Discrimination of Schroeder-phase complex stimuli: Physiological, behavioral, and modeling studies in the Mongolian gerbil

Schroeder-phase tone complexes have been studied psychophysically, behaviorally, and physiologically in several species. These stimuli are comprised of equal-amplitude harmonics, defined by fundamental frequency (F0), sign and slope (C) of the phase spectra, and number of harmonics. Perceptual differences between positive (C + ) and negative (C-) phase spectra (time-reversed versions of each other) challenge the power-spectrum model and must be explained by temporal cues, either fine structure or the low-frequency fluctuations of peripherally filtered stimuli. Here, physiological, behavioral, and modeling studies of discrimination of Schroeder complexes in Mongolian gerbil will be presented. Behavioral discrimination of complexes with different C values or signs decreased as F0 increased from 50 to 400 Hz. Here we investigate whether peripheral neural fine structure or changes in low-frequency fluctuations of rate underlie discrimination. Modeling results show that both synaptic adaptation and frequency-d...