Localized neuronal activation in the zebra finch brain is related to the strength of song learning

Songbirds (Oscines) learn their songs from a tutor. It is not known where i n the brain the memories of these learned sounds are stored. Recent evidenc e suggests that song perception in songbirds involves neuronal activation i n brain regions that have not traditionally been implicated in the control of song production or song learning, notably the caudal part of the neostri atum (NCM) and of the hyperstriatum ventrale. Zebra finch males (Taeniopygi a guttata castanotis) were reared without their father and exposed to a tap e-recorded song during the sensitive period for song learning. When, as adu lts, they were reexposed to the tutor song, the males showed increased expr ession of the protein products of the immediate early genes egr-1 (ZENK) an d c-fos in the NCM and caudal hyperstriatum ventrale, but not in the conven tional "song-control nuclei." The strength of the immediate early gene resp onse (which is a reflection of neuronal activation) in the NCM correlated s ignificantly and positively with the number of song elements that the birds had copied from the tutor song. These results show localized neural activa tion in response to tutor song exposure that correlates with the strength o f song learning.