Electrical stimulation of the auditory nerve. III. Response initiation sites and temporal fine structure.

摘要: Abstract Latency, temporal dispersion and input-output characteristics of auditory nerve fiber responses to electrical pulse trains in normal chronically deafened cat ears were classified tentatively associated with sites where activity is initiated. Spikes occurred one or more four discrete time ranges whose endpoints overlapped partially. A had latencies B 1 2 (0.45–0.9 ms, 25–40 μs, 1.9 dB) likely stemmed from at myelinated unmyelinated peripheral processes, respectively. C (0.9–1.2 >100 μs) originated direct stimulation inner hair cells, D (>1.1 >8 arose propagating traveling waves possibly caused by electrically induced motion outer cells. recorded only acoustically responsive ears. Mean spikes all usually decreased intensity, two even three was often observed the same spike train. Latency shifts range another as intensity increased. Some could be attributed opposite-polarity phase biphasic pulse. In these cases, dynamic approximately equal for each latency. second type latency shift also observed, which exhibited dissimilar range. This behavior a centralward initiation site it monophasic well signals. Several fibers dual 40–90 μs difference between response peaks. may have nodes on either side cell body. Increasing stimulus rate 800–1000 pps produced small increases proportionate asymptotic discharge range, but thresholds did not improve slopes rate-intensity functions (in spikes/s/dB) change. Responses high-rate stimuli when rates exceeded 300–400 spikes/s. Spike cases depended strongly history. Implications speech processing strategies are discussed.