Slow NMDA-EPSCs at synapses critical for song development are not required for song learning in zebra finches.
Birdsong, like human speech, is learned via auditory experience during a developmentally restricted sensitive period. Within projection neurons of two avian forebrain nuclei, NMDA receptor-mediated EPSCs (NMDA-EPSCs) become fast during song development, a transition posited to limit learning. To discover whether slow NMDA-EPSCs at these synapses are required for learning, we delayed song learning beyond its normal endpoint, post-hatch day (PHD) 65, by raising zebra finches in isolation from song tutors. At PHD45, before learning, isolation delayed NMDA-EPSC maturation, but only transiently. By PHD65, NMDA-EPSCs in isolates were fast and adult-like, yet isolates presented with tutors readily learned song. Thus song learning did not require slow NMDA-EPSCs at synapses critical for song development.
Livingston
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FS
Department of Neurobiology, Duke University Medical Center,Box 3209, Durham, North Carolina 27710, USA.
White
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SA
Mooney
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R
D000161:Acoustic Stimulation; D000375:Aging; D000818:Animals; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology*; D006317:Hearing Loss, Noise-Induced / Q000503:physiopathology; D066298:In Vitro Techniques; D007700:Kinetics; D007858:Learning / Q000502:physiology*; D008297:Male; D016202:N-Methylaspartate / Q000378:metabolism*; D016548:Prosencephalon / Q000166:cytology / Q000254:growth & development / Q000502:physiology; D012934:Social Isolation; D020308:Songbirds / Q000254:growth & development / Q000502:physiology*; D013569:Synapses / Q000378:metabolism*; D013739:Testosterone / Q000097:blood; D013997:Time Factors; D014828:Vocalization, Animal / Q000502:physiology*
D013739:Testosterone; D016202:N-Methylaspartate