Abstract
Lateralization of complex high-frequency sounds is conveyed by interaural level differences (ILDs) and interaural time differences (ITDs) in the envelope. In this work, the authors constructed an auditory model and simulate data from three previous behavioral studies obtained with, in total, over 1000 different amplitude-modulated stimuli. The authors combine a well-established auditory periphery model with a functional count-comparison model for binaural excitatory-inhibitory (EI) interaction. After parameter optimization of the EI-model stage, the hemispheric rate-difference between pairs of EI-model neurons relates linearly with the extent of laterality in human listeners. If a certain ILD and a certain envelope ITD each cause a similar extent of laterality, they also produce a similar rate difference in the same model neurons. After parameter optimization, the model accounts for 95.7% of the variance in the largest dataset, in which amplitude modulation depth, rate of modulation, modulation exponent, ILD, and envelope ITD were varied. The model also accounts for 83% of the variances in each of the other two datasets using the same EI model parameters.
Highlights
Accurate sound localization requires precise neural mechanisms for processing relevant binaural cues, such as interaural time difference (ITD, here denoted by Dt) and interaural level difference (ILD)
The primary goal of the current study is to investigate whether a model framework that employs neither a delayline scheme nor a multiplication-based cross-correlation can still account for the psychoacoustic data of Bernstein and Trahiotis (2003, 2012) and of Dietz et al (2015)
The present study demonstrated that the lateralization of complex, high-frequency stimuli can be simulated with a relatively simplistic model deduced from mammalian auditory brainstem physiology and a linear hemispheric ratedifference decoder
Summary
Accurate sound localization requires precise neural mechanisms for processing relevant binaural cues, such as interaural time difference (ITD, here denoted by Dt) and interaural level difference (ILD). A fundamental question in the study of binaural-information processing is how to relate the neuronal representations of these cues to the evoked percepts. Binaural perception has most often been modeled and explained by interaural cross-correlation. Such a coincidencedetecting model unit responds maximally when the relative internal delay between its bilateral inputs compensates for the external ITD (e.g., Jeffress, 1948; Lindemann, 1986; Bernstein and Trahiotis, 2003; Stern and Shear, 1996; Colburn, 1977). A delay-line mechanism may not be operational in the mammalian binaural pathway (e.g., Grothe et al, 2010), but the issue is still under debate (Leibold and Grothe, 2015; Yin et al, 2019; Joris and van der Heijden, 2019)
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