Abstract: Stochastic resonance phenomenon in the biological sensory systems has been studied through the signal detection theories and the psychophysical experiments. In this paper, sensory systems are considered as a threshold detector including the receiver part and the classifier part. Compared with conventional models regarding the receiver part of sensory system as a linear or single non-linear system, a summing network was constructed by MacCulloch-Pitts neurons to simulate the receiver part. The simulation results show that the relevant index of the detectability of signal exhibit the stochastic resonance behaviours. The psychophysical experiments were carried out through the 2IFC (two interval two alter native forced choice) method. The experimental results qualitatively verify the conclusion in accordance with the theoretical model. These works give a proof that stochastic resonance is not only epiphenonmenon in sensory systems.

Key words: signal detection theory , stochastic resonance, psychophysical experiment, MacCulloch-Pitts neuron