Effects of tonotopicity, adaptation, modulation tuning, and temporal coherence in “primitive” auditory stream segregation

Abstract

The perceptual organization of two-tone sequences into auditory streams was investigated using a modeling framework consisting of an auditory pre-processing front end [Dau et al., J. Acoust. Soc. Am. 102, 2892-2905 (1997)] combined with a temporal coherence-analysis back end [Elhilali et al., Neuron 61, 317-329 (2009)]. Two experimental paradigms were considered: (i) Stream segregation as a function of tone repetition time (TRT) and frequency separation (Δf) and (ii) grouping of distant spectral components based on onset/offset synchrony. The simulated and experimental results of the present study supported the hypothesis that forward masking enhances the ability to perceptually segregate spectrally close tone sequences. Furthermore, the modeling suggested that effects of neural adaptation and processing though modulation-frequency selective filters may enhance the sensitivity to onset asynchrony of spectral components, facilitating the listeners' ability to segregate temporally overlapping sounds into separate auditory objects. Overall, the modeling framework may be useful to study the contributions of bottom-up auditory features on "primitive" grouping, also in more complex acoustic scenarios than those considered here.

Assessing the effects of temporal coherence on auditory stream formation through comodulation masking release

“…Previous studies have shown that onset/offset asynchronies larger than 20-40 ms lead to increased stream segregation (e.g., Turgeon et al, 2002;Turgeon et al, 2005;Bregman and Pinker, 1978;Micheyl et al, 2013b;Christiansen et al, 2014), in good agreement with the data from this study.…”

Computational speech segregation based on an auditory-inspired modulation analysis

“…As demonstrated by Ewert and Dau (2000), the processing of envelope fluctuations can be described effectively by a second-order bandpass filterbank with logarithmically scaled modulation filters. Such a processing has recently also been successful in speech intelligibility prediction studies (Jørgensen and Dau, 2011;Jørgensen et al, 2013), computational scene analysis (Christiansen et al, 2014), and sound textures synthesis (McDermott and Simoncelli, 2011). Similar processing based on auditory coding principles might also be advantageous in computational speech segregation, but this has not yet been examined.…”

Temporal coherence structure rapidly shapes neuronal interactions

“…Temporal coherence also explained why a few synchronous tone sequences perceptually pop-out even in the midst of a dense background of random tones4, and why prominent electroencephalogram responses to these synchronous tones emerge even in the absence of other distinguishing features such as global changes in signal power or local tone densities56. Finally, temporal coherence has also been demonstrated to play a role in co-modulation masking release78 and its dynamics have recently been imaged in the primary auditory cortex9.…”