Observations on Models of the Basilar Papilla of the Frog's Ear

Observations on models of the tectorial membrane in the basilar papilla of the frog are described. The model membranes constitute a series of increasing complexity, and are studied with sinusoidal stimulation and stroboscopic illumination. It is found that traveling waves occur on these models, and that frequency-dependent maxima are formed. By arrangements of fibers and small masses on the membranes the direction of wave travel and location of maxima can be altered. Measurements of the elastic gradients on the membranes show that waves tend to follow a path defined by the smallest change in elastic properties per unit distance. It is concluded that the frog's basilar papilla is capable of performing frequency analysis according to the place principle.