title: Young dentate granule cells mediate pattern separation, whereas old granule cells facilitate pattern completion.
abstract: Adult-born granule cells (GCs), a minor population of cells in the hippocampal dentate gyrus, are highly active during the first few weeks after functional integration into the neuronal network, distinguishing them from less active, older adult-born GCs and the major population of dentate GCs generated developmentally. To ascertain whether young and old GCs perform distinct memory functions, we created a transgenic mouse in which output of old GCs was specifically inhibited while leaving a substantial portion of young GCs intact. These mice exhibited enhanced or normal pattern separation between similar contexts, which was reduced following ablation of young GCs. Furthermore, these mutant mice exhibited deficits in rapid pattern completion. Therefore, pattern separation requires adult-born young GCs but not old GCs, and older GCs contribute to the rapid recall by pattern completion. Our data suggest that as adult-born GCs age, their function switches from pattern separation to rapid pattern completion.
authors.affiliation: Department of Biology, RIKEN-MIT Center for Neural Circuit Genetics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Nakashiba
authors.forename: Jesse D
authors.initials: JD
authors.lastname: Cushman
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Pelkey
authors.forename: Sophie
authors.initials: S
authors.lastname: Renaudineau
authors.forename: Derek L
authors.initials: DL
authors.lastname: Buhl
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: McHugh
authors.forename: Vanessa
authors.initials: V
authors.lastname: Rodriguez Barrera
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chittajallu
authors.forename: Keisuke S
authors.initials: KS
authors.lastname: Iwamoto
authors.forename: Chris J
authors.initials: CJ
authors.lastname: McBain
authors.forename: Michael S
authors.initials: MS
authors.lastname: Fanselow
authors.forename: Susumu
authors.initials: S
authors.lastname: Tonegawa
mesh_terms: D000375:Aging; D000818:Animals; D023902:Chromosome Pairing; D018891:Dentate Gyrus / Q000166:cytology* / Q000254:growth & development / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000235:genetics; D006624:Hippocampus / Q000502:physiology; D008568:Memory; D051379:Mice; D008822:Mice, Transgenic
chemical_list: D049452:Green Fluorescent Proteins