modification of neural information related to SW-Rs.
authors.affiliation: 1] Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan [2].
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Norimoto
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Takeyuki
authors.initials: T
authors.lastname: Miyawaki
authors.forename: Norio
authors.initials: N
authors.lastname: Matsuki
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ikegaya
mesh_terms: D000200:Action Potentials; D000818:Animals; D056547:CA1 Region, Hippocampal / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D018728:Entorhinal Cortex / Q000502:physiology*; D006624:Hippocampus / Q000502:physiology*; D008297:Male; D051379:Mice; D009474:Neurons / Q000502:physiology; D061848:Optical Imaging / Q000379:methods
chemical_list: D002118:Calcium
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