Hemispheric asymmetry for spectral and temporal processing in the human antero-lateral auditory belt cortex. European Journal of Neuroscience, 22, 1521-1528

Faculty of Biosciences, University of Leipzig, Germany.
European Journal of Neuroscience (Impact Factor: 3.18). 10/2005; 22(6):1521-8. DOI: 10.1111/j.1460-9568.2005.04315.x
Source: PubMed


The present study investigates the acoustic basis of the hemispheric asymmetry for the processing of speech and music. Experiments on this question ideally involve stimuli that are perceptually unrelated to speech and music, but contain acoustic characteristics of both. Stimuli in previous studies were derived from speech samples or tonal sequences. Here we introduce a new class of noise-like sound stimuli with no resemblance of speech or music that permit independent parametric variation of spectral and temporal acoustic complexity. Using these stimuli in a functional MRI experiment, we test the hypothesis of a hemispheric asymmetry for the processing of spectral and temporal sound structure by seeking cortical areas in which the blood oxygen level dependent (BOLD) signal covaries with the number of simultaneous spectral components (spectral complexity) or the temporal modulation rate (temporal complexity) of the stimuli. BOLD-responses from the left and right Heschl's gyrus (HG) and part of the right superior temporal gyrus covaried with the spectral parameter, whereas covariation analysis for the temporal parameter highlighted an area on the left superior temporal gyrus. The portion of superior temporal gyrus in which asymmetrical responses are apparent corresponds to the antero-lateral auditory belt cortex, which has been implicated with spectral integration in animal studies. Our results support a similar function of the anterior auditory belt in humans. The findings indicate that asymmetrical processing of complex sounds in the cerebral hemispheres does not depend on semantic, but rather on acoustic stimulus characteristics.

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Available from: D. Y von Cramon, Oct 04, 2015
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    • "Neuroimaging studies revealed that the 'pitch extraction centers' are hosted in the lateral parts of HG (Patterson et al., 2002; Penagos et al., 2004; Warren et al., 2003), which are highlighted in Figure 1B. The left auditory cortex is specialized for rapid temporal and the right for spectral processing (Boemio et al., 2005; Hyde et al., 2008; Liegeois-Chauvel et al., 2001; Schönwiesner et al., 2005; Zatorre & Belin, 2001; Zatorre & Gandour, 2008). There are enormous inter-individual differences in terms of shape, gyration, size and number of duplications of HG. "
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    • "In the degraded condition of our experiment, we observed positive correlations of alpha power with BOLD activations in posterior STG and PT. The posterior STG and the PT have previously been suggested to subserve the processing of spectral information, and in particular, pitch and pitch changes (Zatorre et al., 1994; Zatorre and Belin, 2001; Schönwiesner et al., 2005; Hall and Plack, 2009; Alho et al., 2014). In particular, Hall and Plack (2009) provided evidence that apart from lateral Heschl's gyrus (Schneider et al., 2005; Warren et al., 2005), the (right) PT supports pitch processing to a substantial degree. "
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    ABSTRACT: Optimal utilization of acoustic cues during auditory categorization is a vital skill, particularly when informative cues become occluded or degraded. Consequently, the acoustic environment requires flexible choosing and switching amongst available cues. The present study targets the brain functions underlying such changes in cue utilization. Participants performed a categorization task with immediate feedback on acoustic stimuli from two categories that varied in duration and spectral properties, while we simultaneously recorded Blood Oxygenation Level Dependent (BOLD) responses in fMRI and electroencephalograms (EEGs). In the first half of the experiment, categories could be best discriminated by spectral properties. Halfway through the experiment, spectral degradation rendered the stimulus duration the more informative cue. Behaviorally, degradation decreased the likelihood of utilizing spectral cues. Spectrally degrading the acoustic signal led to increased alpha power compared to nondegraded stimuli. The EEG-informed fMRI analyses revealed that alpha power correlated with BOLD changes in inferior parietal cortex and right posterior superior temporal gyrus (including planum temporale). In both areas, spectral degradation led to a weaker coupling of BOLD response to behavioral utilization of the spectral cue. These data provide converging evidence from behavioral modeling, electrophysiology, and hemodynamics that (a) increased alpha power mediates the inhibition of uninformative (here spectral) stimulus features, and that (b) the parietal attention network supports optimal cue utilization in auditory categorization. The results highlight the complex cortical processing of auditory categorization under realistic listening challenges.
    Frontiers in Neuroscience 06/2014; 8(8):137. DOI:10.3389/fnins.2014.00137 · 3.66 Impact Factor
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    • "Several studies have utilized complex non-speech sounds in combination with temporal manipulation (e.g. Boemio et al., 2005; Schönwiesner et al., 2005); nevertheless, parametrically designed neuroimaging studies that employ natural speech as stimuli are scarce and are usually limited to very brief stimuli (Britton, Blumstein, Myers, & Grindrod, 2009). However, aforementioned prosodic elements are more pronounced, or only exist in speech exceeding the subsegmental level, for example sentences, as recently emphasized by McGettigan and Scott (2012). "
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    ABSTRACT: This study combines functional and structural magnetic resonance imaging to test the "asymmetric sampling in time" (AST) hypothesis, which makes assertions about the symmetrical and asymmetrical representation of speech in the primary and nonprimary auditory cortex. Twenty-three volunteers participated in this parametric clustered-sparse fMRI study. The availability of slowly changing acoustic cues in spoken sentences was systematically reduced over continuous segments with varying lengths (100, 150, 200, 250 ms) by utilizing local time-reversion. As predicted by the hypothesis, functional lateralization in Heschl's gyrus could not be observed. Lateralization in the planum temporale and posterior superior temporal gyrus shifted towards the right hemisphere with decreasing suprasegmental temporal integrity. Cortical thickness of the planum temporale was automatically measured. Participants with an L > R cortical thickness performed better on the in-scanner auditory pattern-matching task. Taken together, these findings support the AST hypothesis and provide substantial novel insight into the division of labor between left and right nonprimary auditory cortex functions during comprehension of spoken utterances. In addition, the present data yield support for a structural-behavioral relationship in the nonprimary auditory cortex. Hum Brain Mapp, 2013. © 2013 Wiley-Periodicals, Inc.
    Human Brain Mapping 04/2014; 35(4). DOI:10.1002/hbm.22291 · 5.97 Impact Factor
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