Alerting Signals and Detection in a Sensory Network

Abstract

Detection theories are based on the proposition that nature designs our sense organs to recover signals from external noise. Not much credence is given to the idea that an essential part of the noise arises internally in conveying information to the brain or that the detected event may be an alert signal rather than a literal copy of the stimulus. Transmission is portrayed here as a birth-and-death process. New events are created and existing events are lost as messages pass from the sense organ to a central decision-making area. Messages are either alert signals or actual "images" of the stimulus formed by branching chains. In both cases, a telltale multiplicative noise appears at the output. We develop: (1) a branching-chain transmission mechanism, (2) its output counting distribution, (3) characteristic properties of branching-chain noise, and (4) examples of the effects of such noise on the discriminability of pure-tone signals. © 1995 Academic Press, Inc.