Characterization of neurons born and incorporated into a vocal control nucleus during avian song learning.

In male zebra finches, song learning is accompanied by the addition of new neurons to Area X, a nucleus necessary for normal song development. We examined whether Area X neurons born after 15 days post-hatch are recruited into the efferent pathway from Area X to the dorsolateral nucleus of the medial anterior thalamus (DLM). Our data suggest that the majority of these new Area X neurons are interneurons and that DLM-projecting neurons are incorporated into Area X prior to song learning.