Transduction of natural stimuli and noise in rod photoreceptors of the tiger salamander, Ambystoma tigrinum

Signal, noise and response properties of salamander rod photoreceptors were studied by measuring: (a) the circulating current of rods which were adapted to darkness and to a wide range of backgrounds; (b) the contrasts of natural environments; (c) the effect of adaptation on the linear response range of rods; and (d) the behavior of rods responding to dynamically-modulated stimuli having the range of contrasts found in nature. In the dark, the circulating current contained two noise components analogous to those described in toad. A discrete noise component consisted of events occurring at a rate of 1 event per 32 sec (21...