Recovery of the compound action potential following prior stimulation: Evidence for a slow component that reflects recovery of low spontaneous-rate auditory neurons

Relkin and Doucet (1991) have shown that recovery of single auditory-nerve neurons from the effects of prior stimulation by a 100 ms pure tone varies with the spontaneous activity of the neuron. Recovery of thresholds for low spontaneous-rate (SR) neurons takes up to 2.0 s, a factor of 10 times greater than the 200 ms required for recovery of high SR neurons. The purpose of this study was to see if the different recovery rates for the two classes of neurons is reflected in recovery of the amplitude of the compound action potential (CAP) recorded in response to a brief probe tone with similar prior stimulation. We present evidence for two components in the recovery of the CAP amplitude, a slow and fast component, that have time courses similar to those for the recovery of responses for single low and high SR neurons, respectively. Thus, we conclude that the recovery of the CAP amplitude does indeed reflect the underlying recovery processes of single auditory-nerve neurons.