Shift in the cochlear place-frequency map after noise damage in the mouse.
The cochlear place-frequency map, determined from noise-damaged mice, is shifted to lower frequencies by up to one octave compared with the map determined from normal hearing mice. To test the hypothesis that the shift results from damage to the cochlear amplifier, we measured frequency tuning curves from the same neurons before and after noise exposure. Noise damage resulted in loss of tuning and elevation of thresholds. The neuronal characteristic frequency shifted by 0.6-1.2 octaves, dependent on frequency. The shift in characteristic frequency was used to calculate a shifted place-frequency map. We conclude that desensitization of areas in the inner ear after noise exposure can explain the shift of the map after noise damage relative to the normal physiological map.
Müller
Marcus
M
Physiology II, J.W. Goethe-University, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany. m.mueller@em.uni-frankfurt.de
Smolders
Jean W T
JW
D000161:Acoustic Stimulation / Q000379:methods; D000200:Action Potentials / Q000528:radiation effects; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology* / Q000528:radiation effects; D003051:Cochlea / Q000473:pathology* / Q000503:physiopathology; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006317:Hearing Loss, Noise-Induced / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D009474:Neurons / Q000502:physiology* / Q000528:radiation effects; D009622:Noise / Q000009:adverse effects*