title: Functional convergence of neurons generated in the developing and adult hippocampus.
abstract: The dentate gyrus of the hippocampus contains neural progenitor cells (NPCs) that generate neurons throughout life. Developing neurons of the adult hippocampus have been described in depth. However, little is known about their functional properties as they become fully mature dentate granule cells (DGCs). To compare mature DGCs generated during development and adulthood, NPCs were labeled at both time points using retroviruses expressing different fluorescent proteins. Sequential electrophysiological recordings from neighboring neurons of different ages were carried out to quantitatively study their major synaptic inputs: excitatory projections from the entorhinal cortex and inhibitory afferents from local interneurons. Our results show that DGCs generated in the developing and adult hippocampus display a remarkably similar afferent connectivity with regard to both glutamate and GABA, the major neurotransmitters. We also demonstrate that adult-born neurons can fire action potentials in response to an excitatory drive, exhibiting a firing behavior comparable to that of neurons generated during development. We propose that neurons born in the developing and adult hippocampus constitute a functionally homogeneous neuronal population. These observations are critical to understanding the role of adult neurogenesis in hippocampal function.
authors.affiliation: Fundación Instituto Leloir, Buenos Aires, Argentina.
authors.forename: Diego A
authors.initials: DA
authors.lastname: Laplagne
authors.forename: M Soledad
authors.initials: MS
authors.lastname: Espósito
authors.forename: Verónica C
authors.initials: VC
authors.lastname: Piatti
authors.forename: Nicolás A
authors.initials: NA
authors.lastname: Morgenstern
authors.forename: Chunmei
authors.initials: C
authors.lastname: Zhao
authors.forename: Henriette
authors.initials: H
authors.lastname: van Praag
authors.forename: Fred H
authors.initials: FH
authors.lastname: Gage
authors.forename: Alejandro F
authors.initials: AF
authors.lastname: Schinder
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000367:Age Factors; D000818:Animals; D004553:Electric Conductivity; D018728:Entorhinal Cortex / Q000166:cytology; D005071:Evoked Potentials / Q000502:physiology; D006624:Hippocampus / Q000166:cytology* / Q000254:growth & development* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology
chemical_list: D005680:gamma-Aminobutyric Acid