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Luthra S, Razin RN, Tierney AT, Holt LL, Dick F. Systematic changes in neural selectivity reflect the acquired salience of category-diagnostic dimensions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.21.614258. [PMID: 39386708 PMCID: PMC11463673 DOI: 10.1101/2024.09.21.614258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
Humans and other animals develop remarkable behavioral specializations for identifying, differentiating, and acting on classes of ecologically important signals. Ultimately, this expertise is flexible enough to support diverse perceptual judgments: a voice, for example, simultaneously conveys what a talker says as well as myriad cues about her identity and state. Mature perception across complex signals thus involves both discovering and learning regularities that best inform diverse perceptual judgments, and weighting this information flexibly as task demands change. Here, we test whether this flexibility may involve endogenous attentional gain to task-relevant dimensions. We use two prospective auditory category learning tasks to relate a complex, entirely novel soundscape to four classes of "alien identity" and two classes of "alien size." Identity, but not size, categorization requires discovery and learning of patterned acoustic input situated in one of two simultaneous, frequency-delimited bands. This allows us to capitalize on the coarsely segregated frequency-band-specific channels of auditory tonotopic maps using fMRI to ask whether category-relevant perceptual information is prioritized relative to simultaneous, uninformative information. Among participants expert at alien identity categorization, we observe prioritization of the diagnostic frequency band that persists even when the diagnostic information becomes irrelevant in the size categorization task. Tellingly, the neural selectivity evoked implicitly in categorization aligns closely with activation driven by explicit, sustained selective attention to other sounds presented in the same frequency band. Additionally, we observe fingerprints of individual differences in the learning trajectories taken to achieve expert-level categorization in patterns of neural activity associated with the diagnostic dimension. In all, this indicates that acquiring categories can drive the emergence of acquired attentional salience to dimensions of acoustic input.
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Harford EE, Holt LL, Abel TJ. Unveiling the development of human voice perception: Neurobiological mechanisms and pathophysiology. CURRENT RESEARCH IN NEUROBIOLOGY 2024; 6:100127. [PMID: 38511174 PMCID: PMC10950757 DOI: 10.1016/j.crneur.2024.100127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/22/2024] [Accepted: 02/26/2024] [Indexed: 03/22/2024] Open
Abstract
The human voice is a critical stimulus for the auditory system that promotes social connection, informs the listener about identity and emotion, and acts as the carrier for spoken language. Research on voice processing in adults has informed our understanding of the unique status of the human voice in the mature auditory cortex and provided potential explanations for mechanisms that underly voice selectivity and identity processing. There is evidence that voice perception undergoes developmental change starting in infancy and extending through early adolescence. While even young infants recognize the voice of their mother, there is an apparent protracted course of development to reach adult-like selectivity for human voice over other sound categories and recognition of other talkers by voice. Gaps in the literature do not allow for an exact mapping of this trajectory or an adequate description of how voice processing and its neural underpinnings abilities evolve. This review provides a comprehensive account of developmental voice processing research published to date and discusses how this evidence fits with and contributes to current theoretical models proposed in the adult literature. We discuss how factors such as cognitive development, neural plasticity, perceptual narrowing, and language acquisition may contribute to the development of voice processing and its investigation in children. We also review evidence of voice processing abilities in premature birth, autism spectrum disorder, and phonagnosia to examine where and how deviations from the typical trajectory of development may manifest.
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Affiliation(s)
- Emily E. Harford
- Department of Neurological Surgery, University of Pittsburgh, USA
| | - Lori L. Holt
- Department of Psychology, The University of Texas at Austin, USA
| | - Taylor J. Abel
- Department of Neurological Surgery, University of Pittsburgh, USA
- Department of Bioengineering, University of Pittsburgh, USA
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3
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Incidental auditory category learning and visuomotor sequence learning do not compete for cognitive resources. Atten Percept Psychophys 2023; 85:452-462. [PMID: 36510102 DOI: 10.3758/s13414-022-02616-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2022] [Indexed: 12/15/2022]
Abstract
The environment provides multiple regularities that might be useful in guiding behavior if one was able to learn their structure. Understanding statistical learning across simultaneous regularities is important, but poorly understood. We investigate learning across two domains: visuomotor sequence learning through the serial reaction time (SRT) task, and incidental auditory category learning via the systematic multimodal association reaction time (SMART) task. Several commonalities raise the possibility that these two learning phenomena may draw on common cognitive resources and neural networks. In each, participants are uninformed of the regularities that they come to use to guide actions, the outcomes of which may provide a form of internal feedback. We used dual-task conditions to compare learning of the regularities in isolation versus when they are simultaneously available to support behavior on a seemingly orthogonal visuomotor task. Learning occurred across the simultaneous regularities, without attenuation even when the informational value of a regularity was reduced by the presence of the additional, convergent regularity. Thus, the simultaneous regularities do not compete for associative strength, as in overshadowing effects. Moreover, the visuomotor sequence learning and incidental auditory category learning do not appear to compete for common cognitive resources; learning across the simultaneous regularities was comparable to learning each regularity in isolation.
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Lim SJ, Thiel C, Sehm B, Deserno L, Lepsien J, Obleser J. Distributed networks for auditory memory differentially contribute to recall precision. Neuroimage 2022; 256:119227. [PMID: 35452804 DOI: 10.1016/j.neuroimage.2022.119227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 03/13/2022] [Accepted: 04/17/2022] [Indexed: 11/25/2022] Open
Abstract
Re-directing attention to objects in working memory can enhance their representational fidelity. However, how this attentional enhancement of memory representations is implemented across distinct, sensory and cognitive-control brain network is unspecified. The present fMRI experiment leverages psychophysical modelling and multivariate auditory-pattern decoding as behavioral and neural proxies of mnemonic fidelity. Listeners performed an auditory syllable pitch-discrimination task and received retro-active cues to selectively attend to a to-be-probed syllable in memory. Accompanied by increased neural activation in fronto-parietal and cingulo-opercular networks, valid retro-cues yielded faster and more perceptually sensitive responses in recalling acoustic detail of memorized syllables. Information about the cued auditory object was decodable from hemodynamic response patterns in superior temporal sulcus (STS), fronto-parietal, and sensorimotor regions. However, among these regions retaining auditory memory objects, neural fidelity in the left STS and its enhancement through attention-to-memory best predicted individuals' gain in auditory memory recall precision. Our results demonstrate how functionally discrete brain regions differentially contribute to the attentional enhancement of memory representations.
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Affiliation(s)
- Sung-Joo Lim
- Department of Psychology, University of Lübeck, Maria-Goeppert-Str. 9a, Lübeck 23562, Germany; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany; Department of Psychology, Binghamton University, State University of New York, 4400 Vestal Parkway E, Vestal, Binghamton, NY 13902, USA; Department of Speech, Language, and Hearing Sciences, Boston University, Boston, MA, USA.
| | - Christiane Thiel
- Department of Psychology, Carl von Ossietzky University of Oldenburg, Oldenburg 26129, Germany
| | - Bernhard Sehm
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany
| | - Lorenz Deserno
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany
| | - Jöran Lepsien
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany
| | - Jonas Obleser
- Department of Psychology, University of Lübeck, Maria-Goeppert-Str. 9a, Lübeck 23562, Germany; Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany; Center of Brain, Behavior, and Metabolism, University of Lübeck, Lübeck 23562, Germany.
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Abstract
Human speech perception results from neural computations that transform external acoustic speech signals into internal representations of words. The superior temporal gyrus (STG) contains the nonprimary auditory cortex and is a critical locus for phonological processing. Here, we describe how speech sound representation in the STG relies on fundamentally nonlinear and dynamical processes, such as categorization, normalization, contextual restoration, and the extraction of temporal structure. A spatial mosaic of local cortical sites on the STG exhibits complex auditory encoding for distinct acoustic-phonetic and prosodic features. We propose that as a population ensemble, these distributed patterns of neural activity give rise to abstract, higher-order phonemic and syllabic representations that support speech perception. This review presents a multi-scale, recurrent model of phonological processing in the STG, highlighting the critical interface between auditory and language systems.
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Affiliation(s)
- Ilina Bhaya-Grossman
- Department of Neurological Surgery, University of California, San Francisco, California 94143, USA;
- Joint Graduate Program in Bioengineering, University of California, Berkeley and San Francisco, California 94720, USA
| | - Edward F Chang
- Department of Neurological Surgery, University of California, San Francisco, California 94143, USA;
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6
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Ruthig P, Schönwiesner M. Common principles in the lateralisation of auditory cortex structure and function for vocal communication in primates and rodents. Eur J Neurosci 2022; 55:827-845. [PMID: 34984748 DOI: 10.1111/ejn.15590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 12/24/2021] [Indexed: 11/27/2022]
Abstract
This review summarises recent findings on the lateralisation of communicative sound processing in the auditory cortex (AC) of humans, non-human primates, and rodents. Functional imaging in humans has demonstrated a left hemispheric preference for some acoustic features of speech, but it is unclear to which degree this is caused by bottom-up acoustic feature selectivity or top-down modulation from language areas. Although non-human primates show a less pronounced functional lateralisation in AC, the properties of AC fields and behavioral asymmetries are qualitatively similar. Rodent studies demonstrate microstructural circuits that might underlie bottom-up acoustic feature selectivity in both hemispheres. Functionally, the left AC in the mouse appears to be specifically tuned to communication calls, whereas the right AC may have a more 'generalist' role. Rodents also show anatomical AC lateralisation, such as differences in size and connectivity. Several of these functional and anatomical characteristics are also lateralized in human AC. Thus, complex vocal communication processing shares common features among rodents and primates. We argue that a synthesis of results from humans, non-human primates, and rodents is necessary to identify the neural circuitry of vocal communication processing. However, data from different species and methods are often difficult to compare. Recent advances may enable better integration of methods across species. Efforts to standardise data formats and analysis tools would benefit comparative research and enable synergies between psychological and biological research in the area of vocal communication processing.
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Affiliation(s)
- Philip Ruthig
- Faculty of Life Sciences, Leipzig University, Leipzig, Sachsen.,Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig
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7
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Ekert JO, Gajardo-Vidal A, Lorca-Puls DL, Hope TMH, Dick F, Crinion JT, Green DW, Price CJ. Dissociating the functions of three left posterior superior temporal regions that contribute to speech perception and production. Neuroimage 2021; 245:118764. [PMID: 34848301 PMCID: PMC9125162 DOI: 10.1016/j.neuroimage.2021.118764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 11/15/2021] [Accepted: 11/24/2021] [Indexed: 11/28/2022] Open
Abstract
Prior studies have shown that the left posterior superior temporal sulcus (pSTS) and left temporo-parietal junction (TPJ) both contribute to phonological short-term memory, speech perception and speech production. Here, by conducting a within-subjects multi-factorial fMRI study, we dissociate the response profiles of these regions and a third region – the anterior ascending terminal branch of the left superior temporal sulcus (atSTS), which lies dorsal to pSTS and ventral to TPJ. First, we show that each region was more activated by (i) 1-back matching on visually presented verbal stimuli (words or pseudowords) compared to 1-back matching on visually presented non-verbal stimuli (pictures of objects or non-objects), and (ii) overt speech production than 1-back matching, across 8 types of stimuli (visually presented words, pseudowords, objects and non-objects and aurally presented words, pseudowords, object sounds and meaningless hums). The response properties of the three regions dissociated within the auditory modality. In left TPJ, activation was higher for auditory stimuli that were non-verbal (sounds of objects or meaningless hums) compared to verbal (words and pseudowords), irrespective of task (speech production or 1-back matching). In left pSTS, activation was higher for non-semantic stimuli (pseudowords and hums) than semantic stimuli (words and object sounds) on the dorsal pSTS surface (dpSTS), irrespective of task. In left atSTS, activation was not sensitive to either semantic or verbal content. The contrasting response properties of left TPJ, dpSTS and atSTS was cross-validated in an independent sample of 59 participants, using region-by-condition interactions. We also show that each region participates in non-overlapping networks of frontal, parietal and cerebellar regions. Our results challenge previous claims about functional specialisation in the left posterior superior temporal lobe and motivate future studies to determine the timing and directionality of information flow in the brain networks involved in speech perception and production.
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Affiliation(s)
- Justyna O Ekert
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, 12 Queen Square, London WC1N 3AR, United Kingdom.
| | - Andrea Gajardo-Vidal
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, 12 Queen Square, London WC1N 3AR, United Kingdom; Faculty of Health Sciences, Universidad del Desarrollo, Concepcion, Chile
| | - Diego L Lorca-Puls
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, 12 Queen Square, London WC1N 3AR, United Kingdom
| | - Thomas M H Hope
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, 12 Queen Square, London WC1N 3AR, United Kingdom
| | - Fred Dick
- Department of Experimental Psychology, University College London, London, United Kingdom; Department of Psychological Sciences, Birkbeck University of London, London, United Kingdom
| | - Jennifer T Crinion
- Institute of Cognitive Neuroscience, University College London, London, United Kingdom
| | - David W Green
- Department of Experimental Psychology, University College London, London, United Kingdom
| | - Cathy J Price
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, 12 Queen Square, London WC1N 3AR, United Kingdom
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8
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Feng G, Gan Z, Yi HG, Ell SW, Roark CL, Wang S, Wong PCM, Chandrasekaran B. Neural dynamics underlying the acquisition of distinct auditory category structures. Neuroimage 2021; 244:118565. [PMID: 34543762 PMCID: PMC8785192 DOI: 10.1016/j.neuroimage.2021.118565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 09/05/2021] [Accepted: 09/06/2021] [Indexed: 11/16/2022] Open
Abstract
Despite the multidimensional and temporally fleeting nature of auditory signals we quickly learn to assign novel sounds to behaviorally relevant categories. The neural systems underlying the learning and representation of novel auditory categories are far from understood. Current models argue for a rigid specialization of hierarchically organized core regions that are fine-tuned to extracting and mapping relevant auditory dimensions to meaningful categories. Scaffolded within a dual-learning systems approach, we test a competing hypothesis: the spatial and temporal dynamics of emerging auditory-category representations are not driven by the underlying dimensions but are constrained by category structure and learning strategies. To test these competing models, we used functional Magnetic Resonance Imaging (fMRI) to assess representational dynamics during the feedback-based acquisition of novel non-speech auditory categories with identical dimensions but differing category structures: rule-based (RB) categories, hypothesized to involve an explicit sound-to-rule mapping network, and information integration (II) based categories, involving pre-decisional integration of dimensions via a procedural-based sound-to-reward mapping network. Adults were assigned to either the RB (n = 30, 19 females) or II (n = 30, 22 females) learning tasks. Despite similar behavioral learning accuracies, learning strategies derived from computational modeling and involvements of corticostriatal systems during feedback processing differed across tasks. Spatiotemporal multivariate representational similarity analysis revealed an emerging representation within an auditory sensory-motor pathway exclusively for the II learning task, prominently involving the superior temporal gyrus (STG), inferior frontal gyrus (IFG), and posterior precentral gyrus. In contrast, the RB learning task yielded distributed neural representations within regions involved in cognitive-control and attentional processes that emerged at different time points of learning. Our results unequivocally demonstrate that auditory learners' neural systems are highly flexible and show distinct spatial and temporal patterns that are not dimension-specific but reflect underlying category structures and learning strategies.
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Affiliation(s)
- Gangyi Feng
- Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Brain and Mind Institute, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
| | - Zhenzhong Gan
- Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education, China, School of Psychology, Center for Studies of Psychological Application, and Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou 510631, China
| | - Han Gyol Yi
- Department of Neurological Surgery, University of California, San Francisco, CA 94158, United States
| | - Shawn W Ell
- Department of Psychology, Graduate School of Biomedical Sciences and Engineering, University of Maine, 5742 Little Hall, Room 301, Orono, ME 04469-5742, United States
| | - Casey L Roark
- Department of Communication Science and Disorders, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States; Center for the Neural Basis of Cognition, Pittsburgh, PA 15232, United States
| | - Suiping Wang
- Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education, China, School of Psychology, Center for Studies of Psychological Application, and Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou 510631, China
| | - Patrick C M Wong
- Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Brain and Mind Institute, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Bharath Chandrasekaran
- Department of Communication Science and Disorders, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States; Center for the Neural Basis of Cognition, Pittsburgh, PA 15232, United States.
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9
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Learning nonnative speech sounds changes local encoding in the adult human cortex. Proc Natl Acad Sci U S A 2021; 118:2101777118. [PMID: 34475209 DOI: 10.1073/pnas.2101777118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 07/12/2021] [Indexed: 11/18/2022] Open
Abstract
Adults can learn to identify nonnative speech sounds with training, albeit with substantial variability in learning behavior. Increases in behavioral accuracy are associated with increased separability for sound representations in cortical speech areas. However, it remains unclear whether individual auditory neural populations all show the same types of changes with learning, or whether there are heterogeneous encoding patterns. Here, we used high-resolution direct neural recordings to examine local population response patterns, while native English listeners learned to recognize unfamiliar vocal pitch patterns in Mandarin Chinese tones. We found a distributed set of neural populations in bilateral superior temporal gyrus and ventrolateral frontal cortex, where the encoding of Mandarin tones changed throughout training as a function of trial-by-trial accuracy ("learning effect"), including both increases and decreases in the separability of tones. These populations were distinct from populations that showed changes as a function of exposure to the stimuli regardless of trial-by-trial accuracy. These learning effects were driven in part by more variable neural responses to repeated presentations of acoustically identical stimuli. Finally, learning effects could be predicted from speech-evoked activity even before training, suggesting that intrinsic properties of these populations make them amenable to behavior-related changes. Together, these results demonstrate that nonnative speech sound learning involves a wide array of changes in neural representations across a distributed set of brain regions.
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10
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Feng G, Gan Z, Llanos F, Meng D, Wang S, Wong PCM, Chandrasekaran B. A distributed dynamic brain network mediates linguistic tone representation and categorization. Neuroimage 2021; 224:117410. [PMID: 33011415 PMCID: PMC7749825 DOI: 10.1016/j.neuroimage.2020.117410] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/21/2020] [Accepted: 09/25/2020] [Indexed: 12/21/2022] Open
Abstract
Successful categorization requires listeners to represent the incoming sensory information, resolve the "blooming, buzzing confusion" inherent to noisy sensory signals, and leverage the accumulated evidence towards making a decision. Despite decades of intense debate, the neural systems underlying speech categorization remain unresolved. Here we assessed the neural representation and categorization of lexical tones by native Mandarin speakers (N = 31) across a range of acoustic and contextual variabilities (talkers, perceptual saliences, and stimulus-contexts) using functional magnetic imaging (fMRI) and an evidence accumulation model of decision-making. Univariate activation and multivariate pattern analyses reveal that the acoustic-variability-tolerant representations of tone category are observed within the middle portion of the left superior temporal gyrus (STG). Activation patterns in the frontal and parietal regions also contained category-relevant information that was differentially sensitive to various forms of variability. The robustness of neural representations of tone category in a distributed fronto-temporoparietal network is associated with trial-by-trial decision-making parameters. These findings support a hybrid model involving a representational core within the STG that operates dynamically within an extensive frontoparietal network to support the representation and categorization of linguistic pitch patterns.
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Affiliation(s)
- Gangyi Feng
- Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Brain and Mind Institute, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China.
| | - Zhenzhong Gan
- Center for the Study of Applied Psychology and School of Psychology, South China Normal University, Guangzhou 510631, China
| | - Fernando Llanos
- Department of Communication Science and Disorders, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Danting Meng
- Center for the Study of Applied Psychology and School of Psychology, South China Normal University, Guangzhou 510631, China
| | - Suiping Wang
- Center for the Study of Applied Psychology and School of Psychology, South China Normal University, Guangzhou 510631, China; Guangdong Provincial Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou 510631, China
| | - Patrick C M Wong
- Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China; Brain and Mind Institute, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Bharath Chandrasekaran
- Department of Communication Science and Disorders, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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11
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Marklund E, Gustavsson L, Kallioinen P, Schwarz IC. N1 Repetition-Attenuation for Acoustically Variable Speech and Spectrally Rotated Speech. Front Hum Neurosci 2020; 14:534804. [PMID: 33192385 PMCID: PMC7658466 DOI: 10.3389/fnhum.2020.534804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 09/22/2020] [Indexed: 11/13/2022] Open
Abstract
The amplitude of the event-related N1 wave decreases with repeated stimulation. This repetition-attenuation has not previously been investigated in response to variable auditory stimuli, nor has the relative impact of acoustic vs. perceptual category repetition been studied. In the present study, N1 repetition-attenuation was investigated for speech and spectrally rotated speech with varying degrees of acoustic and perceptual category variation. In the speech condition, participants (n = 19) listened to stimulus trains consisting of either the same vowel exemplar (no variability condition), different exemplars of the same vowel (low variability condition), or different exemplars of two different vowels (high variability condition). In the rotated speech condition, the spectrally rotated counterparts of the vowels were presented. Findings show N1 repetition-attenuation in the face of acoustic and perceptual category variability, but no impact of the degree of variability on the degree of N1 attenuation. Speech stimuli resulted in less attenuation than the acoustically matched non-speech stimuli, which is in line with previous findings. It remains unclear if the attenuation of the N1 wave is reduced as a result of stimuli being perceived as belonging to perceptual categories or as a result of some other characteristic of speech.
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12
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Feng G, Yi HG, Chandrasekaran B. The Role of the Human Auditory Corticostriatal Network in Speech Learning. Cereb Cortex 2020; 29:4077-4089. [PMID: 30535138 DOI: 10.1093/cercor/bhy289] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 08/30/2018] [Indexed: 01/26/2023] Open
Abstract
We establish a mechanistic account of how the mature human brain functionally reorganizes to acquire and represent new speech sounds. Native speakers of English learned to categorize Mandarin lexical tone categories produced by multiple talkers using trial-by-trial feedback. We hypothesized that the corticostriatal system is a key intermediary in mediating temporal lobe plasticity and the acquisition of new speech categories in adulthood. We conducted a functional magnetic resonance imaging experiment in which participants underwent a sound-to-category mapping task. Diffusion tensor imaging data were collected, and probabilistic fiber tracking analysis was employed to assay the auditory corticostriatal pathways. Multivariate pattern analysis showed that talker-invariant novel tone category representations emerged in the left superior temporal gyrus (LSTG) within a few hundred training trials. Univariate analysis showed that the putamen, a subregion of the striatum, was sensitive to positive feedback in correctly categorized trials. With learning, functional coupling between the putamen and LSTG increased during error processing. Furthermore, fiber tractography demonstrated robust structural connectivity between the feedback-sensitive striatal regions and the LSTG regions that represent the newly learned tone categories. Our convergent findings highlight a critical role for the auditory corticostriatal circuitry in mediating the acquisition of new speech categories.
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Affiliation(s)
- Gangyi Feng
- Department of Linguistics and Modern Languages, The Chinese University of Hong Kong, Hong Kong SAR, China.,Brain and Mind Institute, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Han Gyol Yi
- Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Bharath Chandrasekaran
- Department of Communication Science and Disorders, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA
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13
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Luthra S, Fuhrmeister P, Molfese PJ, Guediche S, Blumstein SE, Myers EB. Brain-behavior relationships in incidental learning of non-native phonetic categories. BRAIN AND LANGUAGE 2019; 198:104692. [PMID: 31522094 PMCID: PMC6773471 DOI: 10.1016/j.bandl.2019.104692] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 08/29/2019] [Accepted: 09/01/2019] [Indexed: 06/01/2023]
Abstract
Research has implicated the left inferior frontal gyrus (LIFG) in mapping acoustic-phonetic input to sound category representations, both in native speech perception and non-native phonetic category learning. At issue is whether this sensitivity reflects access to phonetic category information per se or to explicit category labels, the latter often being required by experimental procedures. The current study employed an incidental learning paradigm designed to increase sensitivity to a difficult non-native phonetic contrast without inducing explicit awareness of the categorical nature of the stimuli. Functional MRI scans revealed frontal sensitivity to phonetic category structure both before and after learning. Additionally, individuals who succeeded most on the learning task showed the largest increases in frontal recruitment after learning. Overall, results suggest that processing novel phonetic category information entails a reliance on frontal brain regions, even in the absence of explicit category labels.
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Affiliation(s)
- Sahil Luthra
- University of Connecticut, Department of Psychological Sciences, United States.
| | - Pamela Fuhrmeister
- University of Connecticut, Department of Speech, Language and Hearing Sciences, United States.
| | | | - Sara Guediche
- Basque Center on Cognition, Brain and Language, Spain.
| | - Sheila E Blumstein
- Brown University, Department of Cognitive, Linguistic and Psychological Sciences, United States.
| | - Emily B Myers
- University of Connecticut, Department of Psychological Sciences, United States; University of Connecticut, Department of Speech, Language and Hearing Sciences, United States; Haskins Laboratories, United States.
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14
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Training Humans to Categorize Monkey Calls: Auditory Feature- and Category-Selective Neural Tuning Changes. Neuron 2019; 98:405-416.e4. [PMID: 29673483 DOI: 10.1016/j.neuron.2018.03.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 01/18/2018] [Accepted: 03/08/2018] [Indexed: 11/23/2022]
Abstract
Grouping auditory stimuli into common categories is essential for a variety of auditory tasks, including speech recognition. We trained human participants to categorize auditory stimuli from a large novel set of morphed monkey vocalizations. Using fMRI-rapid adaptation (fMRI-RA) and multi-voxel pattern analysis (MVPA) techniques, we gained evidence that categorization training results in two distinct sets of changes: sharpened tuning to monkey call features (without explicit category representation) in left auditory cortex and category selectivity for different types of calls in lateral prefrontal cortex. In addition, the sharpness of neural selectivity in left auditory cortex, as estimated with both fMRI-RA and MVPA, predicted the steepness of the categorical boundary, whereas categorical judgment correlated with release from adaptation in the left inferior frontal gyrus. These results support the theory that auditory category learning follows a two-stage model analogous to the visual domain, suggesting general principles of perceptual category learning in the human brain.
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Neural processes of vocal social perception: Dog-human comparative fMRI studies. Neurosci Biobehav Rev 2019; 85:54-64. [PMID: 29287629 DOI: 10.1016/j.neubiorev.2017.11.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 11/20/2017] [Accepted: 11/23/2017] [Indexed: 11/20/2022]
Abstract
In this review we focus on the exciting new opportunities in comparative neuroscience to study neural processes of vocal social perception by comparing dog and human neural activity using fMRI methods. The dog is a relatively new addition to this research area; however, it has a large potential to become a standard species in such investigations. Although there has been great interest in the emergence of human language abilities, in case of fMRI methods, most research to date focused on homologue comparisons within Primates. By belonging to a very different clade of mammalian evolution, dogs could give such research agendas a more general mammalian foundation. In addition, broadening the scope of investigations into vocal communication in general can also deepen our understanding of human vocal skills. Being selected for and living in an anthropogenic environment, research with dogs may also be informative about the way in which human non-linguistic and linguistic signals are represented in a mammalian brain without skills for language production.
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Abstract
Humans are born as “universal listeners.” However, over the first year, infants’ perception is shaped by native speech categories. How do these categories naturally emerge without explicit training or overt feedback? Using fMRI, we examined the neural basis of incidental sound category learning as participants played a videogame in which sound category exemplars had functional utility in guiding videogame success. Even without explicit categorization of the sounds, participants learned functionally relevant sound categories that generalized to novel exemplars when exemplars had an organized distributional structure. Critically, the striatum was engaged and functionally connected to the auditory cortex during game play, and this activity and connectivity predicted the learning outcome. These findings elucidate the neural mechanism by which humans incidentally learn “real-world” categories. Humans are born as “universal listeners” without a bias toward any particular language. However, over the first year of life, infants’ perception is shaped by learning native speech categories. Acoustically different sounds—such as the same word produced by different speakers—come to be treated as functionally equivalent. In natural environments, these categories often emerge incidentally without overt categorization or explicit feedback. However, the neural substrates of category learning have been investigated almost exclusively using overt categorization tasks with explicit feedback about categorization decisions. Here, we examined whether the striatum, previously implicated in category learning, contributes to incidental acquisition of sound categories. In the fMRI scanner, participants played a videogame in which sound category exemplars aligned with game actions and events, allowing sound categories to incidentally support successful game play. An experimental group heard nonspeech sound exemplars drawn from coherent category spaces, whereas a control group heard acoustically similar sounds drawn from a less structured space. Although the groups exhibited similar in-game performance, generalization of sound category learning and activation of the posterior striatum were significantly greater in the experimental than control group. Moreover, the experimental group showed brain–behavior relationships related to the generalization of all categories, while in the control group these relationships were restricted to the categories with structured sound distributions. Together, these results demonstrate that the striatum, through its interactions with the left superior temporal sulcus, contributes to incidental acquisition of sound category representations emerging from naturalistic learning environments.
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Disentangling phonological and articulatory processing: A neuroanatomical study in aphasia. Neuropsychologia 2018; 121:175-185. [DOI: 10.1016/j.neuropsychologia.2018.10.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 11/24/2022]
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18
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Price CJ. The evolution of cognitive models: From neuropsychology to neuroimaging and back. Cortex 2018; 107:37-49. [PMID: 29373117 PMCID: PMC5924872 DOI: 10.1016/j.cortex.2017.12.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 12/18/2017] [Accepted: 12/19/2017] [Indexed: 12/24/2022]
Abstract
This paper provides a historical and future perspective on how neuropsychology and neuroimaging can be used to develop cognitive models of human brain functions. Section 1 focuses on the emergence of cognitive modelling from neuropsychology, why lesion location was considered to be unimportant and the challenges faced when mapping symptoms to impaired cognitive processes. Section 2 describes how established cognitive models based on behavioural data alone cannot explain the complex patterns of distributed brain activity that are observed in functional neuroimaging studies. This has led to proposals for new cognitive processes, new cognitive strategies and new functional ontologies for cognition. Section 3 considers how the integration of data from lesion, behavioural and functional neuroimaging studies of large cohorts of brain damaged patients can be used to determine whether inter-patient variability in behaviour is due to differences in the premorbid function of each brain region, lesion site or cognitive strategy. This combination of neuroimaging and neuropsychology is providing a deeper understanding of how cognitive functions can be lost and re-learnt after brain damage - an understanding that will transform our ability to generate and validate cognitive models that are both physiologically plausible and clinically useful.
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Affiliation(s)
- Cathy J Price
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, London, UK.
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19
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Holt LL, Tierney AT, Guerra G, Laffere A, Dick F. Dimension-selective attention as a possible driver of dynamic, context-dependent re-weighting in speech processing. Hear Res 2018; 366:50-64. [PMID: 30131109 PMCID: PMC6107307 DOI: 10.1016/j.heares.2018.06.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 06/10/2018] [Accepted: 06/19/2018] [Indexed: 12/24/2022]
Abstract
The contribution of acoustic dimensions to an auditory percept is dynamically adjusted and reweighted based on prior experience about how informative these dimensions are across the long-term and short-term environment. This is especially evident in speech perception, where listeners differentially weight information across multiple acoustic dimensions, and use this information selectively to update expectations about future sounds. The dynamic and selective adjustment of how acoustic input dimensions contribute to perception has made it tempting to conceive of this as a form of non-spatial auditory selective attention. Here, we review several human speech perception phenomena that might be consistent with auditory selective attention although, as of yet, the literature does not definitively support a mechanistic tie. We relate these human perceptual phenomena to illustrative nonhuman animal neurobiological findings that offer informative guideposts in how to test mechanistic connections. We next present a novel empirical approach that can serve as a methodological bridge from human research to animal neurobiological studies. Finally, we describe four preliminary results that demonstrate its utility in advancing understanding of human non-spatial dimension-based auditory selective attention.
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Affiliation(s)
- Lori L Holt
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA, 15213, USA; Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
| | - Adam T Tierney
- Department of Psychological Sciences, Birkbeck College, University of London, London, WC1E 7HX, UK; Centre for Brain and Cognitive Development, Birkbeck College, London, WC1E 7HX, UK
| | - Giada Guerra
- Department of Psychological Sciences, Birkbeck College, University of London, London, WC1E 7HX, UK; Centre for Brain and Cognitive Development, Birkbeck College, London, WC1E 7HX, UK
| | - Aeron Laffere
- Department of Psychological Sciences, Birkbeck College, University of London, London, WC1E 7HX, UK
| | - Frederic Dick
- Department of Psychological Sciences, Birkbeck College, University of London, London, WC1E 7HX, UK; Centre for Brain and Cognitive Development, Birkbeck College, London, WC1E 7HX, UK; Department of Experimental Psychology, University College London, London, WC1H 0AP, UK
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20
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Alemi R, Batouli SAH, Behzad E, Ebrahimpoor M, Oghabian MA. Not single brain areas but a network is involved in language: Applications in presurgical planning. Clin Neurol Neurosurg 2018; 165:116-128. [PMID: 29334640 DOI: 10.1016/j.clineuro.2018.01.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/03/2018] [Accepted: 01/08/2018] [Indexed: 01/22/2023]
Abstract
OBJECTIVES Language is an important human function, and is a determinant of the quality of life. In conditions such as brain lesions, disruption of the language function may occur, and lesion resection is a solution for that. Presurgical planning to determine the language-related brain areas would enhance the chances of language preservation after the operation; however, availability of a normative language template is essential. PATIENTS AND METHODS In this study, using data from 60 young individuals who were meticulously checked for mental and physical health, and using fMRI and robust imaging and data analysis methods, functional brain maps for the language production, perception and semantic were produced. RESULTS The obtained templates showed that the language function should be considered as the product of the collaboration of a network of brain regions, instead of considering only few brain areas to be involved in that. CONCLUSION This study has important clinical applications, and extends our knowledge on the neuroanatomy of the language function.
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Affiliation(s)
- Razieh Alemi
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran; Department of Otorhinolaryngology, Faculty of Medicine, McGill University, Canada
| | - Seyed Amir Hossein Batouli
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran; Neuroimaging and Analysis Group, Tehran University of Medical Sciences, Tehran, Iran
| | - Ebrahim Behzad
- Department of Neuroscience and Addiction Studies, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mitra Ebrahimpoor
- Neuroimaging and Analysis Group, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Ali Oghabian
- Neuroimaging and Analysis Group, Tehran University of Medical Sciences, Tehran, Iran; Medical Physics and Biomedical Engineering Department, Tehran University of Medical Sciences, Tehran, Iran.
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Carey D, Miquel ME, Evans BG, Adank P, McGettigan C. Functional brain outcomes of L2 speech learning emerge during sensorimotor transformation. Neuroimage 2017; 159:18-31. [PMID: 28669904 DOI: 10.1016/j.neuroimage.2017.06.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 11/18/2022] Open
Abstract
Sensorimotor transformation (ST) may be a critical process in mapping perceived speech input onto non-native (L2) phonemes, in support of subsequent speech production. Yet, little is known concerning the role of ST with respect to L2 speech, particularly where learned L2 phones (e.g., vowels) must be produced in more complex lexical contexts (e.g., multi-syllabic words). Here, we charted the behavioral and neural outcomes of producing trained L2 vowels at word level, using a speech imitation paradigm and functional MRI. We asked whether participants would be able to faithfully imitate trained L2 vowels when they occurred in non-words of varying complexity (one or three syllables). Moreover, we related individual differences in imitation success during training to BOLD activation during ST (i.e., pre-imitation listening), and during later imitation. We predicted that superior temporal and peri-Sylvian speech regions would show increased activation as a function of item complexity and non-nativeness of vowels, during ST. We further anticipated that pre-scan acoustic learning performance would predict BOLD activation for non-native (vs. native) speech during ST and imitation. We found individual differences in imitation success for training on the non-native vowel tokens in isolation; these were preserved in a subsequent task, during imitation of mono- and trisyllabic words containing those vowels. fMRI data revealed a widespread network involved in ST, modulated by both vowel nativeness and utterance complexity: superior temporal activation increased monotonically with complexity, showing greater activation for non-native than native vowels when presented in isolation and in trisyllables, but not in monosyllables. Individual differences analyses showed that learning versus lack of improvement on the non-native vowel during pre-scan training predicted increased ST activation for non-native compared with native items, at insular cortex, pre-SMA/SMA, and cerebellum. Our results hold implications for the importance of ST as a process underlying successful imitation of non-native speech.
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Affiliation(s)
- Daniel Carey
- Department of Psychology, Royal Holloway, University of London, TW20 0EX, UK; Combined Universities Brain Imaging Centre, Royal Holloway, University of London, TW20 0EX, UK; The Irish Longitudinal Study on Ageing (TILDA), Dept. Medical Gerontology, TCD, Dublin, Ireland
| | - Marc E Miquel
- William Harvey Research Institute, Queen Mary, University of London, EC1M 6BQ, UK; Clinical Physics, Barts Health NHS Trust, London, EC1A 7BE, UK
| | - Bronwen G Evans
- Department of Speech, Hearing & Phonetic Sciences, University College London, WC1E 6BT, UK
| | - Patti Adank
- Department of Speech, Hearing & Phonetic Sciences, University College London, WC1E 6BT, UK
| | - Carolyn McGettigan
- Department of Psychology, Royal Holloway, University of London, TW20 0EX, UK; Combined Universities Brain Imaging Centre, Royal Holloway, University of London, TW20 0EX, UK; Institute of Cognitive Neuroscience, University College London, WC1N 3AR, UK.
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Stimulating Multiple-Demand Cortex Enhances Vocabulary Learning. J Neurosci 2017; 37:7606-7618. [PMID: 28676576 PMCID: PMC5551060 DOI: 10.1523/jneurosci.3857-16.2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 04/20/2017] [Accepted: 04/27/2017] [Indexed: 01/04/2023] Open
Abstract
It is well established that networks within multiple-demand cortex (MDC) become active when diverse skills and behaviors are being learnt. However, their causal role in learning remains to be established. In the present study, we first performed functional magnetic resonance imaging on healthy female and male human participants to confirm that MDC was most active in the initial stages of learning a novel vocabulary, consisting of pronounceable nonwords (pseudowords), each associated with a picture of a real object. We then examined, in healthy female and male human participants, whether repetitive transcranial magnetic stimulation of a frontal midline node of the cingulo-opercular MDC affected learning rates specifically during the initial stages of learning. We report that stimulation of this node, but not a control brain region, substantially improved both accuracy and response times during the earliest stage of learning pseudoword–object associations. This stimulation had no effect on the processing of established vocabulary, tested by the accuracy and response times when participants decided whether a real word was accurately paired with a picture of an object. These results provide evidence that noninvasive stimulation to MDC nodes can enhance learning rates, thereby demonstrating their causal role in the learning process. We propose that this causal role makes MDC candidate target for experimental therapeutics; for example, in stroke patients with aphasia attempting to reacquire a vocabulary. SIGNIFICANCE STATEMENT Learning a task involves the brain system within which that specific task becomes established. Therefore, successfully learning a new vocabulary establishes the novel words in the language system. However, there is evidence that in the early stages of learning, networks within multiple-demand cortex (MDC), which control higher cognitive functions, such as working memory, attention, and monitoring of performance, become active. This activity declines once the task is learnt. The present study demonstrated that a node within MDC, located in midline frontal cortex, becomes active during the early stage of learning a novel vocabulary. Importantly, noninvasive brain stimulation of this node improved performance during this stage of learning. This observation demonstrated that MDC activity is important for learning.
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23
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Flaherty M, Dent ML, Sawusch JR. Experience with speech sounds is not necessary for cue trading by budgerigars (Melopsittacus undulatus). PLoS One 2017; 12:e0177676. [PMID: 28562597 PMCID: PMC5451017 DOI: 10.1371/journal.pone.0177676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 05/01/2017] [Indexed: 11/18/2022] Open
Abstract
The influence of experience with human speech sounds on speech perception in budgerigars, vocal mimics whose speech exposure can be tightly controlled in a laboratory setting, was measured. Budgerigars were divided into groups that differed in auditory exposure and then tested on a cue-trading identification paradigm with synthetic speech. Phonetic cue trading is a perceptual phenomenon observed when changes on one cue dimension are offset by changes in another cue dimension while still maintaining the same phonetic percept. The current study examined whether budgerigars would trade the cues of voice onset time (VOT) and the first formant onset frequency when identifying syllable initial stop consonants and if this would be influenced by exposure to speech sounds. There were a total of four different exposure groups: No speech exposure (completely isolated), Passive speech exposure (regular exposure to human speech), and two Speech-trained groups. After the exposure period, all budgerigars were tested for phonetic cue trading using operant conditioning procedures. Birds were trained to peck keys in response to different synthetic speech sounds that began with "d" or "t" and varied in VOT and frequency of the first formant at voicing onset. Once training performance criteria were met, budgerigars were presented with the entire intermediate series, including ambiguous sounds. Responses on these trials were used to determine which speech cues were used, if a trading relation between VOT and the onset frequency of the first formant was present, and whether speech exposure had an influence on perception. Cue trading was found in all birds and these results were largely similar to those of a group of humans. Results indicated that prior speech experience was not a requirement for cue trading by budgerigars. The results are consistent with theories that explain phonetic cue trading in terms of a rich auditory encoding of the speech signal.
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Affiliation(s)
- Mary Flaherty
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
| | - Micheal L. Dent
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
- * E-mail:
| | - James R. Sawusch
- Department of Psychology, University at Buffalo, The State University of New York, Buffalo, New York, United States of America
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Alcalá-López D, Smallwood J, Jefferies E, Van Overwalle F, Vogeley K, Mars RB, Turetsky BI, Laird AR, Fox PT, Eickhoff SB, Bzdok D. Computing the Social Brain Connectome Across Systems and States. Cereb Cortex 2017; 28:2207-2232. [DOI: 10.1093/cercor/bhx121] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 04/27/2017] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel Alcalá-López
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany
| | - Jonathan Smallwood
- Department of Psychology, York Neuroimaging Centre, University of York, Hesslington, York, UK
| | - Elizabeth Jefferies
- Department of Psychology, York Neuroimaging Centre, University of York, Hesslington, York, UK
| | | | - Kai Vogeley
- Department of Psychiatry and Psychotherapy, University Hospital Cologne, Cologne, Germany
| | - Rogier B Mars
- Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6525 EZ Nijmegen, The Netherlands
| | - Bruce I Turetsky
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA
| | - Angela R Laird
- Department of Physics, Florida International University, Miami, FL, USA
| | - Peter T Fox
- Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, USA
| | - Simon B Eickhoff
- Medical Faculty, Institute for Systems Neuroscience, Heinrich-Heine University, Düsseldorf, Germany
- Institute for Neuroscience and Medicine (INM-7, Brain & Behavior), Research Center Jülich, Jülich, Germany
| | - Danilo Bzdok
- Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany
- Parietal Team, INRIA, Neurospin, bat 145, CEA Saclay, Gif-sur-Yvette, France
- JARA, Translational Brain Medicine, Aachen, Germany
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25
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Eigsti IM, Stevens MC, Schultz RT, Barton M, Kelley E, Naigles L, Orinstein A, Troyb E, Fein DA. Language comprehension and brain function in individuals with an optimal outcome from autism. NEUROIMAGE-CLINICAL 2015; 10:182-91. [PMID: 26862477 PMCID: PMC4707189 DOI: 10.1016/j.nicl.2015.11.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 09/23/2015] [Accepted: 11/16/2015] [Indexed: 11/30/2022]
Abstract
Although Autism Spectrum Disorder (ASD) is generally a lifelong disability, a minority of individuals with ASD overcome their symptoms to such a degree that they are generally indistinguishable from their typically-developing peers. That is, they have achieved an Optimal Outcome (OO). The question addressed by the current study is whether this normalized behavior reflects normalized brain functioning, or alternatively, the action of compensatory systems. Either possibility is plausible, as most participants with OO received years of intensive therapy that could alter brain networks to align with typical function or work around ASD-related neural dysfunction. Individuals ages 8 to 21 years with high-functioning ASD (n = 23), OO (n = 16), or typical development (TD; n = 20) completed a functional MRI scan while performing a sentence comprehension task. Results indicated similar activations in frontal and temporal regions (left middle frontal, left supramarginal, and right superior temporal gyri) and posterior cingulate in OO and ASD groups, where both differed from the TD group. Furthermore, the OO group showed heightened “compensatory” activation in numerous left- and right-lateralized regions (left precentral/postcentral gyri, right precentral gyrus, left inferior parietal lobule, right supramarginal gyrus, left superior temporal/parahippocampal gyrus, left middle occipital gyrus) and cerebellum, relative to both ASD and TD groups. Behaviorally normalized language abilities in OO individuals appear to utilize atypical brain networks, with increased recruitment of language-specific as well as right homologue and other systems. Early intensive learning and experience may normalize behavioral language performance in OO, but some brain regions involved in language processing may continue to display characteristics that are more similar to ASD than typical development, while others show characteristics not like ASD or typical development. fMRI study of "optimal outcome" (OO) youth with no symptoms of autism spectrum disorder. Results show “compensatory” language activation in some areas in OO. OO youth also had some “residual ASD” patterns of activation (OO, ASD > TD). There was no evidence of areas of normalized brain function (OO, TD ≠ ASD). Early treatment may normalize behavior but not brain in some individuals with ASD.
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Affiliation(s)
- Inge-Marie Eigsti
- Department of Psychology, University of Connecticut, Storrs, CT, USA
| | | | - Robert T Schultz
- Center for Autism Research, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Marianne Barton
- Department of Psychology, University of Connecticut, Storrs, CT, USA
| | - Elizabeth Kelley
- Department of Psychology, Queen's University, Kingston, ON, Canada
| | - Letitia Naigles
- Department of Psychology, University of Connecticut, Storrs, CT, USA
| | - Alyssa Orinstein
- Department of Psychology, University of Connecticut, Storrs, CT, USA
| | - Eva Troyb
- Department of Psychology, University of Connecticut, Storrs, CT, USA
| | - Deborah A Fein
- Department of Psychology, University of Connecticut, Storrs, CT, USA; Department of Pediatrics, University of Connecticut, Farmington, CT, USA
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26
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From bird to sparrow: Learning-induced modulations in fine-grained semantic discrimination. Neuroimage 2015; 118:163-73. [DOI: 10.1016/j.neuroimage.2015.05.091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 05/02/2015] [Accepted: 05/25/2015] [Indexed: 11/23/2022] Open
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Gabay Y, Holt LL. Incidental learning of sound categories is impaired in developmental dyslexia. Cortex 2015; 73:131-43. [PMID: 26409017 DOI: 10.1016/j.cortex.2015.08.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/09/2015] [Accepted: 08/07/2015] [Indexed: 11/29/2022]
Abstract
Developmental dyslexia is commonly thought to arise from specific phonological impairments. However, recent evidence is consistent with the possibility that phonological impairments arise as symptoms of an underlying dysfunction of procedural learning. The nature of the link between impaired procedural learning and phonological dysfunction is unresolved. Motivated by the observation that speech processing involves the acquisition of procedural category knowledge, the present study investigates the possibility that procedural learning impairment may affect phonological processing by interfering with the typical course of phonetic category learning. The present study tests this hypothesis while controlling for linguistic experience and possible speech-specific deficits by comparing auditory category learning across artificial, nonlinguistic sounds among dyslexic adults and matched controls in a specialized first-person shooter videogame that has been shown to engage procedural learning. Nonspeech auditory category learning was assessed online via within-game measures and also with a post-training task involving overt categorization of familiar and novel sound exemplars. Each measure reveals that dyslexic participants do not acquire procedural category knowledge as effectively as age- and cognitive-ability matched controls. This difference cannot be explained by differences in perceptual acuity for the sounds. Moreover, poor nonspeech category learning is associated with slower phonological processing. Whereas phonological processing impairments have been emphasized as the cause of dyslexia, the current results suggest that impaired auditory category learning, general in nature and not specific to speech signals, could contribute to phonological deficits in dyslexia with subsequent negative effects on language acquisition and reading. Implications for the neuro-cognitive mechanisms of developmental dyslexia are discussed.
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Affiliation(s)
- Yafit Gabay
- Carnegie Mellon University, Department of Psychology, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA, USA.
| | - Lori L Holt
- Carnegie Mellon University, Department of Psychology, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, Pittsburgh, PA, USA
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Lee YS, Peelle JE, Kraemer D, Lloyd S, Granger R. Multivariate sensitivity to voice during auditory categorization. J Neurophysiol 2015; 114:1819-26. [PMID: 26245316 DOI: 10.1152/jn.00407.2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 07/31/2015] [Indexed: 11/22/2022] Open
Abstract
Past neuroimaging studies have documented discrete regions of human temporal cortex that are more strongly activated by conspecific voice sounds than by nonvoice sounds. However, the mechanisms underlying this voice sensitivity remain unclear. In the present functional MRI study, we took a novel approach to examining voice sensitivity, in which we applied a signal detection paradigm to the assessment of multivariate pattern classification among several living and nonliving categories of auditory stimuli. Within this framework, voice sensitivity can be interpreted as a distinct neural representation of brain activity that correctly distinguishes human vocalizations from other auditory object categories. Across a series of auditory categorization tests, we found that bilateral superior and middle temporal cortex consistently exhibited robust sensitivity to human vocal sounds. Although the strongest categorization was in distinguishing human voice from other categories, subsets of these regions were also able to distinguish reliably between nonhuman categories, suggesting a general role in auditory object categorization. Our findings complement the current evidence of cortical sensitivity to human vocal sounds by revealing that the greatest sensitivity during categorization tasks is devoted to distinguishing voice from nonvoice categories within human temporal cortex.
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Affiliation(s)
- Yune Sang Lee
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire;
| | - Jonathan E Peelle
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, Missouri; and
| | - David Kraemer
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, Missouri; and Department of Education, Dartmouth College, Hanover, New Hampshire
| | - Samuel Lloyd
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire
| | - Richard Granger
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire
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29
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Abstract
Language learning requires that listeners discover acoustically variable functional units like phonetic categories and words from an unfamiliar, continuous acoustic stream. Although many category learning studies have examined how listeners learn to generalize across the acoustic variability inherent in the signals that convey the functional units of language, these studies have tended to focus upon category learning across isolated sound exemplars. However, continuous input presents many additional learning challenges that may impact category learning. Listeners may not know the timescale of the functional unit, its relative position in the continuous input, or its relationship to other evolving input regularities. Moving laboratory-based studies of isolated category exemplars toward more natural input is important to modeling language learning, but very little is known about how listeners discover categories embedded in continuous sound. In 3 experiments, adult participants heard acoustically variable sound category instances embedded in acoustically variable and unfamiliar sound streams within a video game task. This task was inherently rich in multisensory regularities with the to-be-learned categories and likely to engage procedural learning without requiring explicit categorization, segmentation, or even attention to the sounds. After 100 min of game play, participants categorized familiar sound streams in which target words were embedded and generalized this learning to novel streams as well as isolated instances of the target words. The findings demonstrate that even without a priori knowledge, listeners can discover input regularities that have the best predictive control over the environment for both non-native speech and nonspeech signals, emphasizing the generality of the learning.
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Affiliation(s)
- Sung-Joo Lim
- Department of Psychology, Carnegie Mellon University
| | | | - Lori L Holt
- Department of Psychology, Carnegie Mellon University
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30
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Evans S, Davis MH. Hierarchical Organization of Auditory and Motor Representations in Speech Perception: Evidence from Searchlight Similarity Analysis. Cereb Cortex 2015; 25:4772-88. [PMID: 26157026 PMCID: PMC4635918 DOI: 10.1093/cercor/bhv136] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
How humans extract the identity of speech sounds from highly variable acoustic signals remains unclear. Here, we use searchlight representational similarity analysis (RSA) to localize and characterize neural representations of syllables at different levels of the hierarchically organized temporo-frontal pathways for speech perception. We asked participants to listen to spoken syllables that differed considerably in their surface acoustic form by changing speaker and degrading surface acoustics using noise-vocoding and sine wave synthesis while we recorded neural responses with functional magnetic resonance imaging. We found evidence for a graded hierarchy of abstraction across the brain. At the peak of the hierarchy, neural representations in somatomotor cortex encoded syllable identity but not surface acoustic form, at the base of the hierarchy, primary auditory cortex showed the reverse. In contrast, bilateral temporal cortex exhibited an intermediate response, encoding both syllable identity and the surface acoustic form of speech. Regions of somatomotor cortex associated with encoding syllable identity in perception were also engaged when producing the same syllables in a separate session. These findings are consistent with a hierarchical account of how variable acoustic signals are transformed into abstract representations of the identity of speech sounds.
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Affiliation(s)
- Samuel Evans
- MRC Cognition and Brain Sciences Unit, Cambridge CB2 7EF, UK Institute of Cognitive Neuroscience, University College London, WC1 3AR, UK
| | - Matthew H Davis
- MRC Cognition and Brain Sciences Unit, Cambridge CB2 7EF, UK
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31
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Gabay Y, Dick FK, Zevin JD, Holt LL. Incidental auditory category learning. J Exp Psychol Hum Percept Perform 2015; 41:1124-38. [PMID: 26010588 DOI: 10.1037/xhp0000073] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Very little is known about how auditory categories are learned incidentally, without instructions to search for category-diagnostic dimensions, overt category decisions, or experimenter-provided feedback. This is an important gap because learning in the natural environment does not arise from explicit feedback and there is evidence that the learning systems engaged by traditional tasks are distinct from those recruited by incidental category learning. We examined incidental auditory category learning with a novel paradigm, the Systematic Multimodal Associations Reaction Time (SMART) task, in which participants rapidly detect and report the appearance of a visual target in 1 of 4 possible screen locations. Although the overt task is rapid visual detection, a brief sequence of sounds precedes each visual target. These sounds are drawn from 1 of 4 distinct sound categories that predict the location of the upcoming visual target. These many-to-one auditory-to-visuomotor correspondences support incidental auditory category learning. Participants incidentally learn categories of complex acoustic exemplars and generalize this learning to novel exemplars and tasks. Further, learning is facilitated when category exemplar variability is more tightly coupled to the visuomotor associations than when the same stimulus variability is experienced across trials. We relate these findings to phonetic category learning.
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Affiliation(s)
| | - Frederic K Dick
- Department of Psychological Sciences, Birkbeck College, University of London
| | - Jason D Zevin
- Department of Psychology, University of Southern California
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32
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Myers EB. Emergence of category-level sensitivities in non-native speech sound learning. Front Neurosci 2014; 8:238. [PMID: 25152708 PMCID: PMC4125857 DOI: 10.3389/fnins.2014.00238] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 07/20/2014] [Indexed: 11/23/2022] Open
Abstract
Over the course of development, speech sounds that are contrastive in one's native language tend to become perceived categorically: that is, listeners are unaware of variation within phonetic categories while showing excellent sensitivity to speech sounds that span linguistically meaningful phonetic category boundaries. The end stage of this developmental process is that the perceptual systems that handle acoustic-phonetic information show special tuning to native language contrasts, and as such, category-level information appears to be present at even fairly low levels of the neural processing stream. Research on adults acquiring non-native speech categories offers an avenue for investigating the interplay of category-level information and perceptual sensitivities to these sounds as speech categories emerge. In particular, one can observe the neural changes that unfold as listeners learn not only to perceive acoustic distinctions that mark non-native speech sound contrasts, but also to map these distinctions onto category-level representations. An emergent literature on the neural basis of novel and non-native speech sound learning offers new insight into this question. In this review, I will examine this literature in order to answer two key questions. First, where in the neural pathway does sensitivity to category-level phonetic information first emerge over the trajectory of speech sound learning? Second, how do frontal and temporal brain areas work in concert over the course of non-native speech sound learning? Finally, in the context of this literature I will describe a model of speech sound learning in which rapidly-adapting access to categorical information in the frontal lobes modulates the sensitivity of stable, slowly-adapting responses in the temporal lobes.
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Affiliation(s)
- Emily B Myers
- Department of Speech, Language, and Hearing Sciences, University of Connecticut Storrs, CT, USA ; Department of Psychology, University of Connecticut Storrs, CT, USA ; Haskins Laboratories New Haven, CT, USA
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33
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Lim SJ, Fiez JA, Holt LL. How may the basal ganglia contribute to auditory categorization and speech perception? Front Neurosci 2014; 8:230. [PMID: 25136291 PMCID: PMC4117994 DOI: 10.3389/fnins.2014.00230] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 07/13/2014] [Indexed: 02/01/2023] Open
Abstract
Listeners must accomplish two complementary perceptual feats in extracting a message from speech. They must discriminate linguistically-relevant acoustic variability and generalize across irrelevant variability. Said another way, they must categorize speech. Since the mapping of acoustic variability is language-specific, these categories must be learned from experience. Thus, understanding how, in general, the auditory system acquires and represents categories can inform us about the toolbox of mechanisms available to speech perception. This perspective invites consideration of findings from cognitive neuroscience literatures outside of the speech domain as a means of constraining models of speech perception. Although neurobiological models of speech perception have mainly focused on cerebral cortex, research outside the speech domain is consistent with the possibility of significant subcortical contributions in category learning. Here, we review the functional role of one such structure, the basal ganglia. We examine research from animal electrophysiology, human neuroimaging, and behavior to consider characteristics of basal ganglia processing that may be advantageous for speech category learning. We also present emerging evidence for a direct role for basal ganglia in learning auditory categories in a complex, naturalistic task intended to model the incidental manner in which speech categories are acquired. To conclude, we highlight new research questions that arise in incorporating the broader neuroscience research literature in modeling speech perception, and suggest how understanding contributions of the basal ganglia can inform attempts to optimize training protocols for learning non-native speech categories in adulthood.
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Affiliation(s)
- Sung-Joo Lim
- Department of Psychology, Carnegie Mellon University Pittsburgh, PA, USA ; Department of Neuroscience, Center for the Neural Basis of Cognition, University of Pittsburgh Pittsburgh, PA, USA
| | - Julie A Fiez
- Department of Neuroscience, Center for the Neural Basis of Cognition, University of Pittsburgh Pittsburgh, PA, USA ; Department of Neuroscience, Center for Neuroscience, University of Pittsburgh Pittsburgh, PA, USA ; Department of Psychology, University of Pittsburgh Pittsburgh, PA, USA
| | - Lori L Holt
- Department of Psychology, Carnegie Mellon University Pittsburgh, PA, USA ; Department of Neuroscience, Center for the Neural Basis of Cognition, University of Pittsburgh Pittsburgh, PA, USA ; Department of Neuroscience, Center for Neuroscience, University of Pittsburgh Pittsburgh, PA, USA
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34
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Molholm S, Mercier MR, Liebenthal E, Schwartz TH, Ritter W, Foxe JJ, De Sanctis P. Mapping phonemic processing zones along human perisylvian cortex: an electro-corticographic investigation. Brain Struct Funct 2014; 219:1369-83. [PMID: 23708059 PMCID: PMC4414312 DOI: 10.1007/s00429-013-0574-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 05/03/2013] [Indexed: 11/25/2022]
Abstract
The auditory system is organized such that progressively more complex features are represented across successive cortical hierarchical stages. Just when and where the processing of phonemes, fundamental elements of the speech signal, is achieved in this hierarchy remains a matter of vigorous debate. Non-invasive measures of phonemic representation have been somewhat equivocal. While some studies point to a primary role for middle/anterior regions of the superior temporal gyrus (STG), others implicate the posterior STG. Differences in stimulation, task and inter-individual anatomical/functional variability may account for these discrepant findings. Here, we sought to clarify this issue by mapping phonemic representation across left perisylvian cortex, taking advantage of the excellent sampling density afforded by intracranial recordings in humans. We asked whether one or both major divisions of the STG were sensitive to phonemic transitions. The high signal-to-noise characteristics of direct intracranial recordings allowed for analysis at the individual participant level, circumventing issues of inter-individual anatomic and functional variability that may have obscured previous findings at the group level of analysis. The mismatch negativity (MMN), an electrophysiological response elicited by changes in repetitive streams of stimulation, served as our primary dependent measure. Oddball configurations of pairs of phonemes, spectro-temporally matched non-phonemes, and simple tones were presented. The loci of the MMN clearly differed as a function of stimulus type. Phoneme representation was most robust over middle/anterior STG/STS, but was also observed over posterior STG/SMG. These data point to multiple phonemic processing zones along perisylvian cortex, both anterior and posterior to primary auditory cortex. This finding is considered within the context of a dual stream model of auditory processing in which functionally distinct ventral and dorsal auditory processing pathways may be engaged by speech stimuli.
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Affiliation(s)
- Sophie Molholm
- The Sheryl and Daniel R. Tishman Cognitive Neurophysiology Laboratory, Departments of Pediatrics and Neuroscience, Children's Evaluation and Rehabilitation Center (CERC), Albert Einstein College of Medicine, Van Etten Building-Wing 1C, 1225 Morris Park Avenue, Bronx, NY, 10461, USA,
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35
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Krishnan S, Leech R, Mercure E, Lloyd-Fox S, Dick F. Convergent and Divergent fMRI Responses in Children and Adults to Increasing Language Production Demands. Cereb Cortex 2014; 25:3261-77. [PMID: 24907249 PMCID: PMC4585486 DOI: 10.1093/cercor/bhu120] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In adults, patterns of neural activation associated with perhaps the most basic language skill—overt object naming—are extensively modulated by the psycholinguistic and visual complexity of the stimuli. Do children's brains react similarly when confronted with increasing processing demands, or they solve this problem in a different way? Here we scanned 37 children aged 7–13 and 19 young adults who performed a well-normed picture-naming task with 3 levels of difficulty. While neural organization for naming was largely similar in childhood and adulthood, adults had greater activation in all naming conditions over inferior temporal gyri and superior temporal gyri/supramarginal gyri. Manipulating naming complexity affected adults and children quite differently: neural activation, especially over the dorsolateral prefrontal cortex, showed complexity-dependent increases in adults, but complexity-dependent decreases in children. These represent fundamentally different responses to the linguistic and conceptual challenges of a simple naming task that makes no demands on literacy or metalinguistics. We discuss how these neural differences might result from different cognitive strategies used by adults and children during lexical retrieval/production as well as developmental changes in brain structure and functional connectivity.
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Affiliation(s)
- Saloni Krishnan
- Birkbeck-UCL Centre for NeuroImaging, London, UK Centre for Brain and Cognitive Development, Birkbeck, University of London, London, UK
| | - Robert Leech
- Department of Neurosciences and Mental Health, Imperial College London, London, UK
| | | | - Sarah Lloyd-Fox
- Centre for Brain and Cognitive Development, Birkbeck, University of London, London, UK
| | - Frederic Dick
- Birkbeck-UCL Centre for NeuroImaging, London, UK Centre for Brain and Cognitive Development, Birkbeck, University of London, London, UK
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36
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Ley A, Vroomen J, Formisano E. How learning to abstract shapes neural sound representations. Front Neurosci 2014; 8:132. [PMID: 24917783 PMCID: PMC4043152 DOI: 10.3389/fnins.2014.00132] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 05/14/2014] [Indexed: 12/04/2022] Open
Abstract
The transformation of acoustic signals into abstract perceptual representations is the essence of the efficient and goal-directed neural processing of sounds in complex natural environments. While the human and animal auditory system is perfectly equipped to process the spectrotemporal sound features, adequate sound identification and categorization require neural sound representations that are invariant to irrelevant stimulus parameters. Crucially, what is relevant and irrelevant is not necessarily intrinsic to the physical stimulus structure but needs to be learned over time, often through integration of information from other senses. This review discusses the main principles underlying categorical sound perception with a special focus on the role of learning and neural plasticity. We examine the role of different neural structures along the auditory processing pathway in the formation of abstract sound representations with respect to hierarchical as well as dynamic and distributed processing models. Whereas most fMRI studies on categorical sound processing employed speech sounds, the emphasis of the current review lies on the contribution of empirical studies using natural or artificial sounds that enable separating acoustic and perceptual processing levels and avoid interference with existing category representations. Finally, we discuss the opportunities of modern analyses techniques such as multivariate pattern analysis (MVPA) in studying categorical sound representations. With their increased sensitivity to distributed activation changes—even in absence of changes in overall signal level—these analyses techniques provide a promising tool to reveal the neural underpinnings of perceptually invariant sound representations.
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Affiliation(s)
- Anke Ley
- Department of Medical Psychology and Neuropsychology, Tilburg School of Social and Behavioral Sciences, Tilburg University Tilburg, Netherlands ; Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands
| | - Jean Vroomen
- Department of Medical Psychology and Neuropsychology, Tilburg School of Social and Behavioral Sciences, Tilburg University Tilburg, Netherlands
| | - Elia Formisano
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University Maastricht, Netherlands
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37
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Abstract
The mammalian auditory cortex integrates spectral and temporal acoustic features to support the perception of complex sounds, including conspecific vocalizations. Here we investigate coding of vocal stimuli in different subfields in macaque auditory cortex. We simultaneously measured auditory evoked potentials over a large swath of primary and higher order auditory cortex along the supratemporal plane in three animals chronically using high-density microelectrocorticographic arrays. To evaluate the capacity of neural activity to discriminate individual stimuli in these high-dimensional datasets, we applied a regularized multivariate classifier to evoked potentials to conspecific vocalizations. We found a gradual decrease in the level of overall classification performance along the caudal to rostral axis. Furthermore, the performance in the caudal sectors was similar across individual stimuli, whereas the performance in the rostral sectors significantly differed for different stimuli. Moreover, the information about vocalizations in the caudal sectors was similar to the information about synthetic stimuli that contained only the spectral or temporal features of the original vocalizations. In the rostral sectors, however, the classification for vocalizations was significantly better than that for the synthetic stimuli, suggesting that conjoined spectral and temporal features were necessary to explain differential coding of vocalizations in the rostral areas. We also found that this coding in the rostral sector was carried primarily in the theta frequency band of the response. These findings illustrate a progression in neural coding of conspecific vocalizations along the ventral auditory pathway.
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38
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Forbes A, Villegas J, Almryde KR, Plante E. A stereoscopic system for viewing the temporal evolution of brain activity clusters in response to linguistic stimuli. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2014; 9011:90110I. [PMID: 25075268 DOI: 10.1117/12.2042200] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In this paper, we present a novel application, 3D+Time Brain View, for the stereoscopic visualization of functional Magnetic Resonance Imaging (fMRI) data gathered from participants exposed to unfamiliar spoken languages. An analysis technique based on Independent Component Analysis (ICA) is used to identify statistically significant clusters of brain activity and their changes over time during different testing sessions. That is, our system illustrates the temporal evolution of participants' brain activity as they are introduced to a foreign language through displaying these clusters as they change over time. The raw fMRI data is presented as a stereoscopic pair in an immersive environment utilizing passive stereo rendering. The clusters are presented using a ray casting technique for volume rendering. Our system incorporates the temporal information and the results of the ICA into the stereoscopic 3D rendering, making it easier for domain experts to explore and analyze the data.
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Affiliation(s)
- Angus Forbes
- School of Information: Science, Technology, and Arts, University of Arizona
| | - Javier Villegas
- School of Information: Science, Technology, and Arts, University of Arizona
| | - Kyle R Almryde
- School of Information: Science, Technology, and Arts, University of Arizona ; Department of Speech, Language, and Hearing Sciences, The University of Arizona
| | - Elena Plante
- Department of Speech, Language, and Hearing Sciences, The University of Arizona
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39
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Klein ME, Zatorre RJ. Representations of Invariant Musical Categories Are Decodable by Pattern Analysis of Locally Distributed BOLD Responses in Superior Temporal and Intraparietal Sulci. Cereb Cortex 2014; 25:1947-57. [PMID: 24488957 DOI: 10.1093/cercor/bhu003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In categorical perception (CP), continuous physical signals are mapped to discrete perceptual bins: mental categories not found in the physical world. CP has been demonstrated across multiple sensory modalities and, in audition, for certain over-learned speech and musical sounds. The neural basis of auditory CP, however, remains ambiguous, including its robustness in nonspeech processes and the relative roles of left/right hemispheres; primary/nonprimary cortices; and ventral/dorsal perceptual processing streams. Here, highly trained musicians listened to 2-tone musical intervals, which they perceive categorically while undergoing functional magnetic resonance imaging. Multivariate pattern analyses were performed after grouping sounds by interval quality (determined by frequency ratio between tones) or pitch height (perceived noncategorically, frequency ratios remain constant). Distributed activity patterns in spheres of voxels were used to determine sound sample identities. For intervals, significant decoding accuracy was observed in the right superior temporal and left intraparietal sulci, with smaller peaks observed homologously in contralateral hemispheres. For pitch height, no significant decoding accuracy was observed, consistent with the non-CP of this dimension. These results suggest that similar mechanisms are operative for nonspeech categories as for speech; espouse roles for 2 segregated processing streams; and support hierarchical processing models for CP.
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Affiliation(s)
- Mike E Klein
- Cognitive Neuroscience Unit, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada H3A 2B4 International Laboratory for Brain, Music and Sound Research, Montréal, Québec, Canada H3C 3J7
| | - Robert J Zatorre
- Cognitive Neuroscience Unit, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada H3A 2B4 International Laboratory for Brain, Music and Sound Research, Montréal, Québec, Canada H3C 3J7
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40
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Knowland VCP, Mercure E, Karmiloff-Smith A, Dick F, Thomas MSC. Audio-visual speech perception: a developmental ERP investigation. Dev Sci 2014; 17:110-24. [PMID: 24176002 PMCID: PMC3995015 DOI: 10.1111/desc.12098] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 05/14/2013] [Indexed: 11/29/2022]
Abstract
Being able to see a talking face confers a considerable advantage for speech perception in adulthood. However, behavioural data currently suggest that children fail to make full use of these available visual speech cues until age 8 or 9. This is particularly surprising given the potential utility of multiple informational cues during language learning. We therefore explored this at the neural level. The event-related potential (ERP) technique has been used to assess the mechanisms of audio-visual speech perception in adults, with visual cues reliably modulating auditory ERP responses to speech. Previous work has shown congruence-dependent shortening of auditory N1/P2 latency and congruence-independent attenuation of amplitude in the presence of auditory and visual speech signals, compared to auditory alone. The aim of this study was to chart the development of these well-established modulatory effects over mid-to-late childhood. Experiment 1 employed an adult sample to validate a child-friendly stimulus set and paradigm by replicating previously observed effects of N1/P2 amplitude and latency modulation by visual speech cues; it also revealed greater attenuation of component amplitude given incongruent audio-visual stimuli, pointing to a new interpretation of the amplitude modulation effect. Experiment 2 used the same paradigm to map cross-sectional developmental change in these ERP responses between 6 and 11 years of age. The effect of amplitude modulation by visual cues emerged over development, while the effect of latency modulation was stable over the child sample. These data suggest that auditory ERP modulation by visual speech represents separable underlying cognitive processes, some of which show earlier maturation than others over the course of development.
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Affiliation(s)
- Victoria CP Knowland
- School of Health Sciences, City UniversityLondon, UK
- Department of Psychological Sciences, Birkbeck CollegeLondon, UK
| | | | | | - Fred Dick
- Department of Psychological Sciences, Birkbeck CollegeLondon, UK
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41
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Talkington WJ, Taglialatela JP, Lewis JW. Using naturalistic utterances to investigate vocal communication processing and development in human and non-human primates. Hear Res 2013; 305:74-85. [PMID: 23994296 PMCID: PMC3839530 DOI: 10.1016/j.heares.2013.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 08/07/2013] [Accepted: 08/19/2013] [Indexed: 11/16/2022]
Abstract
Humans and several non-human primates possess cortical regions that are most sensitive to vocalizations produced by their own kind (conspecifics). However, the use of speech and other broadly defined categories of behaviorally relevant natural sounds has led to many discrepancies regarding where voice-sensitivity occurs, and more generally the identification of cortical networks, "proto-networks" or protolanguage networks, and pathways that may be sensitive or selective for certain aspects of vocalization processing. In this prospective review we examine different approaches for exploring vocal communication processing, including pathways that may be, or become, specialized for conspecific utterances. In particular, we address the use of naturally produced non-stereotypical vocalizations (mimicry of other animal calls) as another category of vocalization for use with human and non-human primate auditory systems. We focus this review on two main themes, including progress and future ideas for studying vocalization processing in great apes (chimpanzees) and in very early stages of human development, including infants and fetuses. Advancing our understanding of the fundamental principles that govern the evolution and early development of cortical pathways for processing non-verbal communication utterances is expected to lead to better diagnoses and early intervention strategies in children with communication disorders, improve rehabilitation of communication disorders resulting from brain injury, and develop new strategies for intelligent hearing aid and implant design that can better enhance speech signals in noisy environments. This article is part of a Special Issue entitled "Communication Sounds and the Brain: New Directions and Perspectives".
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Affiliation(s)
- William J. Talkington
- Department of Neurobiology & Anatomy, Sensory Neuroscience Research Center, and Center for Advanced Imaging, West Virginia University, Morgantown, WV26506, USA
| | - Jared P. Taglialatela
- Department of Biology and Physics, Kennesaw State University, Kennesaw, Georgia, USA
| | - James W. Lewis
- Department of Neurobiology & Anatomy, Sensory Neuroscience Research Center, and Center for Advanced Imaging, West Virginia University, Morgantown, WV26506, USA
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42
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Scott SK, McGettigan C. Do temporal processes underlie left hemisphere dominance in speech perception? BRAIN AND LANGUAGE 2013; 127:36-45. [PMID: 24125574 PMCID: PMC4083253 DOI: 10.1016/j.bandl.2013.07.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 07/18/2013] [Accepted: 07/22/2013] [Indexed: 05/27/2023]
Abstract
It is not unusual to find it stated as a fact that the left hemisphere is specialized for the processing of rapid, or temporal aspects of sound, and that the dominance of the left hemisphere in the perception of speech can be a consequence of this specialization. In this review we explore the history of this claim and assess the weight of this assumption. We will demonstrate that instead of a supposed sensitivity of the left temporal lobe for the acoustic properties of speech, it is the right temporal lobe which shows a marked preference for certain properties of sounds, for example longer durations, or variations in pitch. We finish by outlining some alternative factors that contribute to the left lateralization of speech perception.
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Affiliation(s)
- Sophie K Scott
- Institute for Cognitive Neuroscience, 17 Queen Square, London WC1N 3AR, UK.
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43
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Emberson LL, Liu R, Zevin JD. Is statistical learning constrained by lower level perceptual organization? Cognition 2013; 128:82-102. [PMID: 23618755 PMCID: PMC4020322 DOI: 10.1016/j.cognition.2012.12.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 11/15/2012] [Accepted: 12/21/2012] [Indexed: 11/19/2022]
Abstract
In order for statistical information to aid in complex developmental processes such as language acquisition, learning from higher-order statistics (e.g. across successive syllables in a speech stream to support segmentation) must be possible while perceptual abilities (e.g. speech categorization) are still developing. The current study examines how perceptual organization interacts with statistical learning. Adult participants were presented with multiple exemplars from novel, complex sound categories designed to reflect some of the spectral complexity and variability of speech. These categories were organized into sequential pairs and presented such that higher-order statistics, defined based on sound categories, could support stream segmentation. Perceptual similarity judgments and multi-dimensional scaling revealed that participants only perceived three perceptual clusters of sounds and thus did not distinguish the four experimenter-defined categories, creating a tension between lower level perceptual organization and higher-order statistical information. We examined whether the resulting pattern of learning is more consistent with statistical learning being "bottom-up," constrained by the lower levels of organization, or "top-down," such that higher-order statistical information of the stimulus stream takes priority over perceptual organization and perhaps influences perceptual organization. We consistently find evidence that learning is constrained by perceptual organization. Moreover, participants generalize their learning to novel sounds that occupy a similar perceptual space, suggesting that statistical learning occurs based on regions of or clusters in perceptual space. Overall, these results reveal a constraint on learning of sound sequences such that statistical information is determined based on lower level organization. These findings have important implications for the role of statistical learning in language acquisition.
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Affiliation(s)
- Lauren L Emberson
- Brain and Cognitive Sciences Department, University of Rochester, United States.
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44
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Poremba A, Bigelow J, Rossi B. Processing of communication sounds: contributions of learning, memory, and experience. Hear Res 2013; 305:31-44. [PMID: 23792078 DOI: 10.1016/j.heares.2013.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/09/2013] [Accepted: 06/10/2013] [Indexed: 11/17/2022]
Abstract
Abundant evidence from both field and lab studies has established that conspecific vocalizations (CVs) are of critical ecological significance for a wide variety of species, including humans, non-human primates, rodents, and other mammals and birds. Correspondingly, a number of experiments have demonstrated behavioral processing advantages for CVs, such as in discrimination and memory tasks. Further, a wide range of experiments have described brain regions in many species that appear to be specialized for processing CVs. For example, several neural regions have been described in both mammals and birds wherein greater neural responses are elicited by CVs than by comparison stimuli such as heterospecific vocalizations, nonvocal complex sounds, and artificial stimuli. These observations raise the question of whether these regions reflect domain-specific neural mechanisms dedicated to processing CVs, or alternatively, if these regions reflect domain-general neural mechanisms for representing complex sounds of learned significance. Inasmuch as CVs can be viewed as complex combinations of basic spectrotemporal features, the plausibility of the latter position is supported by a large body of literature describing modulated cortical and subcortical representation of a variety of acoustic features that have been experimentally associated with stimuli of natural behavioral significance (such as food rewards). Herein, we review a relatively small body of existing literature describing the roles of experience, learning, and memory in the emergence of species-typical neural representations of CVs and auditory system plasticity. In both songbirds and mammals, manipulations of auditory experience as well as specific learning paradigms are shown to modulate neural responses evoked by CVs, either in terms of overall firing rate or temporal firing patterns. In some cases, CV-sensitive neural regions gradually acquire representation of non-CV stimuli with which subjects have training and experience. These results parallel literature in humans describing modulation of responses in face-sensitive neural regions through learning and experience. Thus, although many questions remain, the available evidence is consistent with the notion that CVs may acquire distinct neural representation through domain-general mechanisms for representing complex auditory objects that are of learned importance to the animal. This article is part of a Special Issue entitled "Communication Sounds and the Brain: New Directions and Perspectives".
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Affiliation(s)
- Amy Poremba
- University of Iowa, Dept. of Psychology, Div. Behavioral & Cognitive Neuroscience, E11 SSH, Iowa City, IA 52242, USA; University of Iowa, Neuroscience Program, Iowa City, IA 52242, USA.
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Mottron L, Bouvet L, Bonnel A, Samson F, Burack JA, Dawson M, Heaton P. Veridical mapping in the development of exceptional autistic abilities. Neurosci Biobehav Rev 2013; 37:209-28. [DOI: 10.1016/j.neubiorev.2012.11.016] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 11/22/2012] [Accepted: 11/23/2012] [Indexed: 10/27/2022]
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Learning of new sound categories shapes neural response patterns in human auditory cortex. J Neurosci 2012; 32:13273-80. [PMID: 22993443 DOI: 10.1523/jneurosci.0584-12.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The formation of new sound categories is fundamental to everyday goal-directed behavior. Categorization requires the abstraction of discrete classes from continuous physical features as required by context and task. Electrophysiology in animals has shown that learning to categorize novel sounds alters their spatiotemporal neural representation at the level of early auditory cortex. However, functional magnetic resonance imaging (fMRI) studies so far did not yield insight into the effects of category learning on sound representations in human auditory cortex. This may be due to the use of overlearned speech-like categories and fMRI subtraction paradigms, leading to insufficient sensitivity to distinguish the responses to learning-induced, novel sound categories. Here, we used fMRI pattern analysis to investigate changes in human auditory cortical response patterns induced by category learning. We created complex novel sound categories and analyzed distributed activation patterns during passive listening to a sound continuum before and after category learning. We show that only after training, sound categories could be successfully decoded from early auditory areas and that learning-induced pattern changes were specific to the category-distinctive sound feature (i.e., pitch). Notably, the similarity between fMRI response patterns for the sound continuum mirrored the sigmoid shape of the behavioral category identification function. Our results indicate that perceptual representations of novel sound categories emerge from neural changes at early levels of the human auditory processing hierarchy.
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Abstract
Numerous species possess cortical regions that are most sensitive to vocalizations produced by their own kind (conspecifics). In humans, the superior temporal sulci (STSs) putatively represent homologous voice-sensitive areas of cortex. However, superior temporal sulcus (STS) regions have recently been reported to represent auditory experience or "expertise" in general rather than showing exclusive sensitivity to human vocalizations per se. Using functional magnetic resonance imaging and a unique non-stereotypical category of complex human non-verbal vocalizations-human-mimicked versions of animal vocalizations-we found a cortical hierarchy in humans optimized for processing meaningful conspecific utterances. This left-lateralized hierarchy originated near primary auditory cortices and progressed into traditional speech-sensitive areas. Our results suggest that the cortical regions supporting vocalization perception are initially organized by sensitivity to the human vocal tract in stages before the STS. Additionally, these findings have implications for the developmental time course of conspecific vocalization processing in humans as well as its evolutionary origins.
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Myers EB, Swan K. Effects of category learning on neural sensitivity to non-native phonetic categories. J Cogn Neurosci 2012; 24:1695-708. [PMID: 22621261 DOI: 10.1162/jocn_a_00243] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Categorical perception, an increased sensitivity to between- compared with within-category contrasts, is a stable property of native speech perception that emerges as language matures. Although recent research suggests that categorical responses to speech sounds can be found in left prefrontal as well as temporo-parietal areas, it is unclear how the neural system develops heightened sensitivity to between-category contrasts. In the current study, two groups of adult participants were trained to categorize speech sounds taken from a dental/retroflex/velar continuum according to two different boundary locations. Behavioral results suggest that for successful learners, categorization training led to increased discrimination accuracy for between-category contrasts with no concomitant increase for within-category contrasts. Neural responses to the learned category schemes were measured using a short-interval habituation design during fMRI scanning. Whereas both inferior frontal and temporal regions showed sensitivity to phonetic contrasts sampled from the continuum, only the bilateral middle frontal gyri exhibited a pattern consistent with encoding of the learned category scheme. Taken together, these results support a view in which top-down information about category membership may reshape perceptual sensitivities via attention or executive mechanisms in the frontal lobes.
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Affiliation(s)
- Emily B Myers
- Department of Communication Sciences, University of Connecticut, 850 Bolton Rd., Storrs, CT 06269, USA.
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Price CJ. A review and synthesis of the first 20 years of PET and fMRI studies of heard speech, spoken language and reading. Neuroimage 2012; 62:816-47. [PMID: 22584224 PMCID: PMC3398395 DOI: 10.1016/j.neuroimage.2012.04.062] [Citation(s) in RCA: 1298] [Impact Index Per Article: 108.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 04/25/2012] [Accepted: 04/30/2012] [Indexed: 01/17/2023] Open
Abstract
The anatomy of language has been investigated with PET or fMRI for more than 20 years. Here I attempt to provide an overview of the brain areas associated with heard speech, speech production and reading. The conclusions of many hundreds of studies were considered, grouped according to the type of processing, and reported in the order that they were published. Many findings have been replicated time and time again leading to some consistent and undisputable conclusions. These are summarised in an anatomical model that indicates the location of the language areas and the most consistent functions that have been assigned to them. The implications for cognitive models of language processing are also considered. In particular, a distinction can be made between processes that are localized to specific structures (e.g. sensory and motor processing) and processes where specialisation arises in the distributed pattern of activation over many different areas that each participate in multiple functions. For example, phonological processing of heard speech is supported by the functional integration of auditory processing and articulation; and orthographic processing is supported by the functional integration of visual processing, articulation and semantics. Future studies will undoubtedly be able to improve the spatial precision with which functional regions can be dissociated but the greatest challenge will be to understand how different brain regions interact with one another in their attempts to comprehend and produce language.
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Affiliation(s)
- Cathy J Price
- Wellcome Trust Centre for Neuroimaging, UCL, London WC1N 3BG, UK.
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Lewis JW, Talkington WJ, Tallaksen KC, Frum CA. Auditory object salience: human cortical processing of non-biological action sounds and their acoustic signal attributes. Front Syst Neurosci 2012; 6:27. [PMID: 22582038 PMCID: PMC3348722 DOI: 10.3389/fnsys.2012.00027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 04/01/2012] [Indexed: 11/24/2022] Open
Abstract
Whether viewed or heard, an object in action can be segmented as a distinct salient event based on a number of different sensory cues. In the visual system, several low-level attributes of an image are processed along parallel hierarchies, involving intermediate stages wherein gross-level object form and/or motion features are extracted prior to stages that show greater specificity for different object categories (e.g., people, buildings, or tools). In the auditory system, though relying on a rather different set of low-level signal attributes, meaningful real-world acoustic events and “auditory objects” can also be readily distinguished from background scenes. However, the nature of the acoustic signal attributes or gross-level perceptual features that may be explicitly processed along intermediate cortical processing stages remain poorly understood. Examining mechanical and environmental action sounds, representing two distinct non-biological categories of action sources, we had participants assess the degree to which each sound was perceived as object-like versus scene-like. We re-analyzed data from two of our earlier functional magnetic resonance imaging (fMRI) task paradigms (Engel et al., 2009) and found that scene-like action sounds preferentially led to activation along several midline cortical structures, but with strong dependence on listening task demands. In contrast, bilateral foci along the superior temporal gyri (STG) showed parametrically increasing activation to action sounds rated as more “object-like,” independent of sound category or task demands. Moreover, these STG regions also showed parametric sensitivity to spectral structure variations (SSVs) of the action sounds—a quantitative measure of change in entropy of the acoustic signals over time—and the right STG additionally showed parametric sensitivity to measures of mean entropy and harmonic content of the environmental sounds. Analogous to the visual system, intermediate stages of the auditory system appear to process or extract a number of quantifiable low-order signal attributes that are characteristic of action events perceived as being object-like, representing stages that may begin to dissociate different perceptual dimensions and categories of every-day, real-world action sounds.
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Affiliation(s)
- James W Lewis
- Center for Neuroscience, West Virginia University, Morgantown WV, USA
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