title: Electrophysiological study of the maturation of auditory responses from the inner ear of the chick.
abstract: Three electrophysiological functions of the chick basilar papilla were studied during development by recording the compound actin potential (AP) at the round window. The auditory thresholds showed a continuous maturation between the fifteenth day of incubation (E15) and the first post-hatching day (P1), when they attained adult values. Responses matured first to low frequencies and later to high frequency stimuli. The input-output (intensity-amplitude) functions matured regularly and never demonstrated the classical two slopes seen in mammals. The tuning properties, studied by tone-on-tone masking of the AP, achieved mature values before the thresholds; the Q10s reached adult values at E17 for a 500-Hz probe tone and at E19 for a 1000-Hz probe tone. The fact that a low-to-high frequency development trend was found with the embryonic middle ear cleared of fluids further suggests that this property of auditory ontogeny may be a function of changes in the transduction properties of the cochlea.
mesh_terms: D000375:Aging; D000818:Animals; D001307:Auditory Perception / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology; D002642:Chick Embryo; D002645:Chickens; D003051:Cochlea / Q000294:innervation*; D003055:Cochlear Microphonic Potentials; D003056:Cochlear Nerve / Q000502:physiology*; D010898:Pitch Perception / Q000502:physiology; D012405:Round Window, Ear / Q000294:innervation*