Critical bands following the selective destruction of cochlear inner and outer hair cells

Critical bandwidths and absolute intensity thresholds were measured in cats before and after kanamycin treatment which induced selective inner and outer hair cell losses. Hair cell losses were measured from cochleograms constructed from surface preparations of the organ of Corti. Results suggested that, for the test frequencies and stimulus intensities employed, critical bandwidths were not affected for frequencies tonotopically located in cochlear regions where only outer hair cells were lost. Critical bands were widened or not measurable only when inner hair cell losses exceeding 40% were also associated with complete loss of outer hair cells. The experiment suggests that cochlear frequency selectivity can be mediated by inner hair cells alone.