Effects of duration on intensity discrimination: Psychophysical data and predictions from single‐cell response

An ROC analysis was performed on responses of single auditory‐nerve fibers (goldfish) and cochlear nucleus cells (gerbil) in order to predict intensity discrimination (in the goldfish and human) as a function of signal duration. To evaluate that the mean and variability of spike counts within single units account for psychophysical performance, spike number distributions were obtained (N = 100) for several durations (20 to 400 ms) and level differences (0.5–4 dB) at a unit's best frequency. The percent correct performance based on spike counts was found by generating ROC curves from empirical distributions and computing the area under the ROC [P(A)]. Theoretical psychometric functions were compared with psychometric functions from human and goldfish listeners obtained using a 21FC paradigm (human) and a rating method in classical respiratory conditioning (goldfish). The forms of the neural and psychophysical duration functions are similar in the mammal and the fish, but the fish shows higher thresholds co...