Learning-induced survival of new neurons depends on the cognitive status of aged rats.
Journal of Neuroscience. 2007-05-30; 27(22): 6037-6044
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1. J Neurosci. 2007 May 30;27(22):6037-44.
Learning-induced survival of new neurons depends on the cognitive status of aged
Drapeau E(1), Montaron MF, Aguerre S, Abrous DN.
(1)Institut National de la Santé et de la Recherche Médicale U862, Bordeaux
Neuroscience Research Center, University of Bordeaux 2, Bordeaux, France.
Aging is accompanied by an alteration of spatial memory, which has been related
to an alteration in hippocampal plasticity. Within the dentate gyrus, new neurons
are generated throughout the entire life of an individual. This neurogenesis
seems to play a role in hippocampal-mediated learning and learning-induced
changes in neurogenesis have been proposed to be involved in memory. However, in
aged rats, little is known on the influence of learning on the early development
of the adult-born neurons and on the possible involvement of learning-induced
changes in neurogenesis in age-related memory deficits. To address this issue, we
took advantage of the existence of spontaneous individual differences for
performances observed in aged subjects in the water maze. In this task, learning
can be divided into two phases, an early phase during which performances quickly
improve, and a late phase during which asymptotic levels of performances are
reached. We show that the influence of spatial learning on the survival of the
newly born cells depends on their birth date and the memory abilities of the aged
rats. In aged rats with preserved spatial memory, learning increases the survival
of cells generated before learning whereas it decreases survival of cells
produced during the early phase of learning. These results highlight the
importance of learning-induced changes in adult-born cell survival in memory.
Furthermore, they provide new insights on the possible neural mechanisms of aging
of cognitive functions and show that an alteration to the steps leading to
neurogenesis may be involved in the determination of individual memory abilities.
PMID: 17537975 [Indexed for MEDLINE]