Categorical speech representation in human superior temporal gyrus

Chang, Edward F.; Rieger, Jochem W.; Johnson, Keith; Berger, Mitchel S.; Barbaro, Nicholas M.; Knight, Robert T.

doi:10.1038/nn.2641

Cited by 501 publications

(563 citation statements)

References 31 publications

(25 reference statements)

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“…Macaque PET imaging suggests there is also an evolutionary predisposition to left-hemisphere processing for conspecific communication calls (60). Consistent with macaque electrophysiology, human electrocorticography recordings from superior temporal gyrus (STG), in the region immediately posterior to the anterior-lateral aspect of Heschl's gyrus (i.e., mid-STG), show the site to code for phoneme identity at the population level (61). Mid-STG is also the site of peak high-gamma activity in response to CV sounds (62)(63)(64).…”

mentioning

confidence: 78%

Phoneme and word recognition in the auditory ventral stream

DeWitt

Rauschecker²

2012

Proc. Natl. Acad. Sci. U.S.A.

409

328

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Spoken word recognition requires complex, invariant representations. Using a meta-analytic approach incorporating more than 100 functional imaging experiments, we show that preference for complex sounds emerges in the human auditory ventral stream in a hierarchical fashion, consistent with nonhuman primate electrophysiology. Examining speech sounds, we show that activation associated with the processing of short-timescale patterns (i.e., phonemes) is consistently localized to left mid-superior temporal gyrus (STG), whereas activation associated with the integration of phonemes into temporally complex patterns (i.e., words) is consistently localized to left anterior STG. Further, we show left midto anterior STG is reliably implicated in the invariant representation of phonetic forms and that this area also responds preferentially to phonetic sounds, above artificial control sounds or environmental sounds. Together, this shows increasing encoding specificity and invariance along the auditory ventral stream for temporally complex speech sounds.functional MRI | meta-analysis | auditory cortex | object recognition | language S poken word recognition presents several challenges to the brain. Two key challenges are the assembly of complex auditory representations and the variability of natural speech (SI Appendix, Fig. S1) (1). Representation at the level of primary auditory cortex is precise: fine-grained in scale and local in spectrotemporal space (2, 3). The recognition of complex spectrotemporal forms, like words, in higher areas of auditory cortex requires the transformation of this granular representation into Gestalt-like, object-centered representations. In brief, local features must be bound together to form representations of complex spectrotemporal contours, which are themselves the constituents of auditory "objects" or complex sound patterns (4, 5). Next, representations must be generalized and abstracted. Coding in primary auditory cortex is sensitive even to minor physical transformations. Object-centered coding in higher areas, however, must be invariant (i.e., tolerant of natural stimulus variation) (6). For example, whereas the phonemic structure of a word is fixed, there is considerable variation in physical, spectrotemporal form-attributable to accent, pronunciation, body size, and the like-among utterances of a given word. It has been proposed for visual cortical processing that a feed-forward, hierarchical architecture (7) may be capable of simultaneously solving the problems of complexity and variability (8-12). Here, we examine these ideas in the context of auditory cortex.In a hierarchical pattern-recognition scheme (8), coding in the earliest cortical field would reflect the tuning and organization of primary auditory cortex (or core) (2, 3, 13). That is, single-neuron receptive fields (more precisely, frequency-response areas) would be tuned to particular center frequencies and would have minimal spectrotemporal complexity (i.e., a single excitatory zone and one-to-two inhibitory side bands). ...

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mentioning

confidence: 78%

Phoneme and word recognition in the auditory ventral stream

DeWitt

Rauschecker²

2012

Proc. Natl. Acad. Sci. U.S.A.

409

328

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“…P, posterior; A, anterior; L, left; R, right. Poldrack, 2007;Desai et al, 2008;Hutchison et al, 2008;Chang et al, 2010;Zevin et al, 2010;Kilian-Hütten et al, 2011). Nevertheless, theories implicating sensorimotor mapping in speech sound categorization (Devlin and Aydelott, 2009) suggest frontal regions should be involved as well.…”

Section: Discussionmentioning

confidence: 99%

“…The left posterior STG has been implicated in categorical phoneme perception by functional imaging (Husain et al, 2006;Desai et al, 2008;Hutchison et al, 2008) and intracranial human electrophysiology studies (Chang et al, 2010). The supramarginal gyrus (SMG) has also been implicated in categorical speech perception.…”

Section: Introductionmentioning

confidence: 99%

Categorical Speech Processing in Broca's Area: An fMRI Study Using Multivariate Pattern-Based Analysis

Lee¹,

Turkeltaub²,

Granger³

et al. 2012

J. Neurosci.

117

121

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Although much effort has been directed toward understanding the neural basis of speech processing, the neural processes involved in the categorical perception of speech have been relatively less studied, and many questions remain open. In this functional magnetic resonance imaging (fMRI) study, we probed the cortical regions mediating categorical speech perception using an advanced brain-mapping technique, whole-brain multivariate pattern-based analysis (MVPA). Normal healthy human subjects (native English speakers) were scanned while they listened to 10 consonant-vowel syllables along the /ba/-/da/ continuum. Outside of the scanner, individuals' own category boundaries were measured to divide the fMRI data into /ba/ and /da/ conditions per subject. The whole-brain MVPA revealed that Broca's area and the left pre-supplementary motor area evoked distinct neural activity patterns between the two perceptual categories (/ba/ vs /da/). Broca's area was also found when the same analysis was applied to another dataset (Raizada and Poldrack, 2007), which previously yielded the supramarginal gyrus using a univariate adaptation-fMRI paradigm. The consistent MVPA findings from two independent datasets strongly indicate that Broca's area participates in categorical speech perception, with a possible role of translating speech signals into articulatory codes. The difference in results between univariate and multivariate pattern-based analyses of the same data suggest that processes in different cortical areas along the dorsal speech perception stream are distributed on different spatial scales.

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“…They also show sensitivity to tiny acoustic differences that the father may not be able to consciously perceive and that may not even be important for understanding the message. 5,6 As the neural processing advances away from his superior temporal gyrus to other areas in the temporal lobe and toward left frontal brain areas, the representation of sounds appears to lose some of the fine-grained acoustic detail. Instead, it seems to represent something closer to what he actually is aware of hearing.…”

Section: The Lack Of Invariance Problemmentioning

confidence: 99%