TitleNeural discrimination of vocal communication signals in the avian auditory system
NameYoder, Kathleen Marie (author), Vicario, David S (chair), McGann, John (internal member), Kusnecov, Alexander (internal member), Ball, Gregory (outside member), Rutgers University, Graduate School - New Brunswick,
Zebra finch--Vocalization ,
Sexual dimorphism (Animals) ,
Sound production by animals--Sex differences
DescriptionSongs are learned in songbirds, much as speech is acquired in human infants, and serve social and reproductive functions. In most songbirds studied to date, males produce learned vocalizations while females do not and the male brain contains a more developed forebrain vocal control pathway. Males use song both in interactions with other males and in courtship displays to varying degrees in different species. In the zebra finch, the male sings to court females, who do not sing, but use this signal in the process of mate selection. Thus this species provides a model of sexual dimorphism in the use of song. An avian forebrain auditory area, NCM, seems to be specialized to discriminate and remember the unique songs of other individuals, through a process of stimulus-specific adaptation, but sex differences in NCM function have not been described. The present study compares neurophysiological responses recorded in NCM of adult male and female zebra finches that were either raised in the general aviary by their parents, or reared in individual isolation with an artificial song tutor. Extra-cellular multi-unit recordings were made at multiple sites bilaterally in NCM of awake, restrained adult birds during song playback to assess auditory responses, stimulus-specific adaptation, preference for conspecific song, and song recognition memory for the tutor song as well as songs heard in adulthood. In a subset of these birds, estradiol levels were manipulated pharmacologically to compare the role of this hormone – which is known to be synthesized in the brain - in auditory responses in the two sexes. The results in untreated birds show differences between males and females in adaptation to song playback in NCM, although absolute responses do not differ between the sexes. Estradiol depletion in both males and females interfered with the memory for recently heard songs, although it had no clear effect on the memory for the tutor song heard in development. In addition, in females, but not males, estradiol depletion disrupted the typical neural response bias for conspecific song. These results are consistent with evolving ideas about the dynamic effects of sex steroids on sensory brain function beyond the established role of these hormones in reproductive behavior. The observations further suggest how, in females in the sexually receptive state, estradiol production in addition to its production in the brain itself, may influence the way the songs of potential suitors are discriminated, remembered and compared in the brain, thus contributing to the process of mate selection.
NoteIncludes bibliographical references
Noteby Kathleen Marie Yoder
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.