ABSTRACT
Below 200 Hz, no particular region of the basilar membrane cells appears to respond best. Since the pitch is determined by the rate of firing, the loudness of low frequency sounds is probably determined by the number of cells firing. It is possible that some form of rate coding also takes place for frequencies above 200 Hz, but this is likely to serve only as a secondary mechanism. If a person is deaf because of the loss of basilar membrane stimulation, a cochlear implant device can be implanted that mechanically converts the sound waves into vibrations at different regions of the membrane according to the frequency. When a high frequency sound is heard, the thinner base of the basilar membrane vibrates maximally. As the sound lowers in frequency, the maximal vibration moves towards the thicker apex of the membrane.
