PROPOSED EXPLANATION OF SYNCHRONY OF AUDITORY-NERVE IMPULSES TO COMBINATION TONES

When the acoustic stimulus consists of two sinusoidal components (frequencies f1 and f2), the impulses of a single auditory nerve fiber can show partial synchrony with either of these components (provided the frequencies stay below approx 5 kHz). Often a synchrony with an externally generated combination tone of frequency 2f1âf2 can be detected as well. It is shown in this letter than such a behavior is a logical consequence of the assumption that nerve impulses are elicited at the peaks of the stimulus waveform. In addition, it is demonstrated that only special combination tones will show this phenomenon. Many of the experimental results on this type of synchrony can be explained in this way. It is thus not necessary to assume that a special physiological mechanism is responsible for the observed synchrony per se. But deviations from the basic properties derived here should be observed closely, because these do give useful indications about cochlear physiology. © 1969, Acoustical Society of America. All rights reserved.