Neural Mechanisms of Music and Language

Author(s):  
Mattson Ogg ◽  
L. Robert Slevc

Music and language are uniquely human forms of communication. What neural structures facilitate these abilities? This chapter conducts a review of music and language processing that follows these acoustic signals as they ascend the auditory pathway from the brainstem to auditory cortex and on to more specialized cortical regions. Acoustic, neural, and cognitive mechanisms are identified where processing demands from both domains might overlap, with an eye to examples of experience-dependent cortical plasticity, which are taken as strong evidence for common neural substrates. Following an introduction describing how understanding musical processing informs linguistic or auditory processing more generally, findings regarding the major components (and parallels) of music and language research are reviewed: pitch perception, syntax and harmonic structural processing, semantics, timbre and speaker identification, attending in auditory scenes, and rhythm. Overall, the strongest evidence that currently exists for neural overlap (and cross-domain, experience-dependent plasticity) is in the brainstem, followed by auditory cortex, with evidence and the potential for overlap becoming less apparent as the mechanisms involved in music and speech perception become more specialized and distinct at higher levels of processing.

2020 ◽  
Author(s):  
Emily J. Allen ◽  
Juraj Mesik ◽  
Kendrick N. Kay ◽  
Andrew J. Oxenham

SUMMARYFrequency-to-place mapping, or tonotopy, is a fundamental organizing principle from the earliest stages of auditory processing in the cochlea to subcortical and cortical regions. Although cortical maps are referred to as tonotopic, previous studies employed sounds that covary in spectral content and higher-level perceptual features such as pitch, making it unclear whether these maps are inherited from cochlear organization and are indeed tonotopic, or instead reflect transformations based on higher-level features. We used high-resolution fMRI to measure BOLD responses in 10 participants as they listened to pure tones that varied in frequency or complex tones that independently varied in either spectral content or fundamental frequency (pitch). We show that auditory cortical gradients are in fact a mixture of maps organized both by spectral content and pitch. Consistent with hierarchical organization, primary regions were tuned predominantly to spectral content, whereas higher-level pitch tuning was observed bilaterally in surrounding non-primary regions.


2011 ◽  
Vol 105 (6) ◽  
pp. 2634-2646 ◽  
Author(s):  
Joji Tsunada ◽  
Jung Hoon Lee ◽  
Yale E. Cohen

A “ventral” auditory pathway in nonhuman primates that originates in the core auditory cortex and ends in the prefrontal cortex is thought to be involved in components of nonspatial auditory processing. Previous work from our laboratory has indicated that neurons in the prefrontal cortex reflect monkeys' decisions during categorical judgments. Here, we tested the role of the superior temporal gyrus (STG), a region of the secondary auditory cortex that is part of this ventral pathway, during similar categorical judgments. While monkeys participated in a match-to-category task and reported whether two consecutive auditory stimuli belonged to the same category or to different categories, we recorded spiking activity from STG neurons. The auditory stimuli were morphs of two human-speech sounds ( bad and dad). We found that STG neurons represented auditory categories. However, unlike activity in the prefrontal cortex, STG activity was not modulated by the monkeys' behavioral reports (choices). This finding is consistent with the anterolateral STG's role as a part of functional circuit involved in the coding, representation, and perception of the nonspatial features of an auditory stimulus.


2020 ◽  
Vol 46 (5) ◽  
pp. 1053-1059
Author(s):  
Victor W Kilonzo ◽  
Robert A Sweet ◽  
Jill R Glausier ◽  
Matthew W Pitts

Abstract Aberrant processing of auditory stimuli is a prominent feature of schizophrenia (SZ). Prior studies have chronicled histological abnormalities in the auditory cortex of SZ subjects, but whether deficits exist at upstream, subcortical levels has yet to be established. En route to the auditory cortex, ascending information is integrated in the inferior colliculus (IC), a highly gamma amino butyric acid (GABA) ergic midbrain structure that is critically involved in auditory processing. The IC contains a dense population of parvalbumin-immunoreactive interneurons (PVIs), a cell type characterized by increased metabolic demands and enhanced vulnerability to oxidative stress. During development, PVIs are preferentially surrounded by perineuronal nets (PNNs), specialized extracellular matrix structures that promote redox homeostasis and excitatory/inhibitory balance. Moreover, in SZ, deficits in PVIs, PNNs, and the GABA synthesizing enzyme, glutamic acid decarboxylase (Gad67), have been extensively documented in cortical regions. Yet, whether similar impairments exist in the IC is currently unknown. Thus, we compared IC samples of age- and sex-matched pairs of SZ and unaffected control subjects. SZ subjects exhibited lower levels of Gad67 immunoreactivity and a decreased density of PVIs and PNNs within the IC. These findings provide the first histological evidence of IC GABAergic abnormalities in SZ and suggest that SZ-related auditory dysfunction may stem, in part, from altered IC inhibitory tone.


2012 ◽  
Vol 107 (8) ◽  
pp. 2042-2056 ◽  
Author(s):  
Tobias Overath ◽  
Yue Zhang ◽  
Dan H. Sanes ◽  
David Poeppel

Hierarchical models of auditory processing often posit that optimal stimuli, i.e., those eliciting a maximal neural response, will increase in bandwidth and decrease in modulation rate as one ascends the auditory neuraxis. Here, we tested how bandwidth and modulation rate interact at several loci along the human central auditory pathway using functional MRI in a cardiac-gated, sparse acquisition design. Participants listened passively to both narrowband (NB) and broadband (BB) carriers (1/4- or 4-octave pink noise), which were jittered about a mean sinusoidal amplitude modulation rate of 0, 3, 29, or 57 Hz. The jittering was introduced to minimize stimulus-specific adaptation. The results revealed a clear difference between spectral bandwidth and temporal modulation rate: sensitivity to bandwidth (BB > NB) decreased from subcortical structures to nonprimary auditory cortex, whereas sensitivity to slow modulation rates was largest in nonprimary auditory cortex and largely absent in subcortical structures. Furthermore, there was no parametric interaction between bandwidth and modulation rate. These results challenge simple hierarchical models, in that BB stimuli evoked stronger responses in primary auditory cortex (and subcortical structures) rather than nonprimary cortex. Furthermore, the strong preference for slow modulation rates in nonprimary cortex demonstrates the compelling global sensitivity of auditory cortex to modulation rates that are dominant in the principal signals that we process, e.g., speech.


2021 ◽  
Author(s):  
Fabian Schmidt ◽  
Ya-Ping Chen ◽  
Anne Keitel ◽  
Sebastian Rösch ◽  
Ronny Hannemann ◽  
...  

ABSTRACTThe most prominent acoustic features in speech are intensity modulations, represented by the amplitude envelope of speech. Synchronization of neural activity with these modulations is vital for speech comprehension. As the acoustic modulation of speech is related to the production of syllables, investigations of neural speech tracking rarely distinguish between lower-level acoustic (envelope modulation) and higher-level linguistic (syllable rate) information. Here we manipulated speech intelligibility using noise-vocoded speech and investigated the spectral dynamics of neural speech processing, across two studies at cortical and subcortical levels of the auditory hierarchy, using magnetoencephalography. Overall, cortical regions mostly track the syllable rate, whereas subcortical regions track the acoustic envelope. Furthermore, with less intelligible speech, tracking of the modulation rate becomes more dominant. Our study highlights the importance of distinguishing between envelope modulation and syllable rate and provides novel possibilities to better understand differences between auditory processing and speech/language processing disorders.Abstract Figure


Author(s):  
Vidhusha Srinivasan ◽  
N. Udayakumar ◽  
Kavitha Anandan

Background: The spectrum of autism encompasses High Functioning Autism (HFA) and Low Functioning Autism (LFA). Brain mapping studies have revealed that autism individuals have overlaps in brain behavioural characteristics. Generally, high functioning individuals are known to exhibit higher intelligence and better language processing abilities. However, specific mechanisms associated with their functional capabilities are still under research. Objective: This work addresses the overlapping phenomenon present in autism spectrum through functional connectivity patterns along with brain connectivity parameters and distinguishes the classes using deep belief networks. Methods: The task-based functional Magnetic Resonance Images (fMRI) of both high and low functioning autistic groups were acquired from ABIDE database, for 58 low functioning against 43 high functioning individuals while they were involved in a defined language processing task. The language processing regions of the brain, along with Default Mode Network (DMN) have been considered for the analysis. The functional connectivity maps have been plotted through graph theory procedures. Brain connectivity parameters such as Granger Causality (GC) and Phase Slope Index (PSI) have been calculated for the individual groups. These parameters have been fed to Deep Belief Networks (DBN) to classify the subjects under consideration as either LFA or HFA. Results: Results showed increased functional connectivity in high functioning subjects. It was found that the additional interaction of the Primary Auditory Cortex lying in the temporal lobe, with other regions of interest complimented their enhanced connectivity. Results were validated using DBN measuring the classification accuracy of 85.85% for high functioning and 81.71% for the low functioning group. Conclusion: Since it is known that autism involves enhanced, but imbalanced components of intelligence, the reason behind the supremacy of high functioning group in language processing and region responsible for enhanced connectivity has been recognized. Therefore, this work that suggests the effect of Primary Auditory Cortex in characterizing the dominance of language processing in high functioning young adults seems to be highly significant in discriminating different groups in autism spectrum.


2021 ◽  
Vol 11 (1) ◽  
pp. 112-128
Author(s):  
Caitlin N. Price ◽  
Deborah Moncrieff

Communication in noise is a complex process requiring efficient neural encoding throughout the entire auditory pathway as well as contributions from higher-order cognitive processes (i.e., attention) to extract speech cues for perception. Thus, identifying effective clinical interventions for individuals with speech-in-noise deficits relies on the disentanglement of bottom-up (sensory) and top-down (cognitive) factors to appropriately determine the area of deficit; yet, how attention may interact with early encoding of sensory inputs remains unclear. For decades, attentional theorists have attempted to address this question with cleverly designed behavioral studies, but the neural processes and interactions underlying attention’s role in speech perception remain unresolved. While anatomical and electrophysiological studies have investigated the neurological structures contributing to attentional processes and revealed relevant brain–behavior relationships, recent electrophysiological techniques (i.e., simultaneous recording of brainstem and cortical responses) may provide novel insight regarding the relationship between early sensory processing and top-down attentional influences. In this article, we review relevant theories that guide our present understanding of attentional processes, discuss current electrophysiological evidence of attentional involvement in auditory processing across subcortical and cortical levels, and propose areas for future study that will inform the development of more targeted and effective clinical interventions for individuals with speech-in-noise deficits.


Author(s):  
Josef P. Rauschecker

When one talks about hearing, some may first imagine the auricle (or external ear), which is the only visible part of the auditory system in humans and other mammals. Its shape and size vary among people, but it does not tell us much about a person’s abilities to hear (except perhaps their ability to localize sounds in space, where the shape of the auricle plays a certain role). Most of what is used for hearing is inside the head, particularly in the brain. The inner ear transforms mechanical vibrations into electrical signals; then the auditory nerve sends these signals into the brainstem, where intricate preprocessing occurs. Although auditory brainstem mechanisms are an important part of central auditory processing, it is the processing taking place in the cerebral cortex (with the thalamus as the mediator), which enables auditory perception and cognition. Human speech and the appreciation of music can hardly be imagined without a complex cortical network of specialized regions, each contributing different aspects of auditory cognitive abilities. During the evolution of these abilities in higher vertebrates, especially birds and mammals, the cortex played a crucial role, so a great deal of what is referred to as central auditory processing happens there. Whether it is the recognition of one’s mother’s voice, listening to Pavarotti singing or Yo-Yo Ma playing the cello, hearing or reading Shakespeare’s sonnets, it will evoke electrical vibrations in the auditory cortex, but it does not end there. Large parts of frontal and parietal cortex receive auditory signals originating in auditory cortex, forming processing streams for auditory object recognition and auditory-motor control, before being channeled into other parts of the brain for comprehension and enjoyment.


2016 ◽  
Vol 115 (1) ◽  
pp. 510-519
Author(s):  
Sarah Wirtssohn ◽  
Bernhard Ronacher

Temporal resolution and the time courses of recovery from acute adaptation of neurons in the auditory pathway of the grasshopper Locusta migratoria were investigated with a response recovery paradigm. We stimulated with a series of single click and click pair stimuli while performing intracellular recordings from neurons at three processing stages: receptors and first and second order interneurons. The response to the second click was expressed relative to the single click response. This allowed the uncovering of the basic temporal resolution in these neurons. The effect of adaptation increased with processing layer. While neurons in the auditory periphery displayed a steady response recovery after a short initial adaptation, many interneurons showed nonlinear effects: most prominent a long-lasting suppression of the response to the second click in a pair, as well as a gain in response if a click was preceded by a click a few milliseconds before. Our results reveal a distributed temporal filtering of input at an early auditory processing stage. This set of specified filters is very likely homologous across grasshopper species and thus forms the neurophysiological basis for extracting relevant information from a variety of different temporal signals. Interestingly, in terms of spike timing precision neurons at all three processing layers recovered very fast, within 20 ms. Spike waveform analysis of several neuron types did not sufficiently explain the response recovery profiles implemented in these neurons, indicating that temporal resolution in neurons located at several processing layers of the auditory pathway is not necessarily limited by the spike duration and refractory period.


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