title: Monosynaptic inputs to new neurons in the dentate gyrus.
abstract: Adult hippocampal neurogenesis is considered important for cognition. The integration of newborn dentate gyrus granule cells into the existing network is regulated by afferent neuronal activity of unspecified origin. Here we combine rabies virus-mediated retrograde tracing with retroviral labelling of new granule cells (21, 30, 60, 90 days after injection) to selectively identify and quantify their monosynaptic inputs in vivo. Our results show that newborn granule cells receive afferents from intra-hippocampal cells (interneurons, mossy cells, area CA3 and transiently, mature granule cells) and septal cholinergic cells. Input from distal cortex (perirhinal (PRH) and lateral entorhinal cortex (LEC)) is sparse 21 days after injection and increases over time. Patch-clamp recordings support innervation by the LEC rather than from the medial entorhinal cortex. Mice with excitotoxic PRH/LEC lesions exhibit deficits in pattern separation but not in water maze learning. Thus, PRH/LEC input is an important functional component of new dentate gyrus neuron circuitry.
authors.affiliation: Neuroplasticity and Behavior Unit, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
authors.forename: Carmen
authors.initials: C
authors.lastname: Vivar
authors.affiliation: Neuroplasticity and Behavior Unit, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Potter
authors.affiliation: Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
authors.forename: Jiwon
authors.initials: J
authors.lastname: Choi
authors.affiliation: Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Neuroplasticity and Behavior Unit, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Stringer
authors.affiliation: Systems Neurobiology Laboratories, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Callaway
authors.affiliation: Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA.
authors.forename: Fred H
authors.initials: FH
authors.lastname: Gage
authors.affiliation: Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.
authors.forename: Hoonkyo
authors.initials: H
authors.lastname: Suh
authors.affiliation: Neuroplasticity and Behavior Unit, Laboratory of Neurosciences, Intramural Research Program, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA.
authors.forename: Henriette
authors.initials: H
authors.lastname: van Praag
mesh_terms: D000818:Animals; D018891:Dentate Gyrus / Q000166:cytology*; D004594:Electrophysiology; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D009474:Neurons / Q000378:metabolism* / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology