Michael J. Hewitt
Dept. of Human Sci., Univ. of Technol., Loughborough LE11 3TU, UK
A low pitch sensation can be heard when a mid-frequency (e.g., 500--4000 Hz) carrier is amplitude modulated at a rate between 100 and 400 Hz. The output of multipolar neurons in the ventral cochlear nucleus are known to reflect strongly modulation of the acoustic stimulus and even to amplify it. Other cells in the inferior colliculus respond by increasing their rate of firing when a rate of amplitude modulation, critical to that cell, is applied to a stimulating tone. The system to be described consists of a model of the auditory periphery that simulates auditory-nerve fiber input, arrays of multipolar point-neuron models that receive this input, and arrays of inferior colliculus unit models that receive input from the multipolar cells. Individual model units behave similarly to physiological units. Arrays of IC model units also show many properties associated with psychophysical studies of pitch including the ability to extract ambiguous pitch from inharmonic tone complexes.