Fig. 1.

Dorsal view of the zebra finch brain showing the intracortical pathway from lMAN to RA on both sides; each pathway is strictly ipsilateral. lMAN and RA form part of the neural substrate for learned vocal behavior in oscine passerine birds and are necessary for normal vocal development (Nottebohm et al., 1976; Bottjer et al., 1984). Bilateral lMAN lesions (each marked with anX) were made to obtain a bilateral deafferentation of RA. Infusions of neurotrophin were made into left RA, and right RA served as a control for the effects of removing afferent input. lMAN, Lateral magnocellular nucleus of the anterior neostriatum; RA, robust nucleus of the archistriatum.