When and how envelope "rate-limitations" affect processing of interaural temporal disparities conveyed by high-frequency stimuli.

The purpose of this chapter is to bring together historical and current findings that reveal the presence, influence, and operation of a type of envelope “rate-limitation.” The rate-limitation has been revealed in both monaural and binaural experiments. Specifically, there appears to be a low-pass envelope-filtering process that (1) functionally attenuates fluctuations of the envelope above about 150 Hz and (2) is not attributable to peripheral band-pass filtering. We show a variety of empirical outcomes and theoretical analyses that converge to demonstrate and to describe how this type of filtering constrains the processing of interaural temporal disparities (ITDs) conveyed by the envelopes of high-frequency stimuli in experiments concerning binaural detection. Included are recent behavioral and neurophysiological findings regarding how such filtering may vary with the center frequency of the stimulus.