P2.165 Thursday, Jan. 5 The Effects of Corticosterone Treatment on Song Complexity and HVC Size in the Male Zebra Finch SHAHBAZI, Mahin*; JIMENEZ, Pedro; CARRUTH, Laura L.; Georgia State University, Atlanta, GA; Autonomous University of Tlaxcala, Tlaxcala, Mexico; Georgia State University, Atlanta, GA firstname.lastname@example.org
Early developmental stress experienced by male zebra finches (Taeniopygia guttata) leads to a reduction of song complexity and decreased HVC (a song control nucleus) size in adulthood. HVC is required for learning and production of song, and song complexity is an important factor in mate choice. The stress-induced reduction in song complexity and HVC size indicates a connection between the hypothalamic-pituitary-adrenal axis, song control brain regions and singing behavior, however the mechanisms underlying these effects are unknown. We are investigating the role of glucocorticoid receptors (GRs) and stress on the development of the avian song system. Our previous work demonstrated that glucocorticoid receptor-like immunoreactive-neurons (GR-like ir-neurons) were localized in the brains of male zebra finches collected from P10 (post-hatch day 10, song nuclei formed), and adult birds (post-hatch day 90 or older, sexually mature and singing crystallized songs). We have quantified the number of cytoplasmic and nuclear GR in each brain region in P10 and adult males. In addition, adult males that received chronic corticosterone (Cort) implants on P5 had altered HVC volume when measured. Songs of chronic Cort implanted vs. control birds were recorded and had a significant reduction in song complexity. The mechanism of how Cort treatment influences HVC size, and ultimately song complexity, has yet to be determined. Supported by GSU Neuroscience Institute and the Brains & Behavior program.