Growth of masker level with signal level as a function of preceding stimulation

Abstract

Some recent data suggest that stimulating the auditory system with sound may turn down active processing. The basic paradigm used to show this is to measure the level of a notched-noise, long-duration masker required to just mask a short-duration tone that occurs near masker onset. The preceding stimulation has been a precursor that was either a fixed-level broadband noise [Strickland, J. Acoust. Soc. Am. (in press)], or an extension of the notched-noise masker, which varied in level [Strickland, J. Acoust. Soc. Am. 107, 2915 (2000)]. The present experiment was done to examine the effects of a notched-noise precursor that had the same frequency characteristics as the masker, but which would be fixed in level. The signal was a 10-ms, 4-kHz tone. The notched-noise masker was 200 ms, and the precursor was 205 ms. For a given precursor level, the growth of masker level with signal level was determined. This data was used to calculate the effective input–output functions of the signal and the masker. These functions will be compared to those published physiological measures from the chinchilla cochlea. [Work supported by NIH (NIDCD).]