1. Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
2. These authors contributed equally to this work
3. Present addresses: Instituto de Investigaciones Bioquímicas Fundación Campomar, Av. Patricias Argentinas 435, (1405) Buenos Aires, Argentina (A.F.S.); Department of Psychology and Neuroscience Program, University of British Columbia Vancouver, British Columbia, V6T 1Z4, Canada (B.R.C.); Department of Neurosurgery, Stanford University, California 94305, USA (T.D.P.).

Correspondence to: Henriette van Praag^1,2 Correspondence should be addressed to H.v.P. (e-mail: Email: vanpraag@salk.edu).

Abstract

There is extensive evidence indicating that new neurons are generated in the dentate gyrus of the adult mammalian hippocampus, a region of the brain that is important for learning and memory^{1, 2, 3, 4, 5}. However, it is not known whether these new neurons become functional, as the methods used to study adult neurogenesis are limited to fixed tissue. We use here a retroviral vector expressing green fluorescent protein that only labels dividing cells, and that can be visualized in live hippocampal slices. We report that newly generated cells in the adult mouse hippocampus have neuronal morphology and can display passive membrane properties, action potentials and functional synaptic inputs similar to those found in mature dentate granule cells. Our findings demonstrate that newly generated cells mature into functional neurons in the adult mammalian brain.