The Journal of Neuroscience, September 1, 2002, 22(17):7774-7787
Vocal Memory and Learning in Adult Bengalese Finches with
Regenerated Hair Cells
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
Critical learning periods are common in vertebrate development. In
many birds, song learning is limited by a critical period; juveniles
copy songs from adult birds by forming memories of those songs during a
restricted developmental period and then using auditory feedback to
practice their own vocalizations. Adult songs are stable over time
regardless of exposure to other birds, but auditory feedback is
required for the maintenance of stable adult song. A technique was
developed to reversibly deafen Bengalese Finches by destruction and
regeneration of inner ear auditory hair cells. With this approach, we
asked two questions about the plasticity of song information stored in
the adult brain. First, do adult birds store memories or
"templates" of their songs that exist independent of auditory
reinforcement? Such memories could be used to control vocal output by
acting as fixed models of song to which ongoing vocalizations are
matched. Second, can adult song learning, which does not normally occur
in this species, be induced by removing and then restoring hearing?
Studying changes in adult song behavior during hair cell loss and
regeneration revealed two findings: (1) adult birds store memories or
templates of their songs that exist independent of auditory input and
can be used to restore normal vocal behavior when hearing is restored; (2) under experimental circumstances, adult birds can be induced to
acquire song material from other birds. Results suggest that, in
Bengalese Finches, the degree of behavioral and neural plasticity in
juvenile and adult birds may be less distinct that previously thought.
Key words:
songbird; song; plasticity; auditory feedback; hair cell; vocalization
Copyright © 2002 Society for Neuroscience 0270-6474/02/22177774-14$05.00/0
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