RECOVERY CHARACTERISTICS OF AUDITORY-NERVE FIBERS IN THE NORMAL AND NOISE-DAMAGED GUINEA-PIG COCHLEA

Spontaneous activity was analysed in auditory-nerve fibres innervating normal and noise-damaged cochleas. Spike occurrences were conceived a s point processes. Joint interval distributions and serial correlation coefficients reveal a weak history effect for succeeding intervals. T he point process is regarded as a renewal and the recovery function, b eing proportional to the hazard function, is determined from the inter val probability density function. In 29 out of 60 fibres the latter sh ows peculiarities which result in a deviation from a monotonically inc reasing recovery function. For three fibres of low characteristic freq uency the interval probability function shows an oscillatory pattern a nd for 26 fibres this function exhibits an early, sharp peak around 1. 1 ms irrespective of characteristic frequency, spontaneous rate, or co chlear damage. The recovery function is not different between fibres w ith normal and those with abnormally high thresholds and exhibits an e xponential recovery with one time constant of average value 1.6 ms. Bu rsting activity is found in only one fibre from the abnormally high th reshold group.