Molecular mapping of brain areas involved in parrot vocal communication

Auditory and vocal regulation of gene expression occurs in separate discret e regions of the songbird brain. Here we demonstrate that regulated gene ex pression also occurs during vocal communication in a parrot, belonging to a n order whose ability to learn vocalizations is thought to have evolved ind ependently of songbirds. Adult male budgerigars (Melopsittacus undulatus) w ere stimulated to vocalize with playbacks of conspecific vocalizations (war bles), and their brains were analyzed for expression of the transcriptional regulator ZENK. The results showed that there was distinct separation of b rain areas that had hearing- or vocalizing-induced ZENK expression. Hearing warbles resulted in ZENK induction in large parts of the caudal medial for ebrain and in 1 midbrain region, with a pattern highly reminiscent of that observed in songbirds. Vocalizing resulted in ZENK induction in nine brain structures, seven restricted to the lateral and anterior telencephalon, one in the thalamus, and one in the midbrain, with a pattern partially reminis cent of that observed in songbirds. Five of the telencephalic structures ha d been previously described as part of the budgerigar vocal control pathway . However, functional boundaries defined by the gene expression patterns fo r some of these structures were much larger and different in shape than pre viously reported anatomical boundaries. Our results provide the first funct ional demonstration of brain areas involved in vocalizing and auditory proc essing of conspecific sounds in budgerigars. They also indicate that, wheth er or not vocal learning evolved independently, some of the gene regulatory mechanisms that accompany learned vocal communication are similar in songb irds and parrots. J. Comp. Neurol. 419:1-31, 2000. (C) 2000 Wiley-Liss, Inc .