Basilar membrane

The basilar membrane within the cochlea of the inner ear is the part of the auditory system that decomposes incoming auditory signals into their frequency components. This allows higher neural processing of sound information to focus on the frequency spectrum of input, rather than just the time domain waveform. In brief, the membrane is tapered and is stiffer at one end than the other. This causes sound input of a certain frequency to preferentilly vibrate a particular location of the membrane due to the physical property of resonance. High sounds will lead to vibrations at one end of the membrane, low sounds at the other. The localized vibration of the basilar membrane is then transduced into neural signals by the inner hair cells of the Organ of Corti, which sits on top of the basilar membrane. The hair cells above the most resonating segment of the membrane will fire the most signals, thus the neural code leaving the ear through the auditory nerve is frequency coded.