Jerzy E. Rose

Temporal Position of Discharges in Single Auditory Nerve Fibers within the Cycle of a Sine‐Wave Stimulus: Frequency and Intensity Effects

Period histograms, which display the distribution of spikes throughout the period of a periodic stimulus, were computed for discharges recorded from single auditory nerve fibers of the squirrel monkey when low‐frequency tones were employed. For frequencies up to about 4 kHz, where phase locking is observed, the average phase angle of the discharges was tracked as frequency was varied in small steps from low to high. To a first approximation, the cumulative shift in average phase angle is a linear function of frequency as would be observed for an ideal delay line. The slopes of these phase‐versus‐frequency lines were found to be related through a power law to the best frequencies of the fibers. Thus, it seems possible to estimate the travel time of a mechanical disturbance between the oval window and any point on the cochlear partition. A more detailed examination revealed that average phase angle is also sensitive to intensity, depending upon the relation of the stimulating frequency to the best frequency...

Responses of Single Fibers in the Auditory Nerve of the Squirrel Monkey to Paired Phase‐Locked Low‐Frequency Tones

Data were analyzed on‐line and from analog tape using a LINC computer. Stimuli were 10‐sec complex sounds generated by summing two phase‐locked low‐frequency sinusoids. Both frequencies were within the response area of the unit and were related in ratios of small integers. Periodograms, i.e., distributions of unit responses over one period of the complex waveform summed for all repetitions of the waveform stimulus, were studied. The findings suggest that units discharge preferentially at times when the displacements in one direction of the cochlear partition are at or near maximal values. When intensity or phase of either stimulus component is varied with a resulting change in the complex waveform, there is a corresponding change in the periodogram. Concurrently, interspike intervals are grouped around values which are integral multiples of the time between the peaks of the periodogram, and the frequency of occurrence of such intervals is a function of the amplitude of these peaks (NB‐06225).

Temporal Position of Discharges in Single Auditory Nerve Fibers within the Cycle of a Sine‐Wave Stimulus

Period histograms, which display the distribution of spikes throughout the cycle of the sinusoidal stimulus, were computed for discharges recorded from single auditory nerve fibers of the squirrel monkey when low‐frequency tones were employed. For each histogram, an average phase angle was determined, which constitutes a measure of central tendency for the spike distribution. For frequencies up to 4 kHz, where phase locking is observed, the average phase angle was tracked as frequency was varied in small steps from low to high. To the first approximation, the cumulative shift in average phase angle is a linear function of frequency, as would be anticipated for a constant‐propagation delay. A more detailed examination revealed that average phase angle is also sensitive to intensity, depending upon the relation of the stimulating frequency to the best frequency. For stimulating frequencies below best frequency, discharges tend to occur progressively later in the cycle as intensity increases. Above best freq...