Article

Effects of Attention on Neuroelectric Correlates of Auditory Stream Segregation

University of Toronto, Toronto, Ontario, Canada
Journal of Cognitive Neuroscience (Impact Factor: 4.09). 02/2006; 18(1):1-13. DOI: 10.1162/089892906775250021
Source: PubMed

ABSTRACT

A general assumption underlying auditory scene analysis is that the initial grouping of acoustic elements is independent of attention. The effects of attention on auditory stream segregation were investigated by recording event-related potentials (ERPs) while participants either attended to sound stimuli and indicated whether they heard one or two streams or watched a muted movie. The stimuli were pure-tone ABA--patterns that repeated for 10.8 sec with a stimulus onset asynchrony between A and B tones of 100 msec in which the A tone was fixed at 500 Hz, the B tone could be 500, 625, 750, or 1000 Hz, and--was a silence. In both listening conditions, an enhancement of the auditory-evoked response (P1-N1-P2 and N1c) to the B tone varied with Deltaf and correlated with perception of streaming. The ERP from 150 to 250 msec after the beginning of the repeating ABA- patterns became more positive during the course of the trial and was diminished when participants ignored the tones, consistent with behavioral studies indicating that streaming takes several seconds to build up. The N1c enhancement and the buildup over time were larger at right than left temporal electrodes, suggesting a right-hemisphere dominance for stream segregation. Sources in Heschl's gyrus accounted for the ERP modulations related to Deltaf-based segregation and buildup. These findings provide evidence for two cortical mechanisms of streaming: automatic segregation of sounds and attention-dependent buildup process that integrates successive tones within streams over several seconds.

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Available from: Terence W Picton, Apr 15, 2015
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    • "The present study goes further, showing that deviant detection was significantly worse when listeners reported hearing a segregated percept, independent of frequency separation, the position of the deviant in the sequence and any dual-task interference effects. Although subjective reports and neural measures of streaming have often been collected simultaneously (Cusack, 2005; Dykstra et al., 2011; Gutschalk et al., 2005; Hill et al., 2012; Snyder et al., 2006; Szalárdy, Bõhm, et al., 2013; Szalárdy, Winkler, et al., 2013), to our knowledge, only one previous study has directly linked an objective behavioral measure of streaming with concurrent percept reports. Participants in Billig et al. (2013) heard sequences of repeated syllables that could be perceived as integrated or segregated due to spectral differences between the initial /s/ sound and the remainder (such as " stone " vs. " s " " dohne " ). "
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    ABSTRACT: Two experiments used subjective and objective measures to study the automaticity and primacy of auditory streaming. Listeners heard sequences of "ABA-" triplets, where "A" and "B" were tones of different frequencies and "-" was a silent gap. Segregation was more frequently reported, and rhythmically deviant triplets less well detected, for a greater between-tone frequency separation and later in the sequence. In Experiment 1, performing a competing auditory task for the first part of the sequence led to a reduction in subsequent streaming compared to when the tones were attended throughout. This is consistent with focused attention promoting streaming, and/or with attention switches resetting it. However, the proportion of segregated reports increased more rapidly following a switch than at the start of a sequence, indicating that some streaming occurred automatically. Modeling ruled out a simple "covert attention" account of this finding. Experiment 2 required listeners to perform subjective and objective tasks concurrently. It revealed superior performance during integrated compared to segregated reports, beyond that explained by the codependence of the two measures on stimulus parameters. We argue that listeners have limited access to low-level stimulus representations once perceptual organization has occurred, and that subjective and objective streaming measures partly index the same processes. (PsycINFO Database Record
    Full-text · Article · Sep 2015 · Journal of Experimental Psychology Human Perception & Performance
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    • "Although subjective reports and neural measures of streaming have often been collected simultaneously (Cusack, 2005; Dykstra et al., 2011; Gutschalk et al., 2005; Hill et al., 2012; Snyder et al., 2006; Szalárdy et al., 2013), to our knowledge only one previous study has directly linked an objective measure of streaming with concurrent percept reports. Participants in Billig et al. (2013) heard sequences of repeated syllables that could be perceived as integrated or segregated due to spectral differences between the initial /s/ sound and the remainder (such as " stone " vs. " s " + " dohne " ). "
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    DESCRIPTION: Two experiments used subjective and objective measures to study the automaticity and primacy of auditory streaming. Listeners heard sequences of “ABA-” triplets, where “A” and “B” were tones of different frequencies and “-” was a silent gap. Segregation was more frequently reported, and rhythmically-deviant triplets less well-detected, for a greater between-tone frequency separation and later in the sequence. In Experiment 1, performing a competing auditory task for the first part of the sequence led to a reduction in subsequent streaming compared to when the tones were attended throughout. This is consistent with focused attention promoting streaming, and/or with attention switches resetting it. However, the proportion of segregated reports increased more rapidly following a switch than at the start of a sequence, indicating that some streaming occurred automatically. Modeling ruled out a simple “covert attention” account of this finding. Experiment 2 required listeners to perform subjective and objective tasks concurrently. It revealed superior performance during integrated compared to segregated reports, beyond that explained by the co-dependence of the two measures on stimulus parameters. We argue that listeners have limited access to low-level stimulus representations once perceptual organization has occurred, and that subjective and objective streaming measures partly index the same processes.
    Full-text · Research · Jul 2015
    • "The effect of the spatial distance on perceived similarity and streaming could further be tested, for example, by asking the participants to indicate whether they perceive streaming or not. However, this task would require the participant's attention, and it is known that stream segregation is influenceddat least to a certain extentdby attentional processes (Bregman, 1990; Pressnitzer and Hupé, 2006; Snyder et al., 2006). To circumvent the disadvantages of subjective-report procedures on the one hand, and of passive listening procedures (with the MMN as an indirect tool for investigating stream segregation outside the focus of attention) on the other hand, combined behavioral and ERPs measures (as recently proposed by Spielmann et al., 2014) could be used in future research. "
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    ABSTRACT: With age the ability to understand speech in multitalker environments usually deteriorates. The central auditory system has to perceptually segregate and group the acoustic input into sequences of distinct auditory objects. The present study used electrophysiological measures to study effects of age on auditory stream segregation in a multitalker scenario. Younger and older adults were presented with streams of short speech stimuli. When a single target stream was presented, the occurrence of a rare (deviant) syllable among a frequent (standard) syllable elicited the mismatch negativity (MMN), an electrophysiological correlate of automatic deviance detection. The presence of a second, concurrent stream consisting of the deviant syllable of the target stream reduced the MMN amplitude, especially when located nearby the target stream. The decrease in MMN amplitude indicates that the rare syllable of the target stream was less perceived as deviant, suggesting reduced stream segregation with decreasing stream distance. Moreover, the presence of a concurrent stream increased the MMN peak latency of the older group but not that of the younger group. The results provide neurophysiological evidence for the effects of concurrent speech on auditory processing in older adults, suggesting that older adults need more time for stream segregation in the presence of concurrent speech. Copyright © 2015 Elsevier Inc. All rights reserved.
    No preview · Article · Jul 2015 · Neurobiology of aging
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