Cochlear neurons: Frequency selectivity altered by perilymph removal

Removal of perilymph from the scala tympani of the guinea pig cochlea reversibly broadened the tuning curves of single spiral ganglioll cells emanating from the basilar membrane. Thus, fluid continuity along the membrane is essential for normal cochlear function, in particular for sharp neural tuning curves. These data reveal a possible source of error in some estimates of basilar membrane motion and suggest a reappraisal of current concepts of the mechanism of sharp tuning in primary auditory nerve fibers.