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Rimmele, J. M.

Publications and source records attributed to Rimmele, J. M..

10 recordsLinked to original sources

Linguistic information compensates for age-related decline in attentional filtering

As we age, understanding speech in social situations imposes an increasingly difficult challenge to the auditory system. However, the attentional mechanisms underlying age-related speech comprehension difficulties in multitalker situations remain unclear. We collected EEG signals while 63 normal hearing participants from 19 to 71 years performed a speech comprehension task involving a multitalker paradigm at individually adjusted target-to-distractor ratios. Combining trial-resolved multivariate temporal response function modeling with detailed behavioral comprehension responses, we provide a window into lower-level impairments and higher-level compensatory mechanisms across the adult life span. Neuro-behavioral correlations on a trial-by-trial level provide direct evidence for increased distractor representation underlying reduced behavioral performance in late adulthood. This points towards increased distractibility as a potential mechanism underlying age-related speech comprehension deficits. Additionally, at the behavioral and neural levels, we show that older adults relied more on higher-level linguistic information. Finally, we show that an increased reliance on word-level linguistic information may compensate for increased distractor tracking and adaptively support comprehension performance across the adult life span. Specifically, we directly show that increased reliance on higher-level processing can offset age-related impairments in attentional filtering.

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Auditory-motor synchronization determines the use of predictions in music perception

When listening to music, our brain constantly generates predictions about the timing and pitch of upcoming sounds based on the structure of the music. Individual differences in the ability to make such rhythmic and melodic predictions shape music perception. Previous studies show that during rhythmic auditory-motor synchronization tasks, better performance is related to stronger motor system engagement. However, whether individual differences in auditory-motor interactions influence higher-level rhythmic predictions is unknown. Here, we used electroencephalography during a naturalistic music listening task to assess the neural tracking of rhythmic and melodic predictions generated from (short-term) local contextual information and (long-term) experience using the Information Dynamics of Music model. We combined a multivariate temporal response function approach with two behavioral measures of auditory-motor synchronization (whispering and finger tapping). We found that stronger auditory-motor synchronization predicted stronger neural tracking of lower-level temporal aspects of the music signal, i.e. acoustic envelope and note onset. Across participants, higher-level (short- and long-term) predictions were also neurally tracked, with neural tracking stronger for rhythmic than melodic predictions. Importantly, our evidence suggests individual differences in the weighting of musical predictions. Individuals with stronger auditory-motor synchronization showed stronger neural tracking of rhythmic compared to melodic predictions, and this effect was especially pronounced for short-term predictions. Our findings demonstrate that the motor system is critically involved at several processing levels even in purely perceptual music tasks, and pave the way for understanding individual differences in the weighting of rhythmic and melodic predictions during music listening. Significance statementOur ability to make musical predictions affects our perception of music. Understanding individual differences in predictive processing may allow for differential diagnostics and interventions in clinical disorders such as rhythm disorders or hearing impairment. In an electrophysiological study, we found evidence that the motor system is implicated in predictive processes during perception of music. Specifically, we find advanced neural processing of acoustic temporal features and stronger weighting of short- and long-term rhythmic musical predictions in individuals who recruit the motor system more strongly. Likely, in individuals with high compared to low auditory-motor synchronization strength, the motor system facilitates temporal processing at different levels: at the level of acoustic temporal structure processing, and at higher-level processing of rhythmic musical predictions.

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Attentional engagement with target and distractor streams predicts speech comprehension in multitalker environments

Understanding speech while ignoring competing speech streams in the surrounding environment is challenging. Previous studies have demonstrated that attention shapes the neural representation of speech features. Attended streams are typically represented more strongly than unattended ones, suggesting either enhancement of the attended or suppression of the unattended stream. However, it is unclear how these complementary processes support attentional filtering and speech comprehension on different hierarchical levels. In this study, we used multivariate temporal response functions to analyze the EEG signals of 43 young adults (24 women), examining the relationship between the neural tracking of acoustic and higher-level linguistic features and a fine-grained speech comprehension measure. We show that the neural tracking of word and phoneme onsets and word-level linguistic features in the attended stream predicted comprehension at the individual single-trial level. Moreover, acoustic tracking of the ignored speech stream was positively correlated with comprehension performance, whereas word level linguistic neural tracking of the ignored stream was negatively correlated with comprehension. Collectively, our results suggest that attentional filtering during speech comprehension requires target enhancement as well as distractor suppression at different hierarchical levels. Significance StatementIn social settings, speech comprehension is often challenged by the presence of multiple speakers talking simultaneously. The ability to focus on a relevant stream while ignoring irrelevant speech information in the background is crucial for successful and efficient interpersonal interactions. However, the precise neural mechanisms underlying this selective filtering process remain unclear. We establish the interplay of acoustic and higher-level information as objective markers of attentional selection and comprehension success.

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Endogenous auditory and motor brain rhythms predictindividual speech tracking

Slow, endogenous brain rhythms in auditory cortex are hypothesized to track acoustic amplitude modulations during speech comprehension. Temporal predictions from the motor system are thought to enhance this tracking. However, direct evidence for the involvement of endogenous auditory and motor brain rhythms is lacking. Combining magnetoencephalographic recordings with behavioral data, we here show that endogenous peak frequencies of individuals resting-state theta rhythm in superior temporal gyrus predict speech tracking during comprehension. Importantly, endogenous rates of speech motor areas predicted auditory-cortical speech tracking only in individuals with high auditory-motor synchronization profiles. Higher rates in the supplementary motor area, and lower rates in inferior frontal gyrus, predicted stronger tracking. These findings align with participants behavioral data and provide compelling support for oscillatory accounts of auditory-motor interactions during speech perception. Interestingly, working memory capacity predicted speech comprehension performance particularly in individuals with low auditory-motor synchronization profiles. The findings highlight two partially independent speech processing routes across individuals: an auditory-motor route, related to enhanced comprehension performance, and an auditory working-memory route.

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Cortical and behavioural tracking of rhythm in music: Effects of pitch predictability, enjoyment, and expertise

The cortical tracking of stimulus features (such as the sound envelope) is a crucial neural requisite of how we process continuous music. We here tested whether cortical tracking of the beat, typically related to rhythm processing, is modulated by pitch predictability and other top-down factors. Participants listened to tonal (high pitch predictability) and atonal (low pitch predictability) music while undergoing EEG, and we analysed their cortical tracking of the acoustic envelope. Interestingly, cortical envelope tracking was stronger while listening to atonal than tonal music, likely reflecting listeners violated pitch expectations. Envelope tracking was also stronger with more expertise and enjoyment. Furthermore, we analysed cortical tracking of pitch surprisal (using IDyOM) and show that listeners expectations for tonal and atonal music match those computed by the IDyOM model, with higher surprisal (prediction errors) for atonal than tonal music. Behaviourally, we measured participants ability to tap along to the beat of tonal and atonal sequences in two experiments. In both experiments, finger-tapping performance was better in the tonal than the atonal condition, indicating a positive effect of pitch predictability on behavioural rhythm processing. Cortical envelope tracking predicted tapping performance for tonal music, as did pitch surprisal tracking for atonal music, indicating that conditions of high and low predictability might impose different processing regimes. We show that cortical envelope tracking, beyond reflecting musical rhythm processing, is modulated by pitch predictability, as well as musical expertise and enjoyment. Taken together, our results show various ways in which those top-down factors impact musical rhythm processing.

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Preferred auditory temporal processing regimes and auditory-motor interactions

Decoding the rich temporal dynamics of complex sounds such as speech is constrained by the underlying neuronal processing mechanisms. Oscillatory theories suggest the existence of one optimal perceptual performance regime at auditory stimulation rates in the delta to theta range (<10 Hz), but reduced performance in the alpha range (10-14 Hz) is controversial. Additionally, the widely discussed motor system contribution to timing remains unclear. We measured rate discrimination thresholds between 4-15 Hz, and auditory-motor coupling strength was estimated through auditory-motor synchronization. In a Bayesian model comparison, high auditory-motor synchronizers showed a larger range of constant optimal temporal judgments than low synchronizers, with performance decreasing in the alpha range. This evidence for optimal auditory processing in the theta range is consistent with preferred oscillatory regimes in auditory cortex that compartmentalize stimulus encoding and processing. The findings suggest, remarkably, that increased auditory-motor interaction might extend such an optimal range towards faster rates.

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Acoustically driven cortical delta oscillations underpin perceptual chunking

Oscillation-based models of speech perception postulate a cortical computational principle by which decoding is performed within a window structure derived by a segmentation process. In the syllable level segmentation is realized by a theta oscillator. We provide evidence for an analogous role of a delta oscillator at the phrasal level. We recorded MEG while participants performed a target identification task. Random-digit strings, with phrasal chunks of two digits, were presented at chunk rates inside or outside of the delta range. Strong periodicities were elicited by acoustic-driven chunk rates inside of delta, in superior and middle temporal areas and speech-motor integration areas. Periodicities were diminished or absent for chunk rates outside of the delta range, closely in line with behavioral performance. No periodicities were observed for top-down driven chunking conditions. Our findings show that phrasal chunking is correlated with acoustic-driven delta oscillations, expressing anatomically specific patterns of neuronal periodicities.Competing Interest StatementThe authors have declared no competing interest.View Full Text

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Data-driven classification of spectral profiles reveals brain region-specific plasticity

Congenital blindness has been shown to result in behavioral adaptation and neuronal reorganization, but the underlying neuronal mechanisms are largely unknown. Brain rhythms are characteristic for anatomically defined brain regions and provide a putative mechanistic link to cognitive processes. In a novel approach, using magnetoencephalography resting state data of congenitally blind and sighted humans, deprivation-related changes in spectral profiles were mapped to the cortex using clustering and classification procedures. Altered spectral profiles in visual areas suggest changes in visual alpha-gamma band inhibitory-excitatory circuits. Remarkably, spectral profiles were also altered in auditory and right frontal areas showing increased power in theta-to-beta frequency bands in blind compared to sighted individuals, possibly related to adaptive auditory and higher-cognitive processing. Moreover, occipital alpha correlated with microstructural white matter properties extending bilaterally across posterior parts of the brain. We provide evidence that visual deprivation selectively modulates spectral profiles, possibly reflecting structural and functional adaptation.

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Dynamics of functional networks for syllable and word-level processing

Speech comprehension requires the ability to temporally segment the acoustic input for higher-level linguistic analysis. Oscillation-based approaches suggest that low-frequency auditory cortex oscillations track syllable-sized acoustic information and therefore emphasize the relevance of syllabic-level processing for speech segmentation. Most linguistic approaches, however, focus on mapping from acoustic-phonemic representations to the lexical level. How syllabic processing interacts with higher levels of speech processing, beyond segmentation, including the anatomical and neurophysiological characteristics of the networks involved, is debated. Here we investigate the effects of lexical processing and the interactions with (acoustic) syllable processing by examining MEG data recorded in two experiments using a frequency-tagging paradigm. Participants listened to disyllabic words presented at a rate of 4 syllables/sec. Two conjectures were evaluated: (i) lexical processing of words activates a network that interacts with syllable processing; and (ii) syllable transitions contribute to word-level processing. We show that lexical content activated a left-lateralized frontal and superior and middle temporal network and increased the interaction between left middle temporal areas and auditory cortex (phase-phase coupling). Mere syllable-transition information, in contrast, activated a bilateral superior-, middle temporal and inferior frontal network and increased the interaction between those areas. Word and syllable processing interacted in superior and middle temporal areas (cross-frequency coupling), whereas syllable tracking (cerebro-acoustic coherence) decreased when word-level information was present. The data provide a new perspective on speech comprehension by demonstrating a contribution of an acoustic-syllabic to lexical processing route.\n\nSignificance statementThe comprehension of speech requires integrating information at multiple time scales, including phonemic, syllabic, and word scales. Typically, we think of decoding speech in the service of recognizing words as a process that maps from phonemic units to words. Recent neurophysiological evidence, however, has highlighted the relevance of syllable-sized chunks for segmenting speech. Is there more to recognizing spoken language? We provide neural evidence for brain network dynamics that support an interaction of lexical with syllable-level processing. We identify cortical networks that differ depending on whether lexical-semantic information versus low-level syllable-transition information is processed. Word- and syllable-level processing interact within MTG and STG. The data enrich our understanding of comprehension by implicating a mapping from syllabic to lexical representations.

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Working Memory Training Integrates Visual Cortex into Beta-Band Networks in Congenitally Blind Individuals

Congenitally blind individuals activate the visual cortex during non-visual tasks. Such crossmodal reorganization is likely associated with changes in large-scale functional connectivity, the spectral characteristics of which can be assessed by analysis of neural oscillations. To test visual cortical integration into working memory networks, we recorded magnetoencephalographic data from congenitally blind and sighted individuals during resting state as well as during a voice-based working memory task prior to and following working memory training with voices, or tactile stimuli or a training-control condition. Auditory training strengthened beta-band (17.5-22.5 Hz) connectivity (imaginary coherency) in the blind and theta-band (2.5-5 Hz) connectivity in the sighted during the task, suggesting different neural coupling mechanisms. In the sighted, theta-band connectivity increased between brain areas involved in auditory working memory (inferior frontal, superior temporal, insular cortex). In the blind, beta-band networks largely emerged during the training, and connectivity increased between brain areas involved in auditory working memory and the visual cortex. The prominent involvement of the right fusiform face area in this beta-band network suggests a task-specific integration of visual cortex. Our findings highlight large-scale interactions as a key mechanism of functional reorganization following congenital blindness, and provide new insights into the spectral characteristics of the mechanism.

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