FOS Is Induced by Singing in Distinct Neuronal Populations in a Motor Network

Abstract

Mechanisms underlying the learned vocal behavior of songbirds were studied by examining expression of the protein product of the immediate early gene c-fos (Fos) in zebra finches. Auditory stimuli including the bird's own song did not induce Fos in the song system. In contrast, the motor act of singing induced Fos in two song sensorimotor nuclei, HVc and RA. This induction was independent of auditory feedback, since it occurred in deafened birds that sang. Double-labeling studies demonstrated that only one of the two sets of projection neurons in HVc expressed singing-related Fos. The motor-driven induction of Fos identifies functionally distinct cell populations in a network for singing and may point to sites of cellular plasticity necessary for song maintenance.

Differential expression of glutamate receptors in avian neural pathways for learned vocalization

“…Furthermore, singing induces expression of actionpotential-regulated genes in these nuclei with different patterns for different genes, and this has been found for all three vocal learning groups Kimpo and Doupe, 1997;Li and Jarvis, 2001; Wada and Jarvis, unpublished results). Neurotransmission of activity and the regulation of these activity-dependent genes are thought to occur by neurotransmitter release onto neurotransmitter receptors (Worley et al, 1990;Lerea, 1997;Clayton, 2000;Jarvis, 2004a).…”

“…NMDA receptors in mammals regulate activity-dependent induction of ZENK (an acronym for Zif-268, Egr-1, NGFI-A, and Krox-24) and c-fos synthesis in neurons (Lerea, 1997). As singing induces expression of these genes in cerebral vocal nuclei Kimpo and Doupe, 1997), our results suggest that the induction is likely mediated through NR1/NR2A receptors for all four large cerebral vocal nuclei, and additionally through NR1/ NR2B receptors for Area X (Fig. 2, NMDA panel).…”

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

“…and subsequently perfused with saline and a fixative (4% paraformaldehyde and 2.5% glutaraldehyde in 0.1 M PBS, pH 7.4). Free-floating sections (40 m) were prepared by using standard immunocytochemical techniques (17,19,21,23). The sections were placed in 0.1 M PBS (pH 7.4) and subsequently incubated in 0.3% H 2 O 2 in PBS for 15 min.…”

“…Subsequent studies suggest a dissociation between the neural substrates of production and perception of song (20). When an adult zebra finch male sings, there is neuronal activation in the song-control nuclei (20,21). However, when the bird hears a conspecific song without singing itself, there is no increased activation in these nuclei, but there is in other regions, including NCM and cHV (14)(15)(16)(17)(18)(19)(20).…”

Transgenic songbirds offer an opportunity to develop a genetic model for vocal learning

“…), and a zebra finch BAC library (31). Other molecular tools not developed specifically for songbirds have been used fruitfully in them, including quantification of immediate early genes to map pathway activation (32)(33)(34), laser capture microdissection to compare gene expression between cell types (35), and non-germline-mediated viral manipulation of gene expression to modify behavior (36). However, until now, the ability to manipulate gene expression by using germline transgenic technology has not been available for songbirds.…”