Detection of substrate vibrations by salamanders: eighth cranial nerve activity

Publisher Website
Google Scholar
Abstract
Eighth cranial nerve activity was recorded from supine and prostrate juvenile and adult Notophthalmus viridescens while vibrations were applied to either the dorsal or ventral surfaces. Increases in activity were obtained over a vibration frequency range from 20 to 650 Hz. Responses were produced over a maximum amplitude range from 0.018 to 30 μm peak-to-peak displacement, but the range limits varied at different frequencies. Eighth cranial nerve activity increased with vibration amplitude above an apparent threshold. The threshold varied with stimulus frequency, being lowest between 150 and 350 Hz. Responses to a steady-slate vibration were partially adapting or nonadapting. At higher amplitudes of vibration multiunit responses tended to be dominated by nonadapting activity. Some, but not all, activity was synchronized with the stimulus wave form, either at the same or double the frequency of the stimulus. The important features of the responses to vibration were due to afferent rather than efferent activity. The results show that the salamander ear is capable of transmitting considerable information about substrate vibrations to the central nervous system.

This publication has 0 references indexed in Scilit: