Electrical stimulation of the eighth nerve in cat: Temporal properties of unit responses in the large spherical cell region of the AVCN

Single‐unit responses to intracochlear electrical stimulation were studied. Responses were highly phase‐locked to sinusoidal stimulation at frequencies less than 4 kHz. At any given stimulus frequency, synchronization indexes were greater than those that have been reported for eighth nerve responses to acoustic stimuli. At the onset of a low‐frequency (i.e., below 800 Hz) sinusoidal stimulus, firing rate gradually increased over many tens of milliseconds. Rise times were as long as 50–100 ms for low‐intensity, low‐frequency sinusoidal stimulus bursts. At greater intensities and/or higher stimulus frequencies, the response rise times were considerably shorter. Preliminary results indicate that responses to trains of short‐duration biphasic pulses do not exhibit such slow rise times. These results may relate to Eddington's [Ann. Otol. Rhinol. Laryngol. 87 (Suppl. 53), 1–37 (1978)] finding that behavioral threshold increases sharply as the burst duration of a sinusoidal stimulus is decreased. However, thresh...