Travelling wave motion along the pigeon basilar membrane.

The basilar membrane (BM) motion in the pigeon was measured using the Mössbauer technique. Tonotopic frequency mapping and travelling wave motion were observed over the basal 35% of the BM. The sensitivity and sharpness of the BM tuning depended on the physiological condition of the cochlea. The observed amplitude responses did not match the frequency threshold tuning curves of single primary auditory fibers.