title: Catecholaminergic cell groups and vocal communication in male songbirds.
abstract: Birdsong is a species-typical vocal signal that facilitates reproduction and deters competitors. Song production is regulated by a clearly defined and specialized neural circuitry in which high concentrations of catecholamines are present. The nuclei within the song control circuit receive projections from catecholaminergic cell populations involved in attention, arousal and motivation, including periaqueductal gray (PAG), ventral tegmental area (VTA), locus coeruleus (LoC) and sub coeruleus (SC). Here, we examine whether catecholamine-containing neurons in these regions exhibit the immediate early gene, ZENK, during spontaneous, undirected song production in male zebra finches (Taeniopygia guttata). Males were assigned to "singing" or "silent" groups based on the total duration of spontaneous, undirected song produced within a 30 min period. We quantified the number of cells expressing both ZENK-ir and tyrosine hydroxylase (TH)-ir within the VTA, PAG, LoC and SC. The number of cells expressing co-localized ZENK and TH-ir was significantly elevated within the PAG in males that were singing compared to silent males. The number of cells expressing ZENK-ir alone was also elevated in the VTA and SC in singing males compared to silent males. Although ZENK expression is elevated in singing birds it does not positively correlate with the amount of singing produced. It is therefore likely that catecholaminergic PAG neurons are involved in motivational or attentional components of vocal expression rather than vocal motor output. Overall, our study is consistent with the hypothesis that PAG catecholamine-containing neurons as well as VTA and SC neurons play a role in vocal communication of male songbirds.
authors.affiliation: Johns Hopkins University Department of Psychological and Brain Sciences 3400 North Charles Street, Baltimore, MD 21211, USA. lynchks@jhu.edu
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Lynch
authors.forename: Bettina
authors.initials: B
authors.lastname: Diekamp
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Ball
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001933:Brain Stem / Q000166:cytology; D002395:Catecholamines / Q000378:metabolism*; D002452:Cell Count / Q000379:methods; D046369:Finches; D005786:Gene Expression Regulation / Q000502:physiology; D053400:High Vocal Center / Q000166:cytology*; D017874:Immediate-Early Proteins / Q000378:metabolism; D008297:Male; D009434:Neural Pathways / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D014828:Vocalization, Animal
chemical_list: D002395:Catecholamines; D017874:Immediate-Early Proteins; D014446:Tyrosine 3-Monooxygenase