On the Occurrence of Phase-locked Pulse Train in the Peripheral Auditory System

Abstract

The missing fundamental is not in the frequency band of one channel of a telephone line (from 300Hz to 3400Hz), but we can perceived it over the telephone. It is considered that the missing fundamental f0 is produced in the auditory center, when we listen to a complex tone of f1=nf0 and f2=(n+k)f0. f0 is known as the missing fundamental. Some phenomena, which were made clear by psycho-acoustic experiments, have no evidence data of electrophysiology. The missing fundamental phenomenon is one of the phenomena. By making physiological models we are trying to make clear the mechanism how the missing fundamental is produced. We already showed how the information of the missing fundamental f0 explicitly appeared on the aggregated autocorrelogram of the output pulse train for input signal f1 to one cochlear model and the output pulse train for input signal f2 to another cochlear model. We have made clear that the models have the following characteristics about the models of two neurons (Primary Auditory Nerve (Integrate-and-Fire unit with spontaneous discharge) and Anteroventral Cochlear Nucleus (agreement detector)) that play an important role in producing the information of the missing fundamental. The model of Primary Auditory Nerve generates the pulse train (quasi periodic pulse train) adding spontaneous discharge to periodic pulses for input periodic signal. The model of Anteroventral Cochlear Nucleus works as agreement detector of pulses of the input pulse trains (above-mentioned quasi periodic pulse trains (21 quasi periodic pulse trains in Fig.1)) and generates a periodic pulse train (a phase-locked pulse train) which synchronizes an periodic signal to an cochlear model.The afferent nerves from right Cochlear Nucleus and left Cochlear Nucleus is aggregated at Superior Olivary Complex. We suppose that each periodic pulse train from each ear is fed to Superior Olivary Complex.