Tuning curves of auditory-nerve fibers

Abstract

The tuning curves of single fibers in the auditory nerve of cats have a sharp, low-threshold portion (tip) and a broader, high-threshold portion (tail). The relationship of tip to tail changes as a function of characteristic frequency (CF). Fibers with high CF have tails extending to much lower frequencies. For units with CF around 1 kHz, the tip and tail merge to form a V-shaped curve. For units with lower CF, the tail can be seen on the high-frequency side of the tuning curve. The “seams” in the tuning curves that represent the merging of tip and tail occur at frequencies for which there is a change in slope of the phase versus frequency function. Under certain pathological conditions such as ototoxic poisoning or acoustic trauma, the tip and tail may be affected differently. The relationship of the tip and tail to discharge rate versus SPL functions will be discussed. [Work supported in part by NIH.]