Physiological mechanisms of masking and intensity discrimination
Bertrand Delgutte · The Journal of the Acoustical Society of America · 1989
Recent electrophysiological studies in which stimulus paradigms were designed to mimic those of psychophysics suggest that a broad range of psychophysical data on masking and intensity discrimination can be simply explained by assuming that signal detection is primarily based on average discharge rate informal ion in auditory-nerve fibers, provided that information from high-threshold fibers is taken into account. These studies further suggest that tone-on-tone masking is due both to spread of the excitation produced by the masker to the signal place along the cochlea, and to suppression of the signal by the masker, with the relative importance of the two mechanisms depending on masker level and frequency separation between signal and masket. In particular, two-tone rate suppression is largely responsible for the upward spread of masking at high masker levels and for differences between simultaneous and nonsimultaneous masking techniques. New results will also be presented on unmasking due to suppression of the masker by the signal, improvements in signal detectability by off-frequency listening, and the role of olivocochlear efferents in signal detection. [Work supported by NIH Grant NS13126.]