title: Auditory efferent activation in CBA mice exceeds that of C57s for varying levels of noise.
abstract: The medial olivocochlear efferent (MOC) system enhances signals in noise and helps mediate auditory attention. Contralateral suppression (CS) of distortion product otoacoustic emissions (DPOAEs) has revealed age-related MOC declines. Here, differences in CS as a function of contralateral noise intensity (43-67 dB sound pressure level) were measured; 2f1-f2 DPOAE grams were recorded for young adult CBA and C57 mice. In CBAs, CS was a monotonic function of contralateral noise level. The C57s showed normal hearing, measured with DPOAE amplitudes and auditory brainstem response thresholds, but showed little CS, suggesting a loss of efferent dynamics preceding any deficiencies of the afferent auditory system.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Frisina
authors.forename: S R
authors.initials: SR
authors.lastname: Newman
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Zhu
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001307:Auditory Perception / Q000502:physiology*; D005246:Feedback / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009476:Neurons, Efferent / Q000502:physiology*; D009622:Noise; D013045:Species Specificity