Some poststimulatory effects on the whole nerve action potential

Short-term poststimulatory effects on the N1 component of the auditory-nerve compound action potential (CAP) were investigated in Mongolian gerbils. Some effects of conditioner level, conditioner frequency and probe level were assessed. In most cases, poststimulatory decrements occurred. The decrements were independent of probe intensity when the conditioner was close in frequency and of equal or less intensity than the probe. At some other conditioner frequencies, decrements decreased as probe intensity increased. Departures from these relationships occurred when a more intense conditioner was applied. In some instances, increases in CAP amplitude were also observed. The roles of single unit responses including spread of cochlear excitation, and possible mechanisms for poststimulatory facilitation are discussed.