Frequency and Temporal Processing in the Auditory System of Anurans

Abstract

Let us begin by considering a basic problem in species-specific animal sound communication. In order to achieve a meaningful transfer of information, the sender and the receiver must agree on the set of messages that they will use, as well as the rules governing their interpretation. This mutual agreement arises innately or else through learning. In the case of terrestrial animals, the sender and the receiver are linked over a distance by a communication channel consisting of an airborne pathway and any intervening vegetation. The desired message which passes through this channel is embodied in the physical properties within the sender’s signal. But, in general, the communication channel is contaminated by extraneous signals from other sources which are of little or no interest to the sender and receiver. This contamination can be considered as additive background noise which interferes with the receiver’s detection of the sender’s signal (Fig. 1). This therefore raises a fundamental question: What operations should the receiver perform in order to optimize detection of the sender’s signal?