A re-examination of ZENK expression following hetero- and conspecific playback in the zebra finch auditory forebrain

Abstract

Zebra finches (Taeniopygia guttata) are one of the most sexually dimorphic songbirds used as model species, not only in appearance but also in vocal production; while males produce both calls and songs, the females only produce calls. This dimorphism in the zebra finch provides a means to contrast the auditory perception of vocalizations produced by songbird species of varying degrees of relatedness in a dimorphic species to that of a monomorphic species, i.e., the black-capped chickadee (Poecile atricapillus). In this study I looked at neuronal expression after playback of acoustically similar hetero- and conspecific calls in male and female zebra finches, as a follow-up study to previous work conducted by Avey and colleagues (2014) on black-capped chickadees. An immediate early gene (IEG), ZENK, was measured in two auditory areas of the forebrain (caudomedial mesopallium, CMM, and caudomedial nidopallium, NCM). In black-capped chickadees, there was no significant difference in expression for calls produced by other species that were phylogenetically distant. In the current study, I found no difference in ZENK expression in either male or female zebra finches regardless of playback conditions. My results suggest that, similar to black-capped chickadees, zebra finch IEG expression in the CMM and NCM is related to the acoustic similarity of vocalizations and not the phylogenetic relatedness of the species producing the vocalizations.