Auditory stream segregation using bandpass noises: evidence from event-related potentials

Abstract

The current study measured neural responses to investigate auditory stream segregation of noise stimuli with or without clear spectral contrast. Sequences of alternating A and B noise bursts were presented to elicit stream segregation in normal-hearing listeners. The successive B bursts in each sequence maintained an equal amount of temporal separation with manipulations introduced on the last stimulus. The last B burst was either delayed for 50% of the sequences or not delayed for the other 50%. The A bursts were jittered in between every two adjacent B bursts. To study the effects of spectral separation on streaming, the A and B bursts were further manipulated by using either bandpass-filtered noises widely spaced in center frequency or broadband noises. Event-related potentials (ERPs) to the last B bursts were analyzed to compare the neural responses to the delay vs. no-delay trials in both passive and attentive listening conditions. In the passive listening condition, a trend for a possible late mismatch negativity (MMN) or late discriminative negativity (LDN) response was observed only when the A and B bursts were spectrally separate, suggesting that spectral separation in the A and B burst sequences could be conducive to stream segregation at the pre-attentive level. In the attentive condition, a P300 response was consistently elicited regardless of whether there was spectral separation between the A and B bursts, indicating the facilitative role of voluntary attention in stream segregation. The results suggest that reliable ERP measures can be used as indirect indicators for auditory stream segregation in conditions of weak spectral contrast. These findings have important implications for cochlear implant (CI) studies—as spectral information available through a CI device or simulation is substantially degraded, it may require more attention to achieve stream segregation.

Detecting changes in dynamic and complex acoustic environments

“…The analysis was focused on a subset of the recording electrodes, namely an auditory (central location, El.1; corresponding to the center in Nie et al, 2014) and a centro-parietal (14,27,28; corresponding to Twomey et al, 2015) set. Depicted potentials show averages across each set of electrodes.…”

“…one in the equidistant layout of EasyCap, equal to Cz; corresponding to the center in Nie et al, 2014). The CPP signal was based on a set of centro-parietal electrodes (El.…”

Selective attentional processes in cochlear implant recipients: Measurements of the attentional filter

“…Other studies have shown that some, but not all, implant recipients, using their speech processors, can segregate auditory streams on the basis of electrode location and other stimulus parameters (Chatterjee et al, 2006, Cooper and Roberts, 2007, Cooper and Roberts, 2009, Harris and Kamke, 2014. In normal hearing subjects , comparisons of mismatch negativity and cognitive components of cortical potentials show that preattentive processes can provide a basis for discriminating between different auditory streams that differ in spectral content (Nie et al, 2014 ). These authors speculate that CI recipients, in whom spectral information may be degraded, might have to rely on more active attentional processes, assumed to be cortical.…”

Cortical processing of phonetic and emotional information in speech: A cross-modal priming study

“…This positive-going deflection is often discussed as a possible variant of the P300 component, reflecting updating working memory (Hajcak, Dunning & Foti, 2009; also see Donchin & Coles, 1988). The P300 is known to be a neurocognitive index of novelty detection and attentional capture, and its amplitude is strongly dependent on the stimulus context and task demands (Nie, Zhang, & Nelson, 2014). Because Zhang et al (2010) also observed an N400 component in their experiment, they propose that the LPP may in fact be a P300 component reflective of updating working memory.…”