The Journal of Neuroscience, January 1, 1999, 19(1):358-371
High-Frequency Auditory Feedback Is Not Required for Adult Song
Maintenance in Bengalese Finches
Sarah M. N.
Woolley and
Edwin W
Rubel
Virginia Merrill Bloedel Hearing Research Center, Departments of
Otolaryngology-Head and Neck Surgery and Physiology and Biophysics,
University of Washington, Seattle, Washington 98195
Male Bengalese finches do not normally change their vocal patterns
in adulthood; song is stereotyped and stable over time. Adult song
maintenance requires auditory feedback. If adults are deafened, song
will degrade within 1 week. We tested whether feedback of all sound
frequencies is required for song maintenance. The avian basilar papilla
is tonotopically organized; hair cells in the basal region encode high
frequencies, and low frequencies are encoded in progressively apical
regions. We restricted the spectral range of feedback available to a
bird by killing either auditory hair cells encoding higher frequencies
or those encoding both high and low frequencies and documented
resultant changes in song. Birds were treated with either Amikacin
alone to kill high-frequency hair cells or Amikacin and sound exposure
to target hair cells across the entire papilla. During treatment, song
was recorded from all birds weekly. After treatment and song recording, evoked-potential audiograms were evaluated on each bird, and papillas were evaluated by scanning electron microscopy. Results showed that
hair cell damage over 46-63% of the basal papilla and the corresponding high-frequency hearing loss had no effect on song structure. In birds with hair cell damage extending further into the
apical region of the papilla and corresponding low-frequency and
high-frequency hearing loss, song degradation occurred within 1 week of
beginning treatment and was comparable with degradation after surgical
deafening. We conclude that either low-frequency spectral cues or
temporal cues via feedback of the song amplitude envelope are
sufficient for song maintenance in adult Bengalese finches.
Key words:
song; auditory feedback; hair cell; sound frequencies; finch; hearing; auditory; deprivation
Copyright © 1999 Society for Neuroscience 0270-6474/99/191358-14$05.00/0
Previous Article | Next Article
