Auditory phase opponency: A temporal model for masked detection at low frequencies

We present a model for tone-in-noise detection at low frequencies that includes a physiologically realistic mechanism for processing the information in neural discharge times. The proposed model exploits the frequency-dependent phase properties of the tuned filters in the auditory periphery and uses cross-auditory-nerve-fiber coincidence detection to extract temporal cues. Information in the responses of model coincidence detectors is quantified and compared to human performance in a masked detection task. The response of some cross-frequency coincidence detectors are reduced when a low-frequency tone is added to a noise because of phase differences between fibers tuned to different frequencies. We refer to this response reduction as "phase opponency." For super-critical masker bandwidths, the PO model succeeds in predicting detection of low-frequency tones in roving-level maskers, a psychophysical task for which the classical energy model fails. The PO model describes a physiologically realistic mechanism for extracting spatio-temporal information that can be applied to other sensory systems in which spatially overlapping and partially correlated temporal information is important.