1
|
MacLean J, Stirn J, Bidelman GM. Auditory-motor entrainment and listening experience shape the perceptual learning of concurrent speech. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.18.604167. [PMID: 39071391 PMCID: PMC11275804 DOI: 10.1101/2024.07.18.604167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Background Plasticity from auditory experience shapes the brain's encoding and perception of sound. Though prior research demonstrates that neural entrainment (i.e., brain-to-acoustic synchronization) aids speech perception, how long- and short-term plasticity influence entrainment to concurrent speech has not been investigated. Here, we explored neural entrainment mechanisms and the interplay between short- and long-term neuroplasticity for rapid auditory perceptual learning of concurrent speech sounds in young, normal-hearing musicians and nonmusicians. Method Participants learned to identify double-vowel mixtures during ∼45 min training sessions with concurrent high-density EEG recordings. We examined the degree to which brain responses entrained to the speech-stimulus train (∼9 Hz) to investigate whether entrainment to speech prior to behavioral decision predicted task performance. Source and directed functional connectivity analyses of the EEG probed whether behavior was driven by group differences auditory-motor coupling. Results Both musicians and nonmusicians showed rapid perceptual learning in accuracy with training. Interestingly, listeners' neural entrainment strength prior to target speech mixtures predicted behavioral identification performance; stronger neural synchronization was observed preceding incorrect compared to correct trial responses. We also found stark hemispheric biases in auditory-motor coupling during speech entrainment, with greater auditory-motor connectivity in the right compared to left hemisphere for musicians (R>L) but not in nonmusicians (R=L). Conclusions Our findings confirm stronger neuroacoustic synchronization and auditory-motor coupling during speech processing in musicians. Stronger neural entrainment to rapid stimulus trains preceding incorrect behavioral responses supports the notion that alpha-band (∼10 Hz) arousal/suppression in brain activity is an important modulator of trial-by-trial success in perceptual processing.
Collapse
|
2
|
MacLean J, Stirn J, Sisson A, Bidelman GM. Short- and long-term neuroplasticity interact during the perceptual learning of concurrent speech. Cereb Cortex 2024; 34:bhad543. [PMID: 38212291 PMCID: PMC10839853 DOI: 10.1093/cercor/bhad543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/13/2024] Open
Abstract
Plasticity from auditory experience shapes the brain's encoding and perception of sound. However, whether such long-term plasticity alters the trajectory of short-term plasticity during speech processing has yet to be investigated. Here, we explored the neural mechanisms and interplay between short- and long-term neuroplasticity for rapid auditory perceptual learning of concurrent speech sounds in young, normal-hearing musicians and nonmusicians. Participants learned to identify double-vowel mixtures during ~ 45 min training sessions recorded simultaneously with high-density electroencephalography (EEG). We analyzed frequency-following responses (FFRs) and event-related potentials (ERPs) to investigate neural correlates of learning at subcortical and cortical levels, respectively. Although both groups showed rapid perceptual learning, musicians showed faster behavioral decisions than nonmusicians overall. Learning-related changes were not apparent in brainstem FFRs. However, plasticity was highly evident in cortex, where ERPs revealed unique hemispheric asymmetries between groups suggestive of different neural strategies (musicians: right hemisphere bias; nonmusicians: left hemisphere). Source reconstruction and the early (150-200 ms) time course of these effects localized learning-induced cortical plasticity to auditory-sensory brain areas. Our findings reinforce the domain-general benefits of musicianship but reveal that successful speech sound learning is driven by a critical interplay between long- and short-term mechanisms of auditory plasticity, which first emerge at a cortical level.
Collapse
Affiliation(s)
- Jessica MacLean
- Department of Speech, Language and Hearing Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
| | - Jack Stirn
- Department of Speech, Language and Hearing Sciences, Indiana University, Bloomington, IN, USA
| | - Alexandria Sisson
- Department of Speech, Language and Hearing Sciences, Indiana University, Bloomington, IN, USA
| | - Gavin M Bidelman
- Department of Speech, Language and Hearing Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Cognitive Science Program, Indiana University, Bloomington, IN, USA
| |
Collapse
|
3
|
Jelinek J, Johne M, Alam M, Krauss JK, Kral A, Schwabe K. Hearing loss in juvenile rats leads to excessive play fighting and hyperactivity, mild cognitive deficits and altered neuronal activity in the prefrontal cortex. CURRENT RESEARCH IN NEUROBIOLOGY 2024; 6:100124. [PMID: 38616957 PMCID: PMC11015060 DOI: 10.1016/j.crneur.2024.100124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 12/23/2023] [Accepted: 12/29/2023] [Indexed: 04/16/2024] Open
Abstract
Background In children, hearing loss has been associated with hyperactivity, disturbed social interaction, and risk of cognitive disturbances. Mechanistic explanations of these relations sometimes involve language. To investigate the effect of hearing loss on behavioral deficits in the absence of language, we tested the impact of hearing loss in juvenile rats on motor, social, and cognitive behavior and on physiology of prefrontal cortex. Methods Hearing loss was induced in juvenile (postnatal day 14) male Sprague-Dawley rats by intracochlear injection of neomycin under general anesthesia. Sham-operated and non-operated hearing rats served as controls. One week after surgery auditory brainstem response (ABR) measurements verified hearing loss or intact hearing in sham-operated and non-operated controls. All rats were then tested for locomotor activity (open field), coordination (Rotarod), and for social interaction during development in weeks 1, 2, 4, 8, 16, and 24 after surgery. From week 8 on, rats were trained and tested for spatial learning and memory (4-arm baited 8-arm radial maze test). In a final setting, neuronal activity was recorded in the medial prefrontal cortex (mPFC). Results In the open field deafened rats moved faster and covered more distance than sham-operated and non-operated controls from week 8 on (both p < 0.05). Deafened rats showed significantly more play fighting during development (p < 0.05), whereas other aspects of social interaction, such as following, were not affected. Learning of the radial maze test was not impaired in deafened rats (p > 0.05), but rats used less next-arm entries than other groups indicating impaired concept learning (p < 0.05). In the mPFC neuronal firing rate was reduced and enhanced irregular firing was observed. Moreover, oscillatory activity was altered, both within the mPFC and in coherence of mPFC with the somatosensory cortex (p < 0.05). Conclusions Hearing loss in juvenile rats leads to hyperactive behavior and pronounced play-fighting during development, suggesting a causal relationship between hearing loss and cognitive development. Altered neuronal activities in the mPFC after hearing loss support such effects on neuronal networks outside the central auditory system. This animal model provides evidence of developmental consequences of juvenile hearing loss on prefrontal cortex in absence of language as potential confounding factor.
Collapse
Affiliation(s)
- Jonas Jelinek
- Department of Neurosurgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Marie Johne
- Department of Neurosurgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
| | - Mesbah Alam
- Department of Neurosurgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Joachim K. Krauss
- Department of Neurosurgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Andrej Kral
- Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
- Institute of AudioNeuroTechnology, Hannover Medical School, Stadtfelddamm 34, 30625, Hanover, Germany
- Department of Experimental Otology of the ENT Clinics, Hannover Medical School, Stadtfelddamm 34, 30625, Hannover, Germany
| | - Kerstin Schwabe
- Department of Neurosurgery, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
- Cluster of Excellence Hearing4all, German Research Foundation, Hannover, Germany
| |
Collapse
|
4
|
MacLean J, Stirn J, Sisson A, Bidelman GM. Short- and long-term experience-dependent neuroplasticity interact during the perceptual learning of concurrent speech. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.26.559640. [PMID: 37808665 PMCID: PMC10557636 DOI: 10.1101/2023.09.26.559640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Plasticity from auditory experiences shapes brain encoding and perception of sound. However, whether such long-term plasticity alters the trajectory of short-term plasticity during speech processing has yet to be investigated. Here, we explored the neural mechanisms and interplay between short- and long-term neuroplasticity for rapid auditory perceptual learning of concurrent speech sounds in young, normal-hearing musicians and nonmusicians. Participants learned to identify double-vowel mixtures during ∼45 minute training sessions recorded simultaneously with high-density EEG. We analyzed frequency-following responses (FFRs) and event-related potentials (ERPs) to investigate neural correlates of learning at subcortical and cortical levels, respectively. While both groups showed rapid perceptual learning, musicians showed faster behavioral decisions than nonmusicians overall. Learning-related changes were not apparent in brainstem FFRs. However, plasticity was highly evident in cortex, where ERPs revealed unique hemispheric asymmetries between groups suggestive of different neural strategies (musicians: right hemisphere bias; nonmusicians: left hemisphere). Source reconstruction and the early (150-200 ms) time course of these effects localized learning-induced cortical plasticity to auditory-sensory brain areas. Our findings confirm domain-general benefits for musicianship but reveal successful speech sound learning is driven by a critical interplay between long- and short-term mechanisms of auditory plasticity that first emerge at a cortical level.
Collapse
|
5
|
Bidelman GM, Carter JA. Continuous dynamics in behavior reveal interactions between perceptual warping in categorization and speech-in-noise perception. Front Neurosci 2023; 17:1032369. [PMID: 36937676 PMCID: PMC10014819 DOI: 10.3389/fnins.2023.1032369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 02/14/2023] [Indexed: 03/05/2023] Open
Abstract
Introduction Spoken language comprehension requires listeners map continuous features of the speech signal to discrete category labels. Categories are however malleable to surrounding context and stimulus precedence; listeners' percept can dynamically shift depending on the sequencing of adjacent stimuli resulting in a warping of the heard phonetic category. Here, we investigated whether such perceptual warping-which amplify categorical hearing-might alter speech processing in noise-degraded listening scenarios. Methods We measured continuous dynamics in perception and category judgments of an acoustic-phonetic vowel gradient via mouse tracking. Tokens were presented in serial vs. random orders to induce more/less perceptual warping while listeners categorized continua in clean and noise conditions. Results Listeners' responses were faster and their mouse trajectories closer to the ultimate behavioral selection (marked visually on the screen) in serial vs. random order, suggesting increased perceptual attraction to category exemplars. Interestingly, order effects emerged earlier and persisted later in the trial time course when categorizing speech in noise. Discussion These data describe interactions between perceptual warping in categorization and speech-in-noise perception: warping strengthens the behavioral attraction to relevant speech categories, making listeners more decisive (though not necessarily more accurate) in their decisions of both clean and noise-degraded speech.
Collapse
Affiliation(s)
- Gavin M. Bidelman
- Department of Speech, Language and Hearing Sciences, Indiana University, Bloomington, IN, United States
- Program in Neuroscience, Indiana University, Bloomington, IN, United States
| | - Jared A. Carter
- School of Communication Sciences and Disorders, University of Memphis, Memphis, TN, United States
- Hearing Sciences – Scottish Section, Division of Clinical Neuroscience, School of Medicine, University of Nottingham, Glasgow, United Kingdom
| |
Collapse
|
6
|
Xu N, Zhao B, Luo L, Zhang K, Shao X, Luan G, Wang Q, Hu W, Wang Q. Two stages of speech envelope tracking in human auditory cortex modulated by speech intelligibility. Cereb Cortex 2023; 33:2215-2228. [PMID: 35695785 DOI: 10.1093/cercor/bhac203] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
The envelope is essential for speech perception. Recent studies have shown that cortical activity can track the acoustic envelope. However, whether the tracking strength reflects the extent of speech intelligibility processing remains controversial. Here, using stereo-electroencephalogram technology, we directly recorded the activity in human auditory cortex while subjects listened to either natural or noise-vocoded speech. These 2 stimuli have approximately identical envelopes, but the noise-vocoded speech does not have speech intelligibility. According to the tracking lags, we revealed 2 stages of envelope tracking: an early high-γ (60-140 Hz) power stage that preferred the noise-vocoded speech and a late θ (4-8 Hz) phase stage that preferred the natural speech. Furthermore, the decoding performance of high-γ power was better in primary auditory cortex than in nonprimary auditory cortex, consistent with its short tracking delay, while θ phase showed better decoding performance in right auditory cortex. In addition, high-γ responses with sustained temporal profiles in nonprimary auditory cortex were dominant in both envelope tracking and decoding. In sum, we suggested a functional dissociation between high-γ power and θ phase: the former reflects fast and automatic processing of brief acoustic features, while the latter correlates to slow build-up processing facilitated by speech intelligibility.
Collapse
Affiliation(s)
- Na Xu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China.,National Clinical Research Center for Neurological Diseases, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China
| | - Baotian Zhao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China
| | - Lu Luo
- School of Psychology, Beijing Sport University, No. 48 Xinxi Road, Haidian District, Beijing 100084, China
| | - Kai Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China
| | - Xiaoqiu Shao
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China
| | - Guoming Luan
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Sanbo Brain Hospital, Capital Medical University, No. 50 Yikesong Xiangshan Road, Haidian District, Beijing 100093, China.,Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, No.10 Xitoutiao, You An Men, Beijing 100069, China
| | - Qian Wang
- Beijing Key Laboratory of Epilepsy, Epilepsy Center, Sanbo Brain Hospital, Capital Medical University, No. 50 Yikesong Xiangshan Road, Haidian District, Beijing 100093, China.,School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, No.5 Yiheyuan Road, Haidian District, Beijing 100871, China.,IDG/McGovern Institute for Brain Research, Peking University, No.5 Yiheyuan Road, Haidian District, Beijing 100871, China
| | - Wenhan Hu
- Beijing Neurosurgical Institute, Capital Medical University, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China
| | - Qun Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China.,National Clinical Research Center for Neurological Diseases, No. 119 South Fourth Ring West Road, Fengtai District, Beijing 100070, China.,Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, No.10 Xitoutiao, You An Men, Beijing 100069, China
| |
Collapse
|
7
|
Zheng Y, Liu L, Li R, Wu Z, Chen L, Li J, Wu C, Kong L, Zhang C, Lei M, She S, Ning Y, Li L. Impaired interaural correlation processing in people with schizophrenia. Eur J Neurosci 2021; 54:6646-6662. [PMID: 34494695 DOI: 10.1111/ejn.15449] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 08/19/2021] [Accepted: 09/03/2021] [Indexed: 01/05/2023]
Abstract
Detection of transient changes in interaural correlation is based on the temporal precision of the central representations of acoustic signals. Whether schizophrenia impairs the temporal precision in the interaural correlation process is not clear. In both participants with schizophrenia and matched healthy-control participants, this study examined the detection of a break in interaural correlation (BIC, a change in interaural correlation from 1 to 0 and back to 1), including the longest interaural delay at which a BIC was just audible, representing the temporal extent of the primitive auditory memory (PAM). Moreover, BIC-induced electroencephalograms (EEGs) and the relationships between the early binaural psychoacoustic processing and higher cognitive functions, which were assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), were examined. The results showed that compared to healthy controls, participants with schizophrenia exhibited poorer BIC detection, PAM and RBANS score. Both the BIC-detection accuracy and the PAM extent were correlated with the RBANS score. Moreover, participants with schizophrenia showed weaker BIC-induced N1-P2 amplitude which was correlated with both theta-band power and inter-trial phase coherence. These results suggested that schizophrenia impairs the temporal precision of the central representations of acoustic signals, affecting both interaural correlation processing and higher-order cognitions.
Collapse
Affiliation(s)
- Yingjun Zheng
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Lei Liu
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Ruikeng Li
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Zhemeng Wu
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Liangjie Chen
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Juanhua Li
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Chao Wu
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Lingzhi Kong
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Changxin Zhang
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Ming Lei
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| | - Shenglin She
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Yuping Ning
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Liang Li
- School of Psychological and Cognitive Sciences, Key Laboratory on Machine Perception (Ministry of Education), Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing, China
| |
Collapse
|
8
|
Momtaz S, Moncrieff D, Bidelman GM. Dichotic listening deficits in amblyaudia are characterized by aberrant neural oscillations in auditory cortex. Clin Neurophysiol 2021; 132:2152-2162. [PMID: 34284251 DOI: 10.1016/j.clinph.2021.04.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 04/16/2021] [Accepted: 04/29/2021] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Children diagnosed with auditory processing disorder (APD) show deficits in processing complex sounds that are associated with difficulties in higher-order language, learning, cognitive, and communicative functions. Amblyaudia (AMB) is a subcategory of APD characterized by abnormally large ear asymmetries in dichotic listening tasks. METHODS Here, we examined frequency-specific neural oscillations and functional connectivity via high-density electroencephalography (EEG) in children with and without AMB during passive listening of nonspeech stimuli. RESULTS Time-frequency maps of these "brain rhythms" revealed stronger phase-locked beta-gamma (~35 Hz) oscillations in AMB participants within bilateral auditory cortex for sounds presented to the right ear, suggesting a hypersynchronization and imbalance of auditory neural activity. Brain-behavior correlations revealed neural asymmetries in cortical responses predicted the larger than normal right-ear advantage seen in participants with AMB. Additionally, we found weaker functional connectivity in the AMB group from right to left auditory cortex, despite their stronger neural responses overall. CONCLUSION Our results reveal abnormally large auditory sensory encoding and an imbalance in communication between cerebral hemispheres (ipsi- to -contralateral signaling) in AMB. SIGNIFICANCE These neurophysiological changes might lead to the functionally poorer behavioral capacity to integrate information between the two ears in children with AMB.
Collapse
Affiliation(s)
- Sara Momtaz
- School of Communication Sciences & Disorders, University of Memphis, Memphis, TN, USA.
| | - Deborah Moncrieff
- School of Communication Sciences & Disorders, University of Memphis, Memphis, TN, USA
| | - Gavin M Bidelman
- School of Communication Sciences & Disorders, University of Memphis, Memphis, TN, USA; Institute for Intelligent Systems, University of Memphis, Memphis, TN, USA; University of Tennessee Health Sciences Center, Department of Anatomy and Neurobiology, Memphis, TN, USA
| |
Collapse
|
9
|
Differential contributions of synaptic and intrinsic inhibitory currents to speech segmentation via flexible phase-locking in neural oscillators. PLoS Comput Biol 2021; 17:e1008783. [PMID: 33852573 PMCID: PMC8104450 DOI: 10.1371/journal.pcbi.1008783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/07/2021] [Accepted: 02/05/2021] [Indexed: 01/07/2023] Open
Abstract
Current hypotheses suggest that speech segmentation—the initial division and grouping of the speech stream into candidate phrases, syllables, and phonemes for further linguistic processing—is executed by a hierarchy of oscillators in auditory cortex. Theta (∼3-12 Hz) rhythms play a key role by phase-locking to recurring acoustic features marking syllable boundaries. Reliable synchronization to quasi-rhythmic inputs, whose variable frequency can dip below cortical theta frequencies (down to ∼1 Hz), requires “flexible” theta oscillators whose underlying neuronal mechanisms remain unknown. Using biophysical computational models, we found that the flexibility of phase-locking in neural oscillators depended on the types of hyperpolarizing currents that paced them. Simulated cortical theta oscillators flexibly phase-locked to slow inputs when these inputs caused both (i) spiking and (ii) the subsequent buildup of outward current sufficient to delay further spiking until the next input. The greatest flexibility in phase-locking arose from a synergistic interaction between intrinsic currents that was not replicated by synaptic currents at similar timescales. Flexibility in phase-locking enabled improved entrainment to speech input, optimal at mid-vocalic channels, which in turn supported syllabic-timescale segmentation through identification of vocalic nuclei. Our results suggest that synaptic and intrinsic inhibition contribute to frequency-restricted and -flexible phase-locking in neural oscillators, respectively. Their differential deployment may enable neural oscillators to play diverse roles, from reliable internal clocking to adaptive segmentation of quasi-regular sensory inputs like speech. Oscillatory activity in auditory cortex is believed to play an important role in auditory and speech processing. One suggested function of these rhythms is to divide the speech stream into candidate phonemes, syllables, words, and phrases, to be matched with learned linguistic templates. This requires brain rhythms to flexibly synchronize with regular acoustic features of the speech stream. How neuronal circuits implement this task remains unknown. In this study, we explored the contribution of inhibitory currents to flexible phase-locking in neuronal theta oscillators, believed to perform initial syllabic segmentation. We found that a combination of specific intrinsic inhibitory currents at multiple timescales, present in a large class of cortical neurons, enabled exceptionally flexible phase-locking, which could be used to precisely segment speech by identifying vowels at mid-syllable. This suggests that the cells exhibiting these currents are a key component in the brain’s auditory and speech processing architecture.
Collapse
|
10
|
Mahmud MS, Yeasin M, Bidelman GM. Speech categorization is better described by induced rather than evoked neural activity. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2021; 149:1644. [PMID: 33765780 PMCID: PMC8267855 DOI: 10.1121/10.0003572] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Categorical perception (CP) describes how the human brain categorizes speech despite inherent acoustic variability. We examined neural correlates of CP in both evoked and induced electroencephalogram (EEG) activity to evaluate which mode best describes the process of speech categorization. Listeners labeled sounds from a vowel gradient while we recorded their EEGs. Using a source reconstructed EEG, we used band-specific evoked and induced neural activity to build parameter optimized support vector machine models to assess how well listeners' speech categorization could be decoded via whole-brain and hemisphere-specific responses. We found whole-brain evoked β-band activity decoded prototypical from ambiguous speech sounds with ∼70% accuracy. However, induced γ-band oscillations showed better decoding of speech categories with ∼95% accuracy compared to evoked β-band activity (∼70% accuracy). Induced high frequency (γ-band) oscillations dominated CP decoding in the left hemisphere, whereas lower frequencies (θ-band) dominated the decoding in the right hemisphere. Moreover, feature selection identified 14 brain regions carrying induced activity and 22 regions of evoked activity that were most salient in describing category-level speech representations. Among the areas and neural regimes explored, induced γ-band modulations were most strongly associated with listeners' behavioral CP. The data suggest that the category-level organization of speech is dominated by relatively high frequency induced brain rhythms.
Collapse
Affiliation(s)
- Md Sultan Mahmud
- Department of Electrical and Computer Engineering, University of Memphis, 3815 Central Avenue, Memphis, Tennessee 38152, USA
| | - Mohammed Yeasin
- Department of Electrical and Computer Engineering, University of Memphis, 3815 Central Avenue, Memphis, Tennessee 38152, USA
| | - Gavin M Bidelman
- School of Communication Sciences and Disorders, University of Memphis, 4055 North Park Loop, Memphis, Tennessee 38152, USA
| |
Collapse
|
11
|
Yin Z, Wang Y, Dong M, Wang Y, Ren S, Liang J. Short-range and long-range neuronal oscillatory coupling in multiple frequency bands during face perception. Int J Psychophysiol 2020; 152:26-35. [PMID: 32277957 DOI: 10.1016/j.ijpsycho.2020.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 03/31/2020] [Accepted: 04/03/2020] [Indexed: 01/29/2023]
Abstract
Neuronal oscillatory activity has been considered to play a key role in face processing through its functional effect on information flow and exchange in human brain. Specifically, most neuronal oscillatory activity is measured in different rhythm based on the electrophysiological signal at single channel level. Although, the neuronal oscillatory coupling between neuronal assembles is associated with the information flow and exchange between brain regions, few studies focus on this type of neuronal oscillatory activity in face processing. In this study, the neuronal oscillatory coupling was investigated based on electroencephalographic (EEG) data of 20 participants, which were recorded when the participants were in a face/non-face perceptual task. The phase lag index (PLI) was used to assess the neuronal oscillatory coupling between brain regions in typical frequency bands. Enhanced short-range coupling was observed in theta (4-8 Hz) and alpha (8-12 Hz) band over the frontal region, in gamma1 (30-49 Hz) band over the left posterior and occipito-temporal regions, and in gamma2 (51-75 Hz) over the right temporal region during face perception compared with non-face perception. Long-range coupling was increased in theta and gamma band over the right hemisphere during face perception. Moreover, increased long-range coupling was observed in alpha band over the left and right hemisphere respectively during face perception. The results suggested that frequency-specific neuronal oscillatory coupling within and between regions of frontal cortex and the ventral visual pathway played an important role in face perception, which might reflect underlying neural mechanism of face perception.
Collapse
Affiliation(s)
- Zhongliang Yin
- Engineering Research Center of Molecular and Neuro Imaging of Ministry of Education, School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China
| | - Ying Wang
- School of Electronic Engineering, Xidian University, Xi'an, Shaanxi 710071, China
| | - Minghao Dong
- Engineering Research Center of Molecular and Neuro Imaging of Ministry of Education, School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China
| | - Yubo Wang
- Engineering Research Center of Molecular and Neuro Imaging of Ministry of Education, School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China
| | - Shenghan Ren
- Engineering Research Center of Molecular and Neuro Imaging of Ministry of Education, School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China
| | - Jimin Liang
- School of Electronic Engineering, Xidian University, Xi'an, Shaanxi 710071, China.
| |
Collapse
|
12
|
Auditory-frontal Channeling in α and β Bands is Altered by Age-related Hearing Loss and Relates to Speech Perception in Noise. Neuroscience 2019; 423:18-28. [PMID: 31705894 DOI: 10.1016/j.neuroscience.2019.10.044] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/19/2019] [Accepted: 10/27/2019] [Indexed: 01/16/2023]
Abstract
Difficulty understanding speech-in-noise (SIN) is a pervasive problem faced by older adults particularly those with hearing loss. Previous studies have identified structural and functional changes in the brain that contribute to older adults' speech perception difficulties. Yet, many of these studies use neuroimaging techniques that evaluate only gross activation in isolated brain regions. Neural oscillations may provide further insight into the processes underlying SIN perception as well as the interaction between auditory cortex and prefrontal linguistic brain regions that mediate complex behaviors. We examined frequency-specific neural oscillations and functional connectivity of the EEG in older adults with and without hearing loss during an active SIN perception task. Brain-behavior correlations revealed listeners who were more resistant to the detrimental effects of noise also demonstrated greater modulation of α phase coherence between clean and noise-degraded speech, suggesting α desynchronization reflects release from inhibition and more flexible allocation of neural resources. Additionally, we found top-down β connectivity between prefrontal and auditory cortices strengthened with poorer hearing thresholds despite minimal behavioral differences. This is consistent with the proposal that linguistic brain areas may be recruited to compensate for impoverished auditory inputs through increased top-down predictions to assist SIN perception. Overall, these results emphasize the importance of top-down signaling in low-frequency brain rhythms that help compensate for hearing-related declines and facilitate efficient SIN processing.
Collapse
|
13
|
Yellamsetty A, Bidelman GM. Brainstem correlates of concurrent speech identification in adverse listening conditions. Brain Res 2019; 1714:182-192. [PMID: 30796895 DOI: 10.1016/j.brainres.2019.02.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/07/2019] [Accepted: 02/19/2019] [Indexed: 01/20/2023]
Abstract
When two voices compete, listeners can segregate and identify concurrent speech sounds using pitch (fundamental frequency, F0) and timbre (harmonic) cues. Speech perception is also hindered by the signal-to-noise ratio (SNR). How clear and degraded concurrent speech sounds are represented at early, pre-attentive stages of the auditory system is not well understood. To this end, we measured scalp-recorded frequency-following responses (FFR) from the EEG while human listeners heard two concurrently presented, steady-state (time-invariant) vowels whose F0 differed by zero or four semitones (ST) presented diotically in either clean (no noise) or noise-degraded (+5dB SNR) conditions. Listeners also performed a speeded double vowel identification task in which they were required to identify both vowels correctly. Behavioral results showed that speech identification accuracy increased with F0 differences between vowels, and this perceptual F0 benefit was larger for clean compared to noise degraded (+5dB SNR) stimuli. Neurophysiological data demonstrated more robust FFR F0 amplitudes for single compared to double vowels and considerably weaker responses in noise. F0 amplitudes showed speech-on-speech masking effects, along with a non-linear constructive interference at 0ST, and suppression effects at 4ST. Correlations showed that FFR F0 amplitudes failed to predict listeners' identification accuracy. In contrast, FFR F1 amplitudes were associated with faster reaction times, although this correlation was limited to noise conditions. The limited number of brain-behavior associations suggests subcortical activity mainly reflects exogenous processing rather than perceptual correlates of concurrent speech perception. Collectively, our results demonstrate that FFRs reflect pre-attentive coding of concurrent auditory stimuli that only weakly predict the success of identifying concurrent speech.
Collapse
Affiliation(s)
- Anusha Yellamsetty
- School of Communication Sciences & Disorders, University of Memphis, Memphis, TN, USA; Department of Communication Sciences & Disorders, University of South Florida, USA.
| | - Gavin M Bidelman
- School of Communication Sciences & Disorders, University of Memphis, Memphis, TN, USA; Institute for Intelligent Systems, University of Memphis, Memphis, TN, USA; University of Tennessee Health Sciences Center, Department of Anatomy and Neurobiology, Memphis, TN, USA.
| |
Collapse
|