The Change of Discharge Frequency by A.C. Stimulus in a Weak Electric Fish

Abstract

1. A South American gymnotid Eigenmannia, changes the discharge frequency of its electric organ when a weak electric signal is applied to it with a frequency very close to that of its own discharge. Otherwise, the discharge frequency is extremely constant at a fixed temperature. 2. When the frequency of the applied signal is higher or lower than that of the fish discharge, the response is a decrease or increase of the discharge frequency, respectively. When the two frequencies are exactly the same, the response fails to occur. 3. The threshold of this response is very low. In one fish it was about 3 µ V./cm.