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Christelle Rochefort, Postdoctoral Fellow (until June 2007).

Since a few decades it is known that discrete areas of the adult brain contain stem or progenitors cells that divide and give rise to neuronal precursors that migrate and incorporate into specific brain regions[1]. This phenomenon, called adult neurogenesis, has been described in a broad range of species, including humans [2]. In the zebra finch, new neurons coming from the ventricular zone, a discrete area lining the lateral ventricle, migrate throughout the anterior forebrain and integrate into two nuclei of the song system, the HVC, that controls song production, and Area X, that is related to song learning [3]. Neurogenesis in HVC has been well characterized but fewer data exist regarding neurogenesis in Area X [4]. By using immunohistochemical techniques, confocal analyses, stereotaxic injections of fluorescent neuronal tracer and gene silencing methods via retroviral injection, we are conducting several projects with the aim of identifying factors involved in the regulation of neuronal recruitment into Area X.

(1) Alvarez-Buylla A, Nottebohm F (1988).Migration of young neurons in adult avian brain. Nature 335:353-354. (2) Abrous DN, Koehl M, Le Moal M (2005) Adult neurogenesis: from precursors to network and physiology. Physiol Rev 85:523-569. (3) Sohrabji F, Nordeen EJ, Nordeen KW (1990) Selective impairment of song learning following lesions of a forebrain nucleus in the juvenile zebra finch. Behav Neural Biol 53:51-63. (4) Wilbrecht L, Kirn JR (2004) Neuron addition and loss in the song system: regulation and function. Ann N Y Acad Sci 1016:659-683.