Dual Representations of Temporal Modulations in Human Auditory Cortex PDF Download

Author: Huizhen Tang
Publisher:
ISBN:
Category : Auditory cortex
Languages : en
Pages : 169

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Book Description
Our ability to understand speech and other sounds relies crucially on the capacity to detect and perceive temporal amplitude fluctuations in the range of about 1-100 Hz. However, most individual neurons in auditory cortex are capable of precisely aligning their activities only to modulation rates at the lower end of this range. This raises the question of how higher modulation rates might be encoded, and of how the auditory cortex might be organised to accommodate the full range of perceptually relevant amplitude envelope modulations. Here we show, with noninvasive magnetoencephalography and electroencephalography measurements, that population oscillatory responses of human auditory cortex transition between a mode of strong phase locking to modulation rates below about 40-50 Hz, to a non phase-locked mode of responding at rates higher than about 50 Hz. Such dual response modes are predictable from the behaviours of single neurons in auditory cortex of non-human primates, but only the low rate phase locking mode has been previously observed in the neuronal population responses indexed in human MEG/EEG recordings. Taken together, the single neuron and MEG and EEG results from current thesis work suggest that two distinct types of neuronal encoding are required to represent the full range of temporal modulation rates that are relevant to everyday perception.

Author: David Poeppel
Publisher: Springer Science & Business Media
ISBN: 1461423139
Category : Science
Languages : en
Pages : 404

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Book Description
We live in a complex and dynamically changing acoustic environment. To this end, the auditory cortex of humans has developed the ability to process a remarkable amount of diverse acoustic information with apparent ease. In fact, a phylogenetic comparison of auditory systems reveals that human auditory association cortex in particular has undergone extensive changes relative to that of other species, although our knowledge of this remains incomplete. In contrast to other senses, human auditory cortex receives input that is highly pre-processed in a number of sub-cortical structures; this suggests that even primary auditory cortex already performs quite complex analyses. At the same time, much of the functional role of the various sub-areas in human auditory cortex is still relatively unknown, and a more sophisticated understanding is only now emerging through the use of contemporary electrophysiological and neuroimaging techniques. The integration of results across the various techniques signify a new era in our knowledge of how human auditory cortex forms basis for auditory experience. This volume on human auditory cortex will have two major parts. In Part A, the principal methodologies currently used to investigate human auditory cortex will be discussed. Each chapter will first outline how the methodology is used in auditory neuroscience, highlighting the challenges of obtaining data from human auditory cortex; second, each methods chapter will provide two or (at most) three brief examples of how it has been used to generate a major result about auditory processing. In Part B, the central questions for auditory processing in human auditory cortex are covered. Each chapter can draw on all the methods introduced in Part A but will focus on a major computational challenge the system has to solve. This volume will constitute an important contemporary reference work on human auditory cortex. Arguably, this will be the first and most focused book on this critical neurological structure. The combination of different methodological and experimental approaches as well as a diverse range of aspects of human auditory perception ensures that this volume will inspire novel insights and spurn future research.

Author: Jeffery A. Winer
Publisher: Springer Science & Business Media
ISBN: 1441900748
Category : Science
Languages : en
Pages : 711

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Book Description
There has been substantial progress in understanding the contributions of the auditory forebrain to hearing, sound localization, communication, emotive behavior, and cognition. The Auditory Cortex covers the latest knowledge about the auditory forebrain, including the auditory cortex as well as the medial geniculate body in the thalamus. This book will cover all important aspects of the auditory forebrain organization and function, integrating the auditory thalamus and cortex into a smooth, coherent whole. Volume One covers basic auditory neuroscience. It complements The Auditory Cortex, Volume 2: Integrative Neuroscience, which takes a more applied/clinical perspective.

Author: Jessica Liberty Sackville Hamilton
Publisher:
ISBN:
Category :
Languages : en
Pages : 104

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Book Description
The brain contains neurons of many different types interacting in complex functional circuits. To process sensory information these cells work in concert to form representations of the external world. In the auditory cortex, this involves integrating information from different cell types across an orderly anatomical structure of layers and columns. Representations can be observed at the level of single cells, cortical microcircuits, and large-scale sensory maps. The relationship between single cell properties and circuits within the auditory cortex, however, is still poorly understood. Furthermore, the structure-function relationships uncovered by neuroscientific study may crucially depend on the stimuli used to probe the system. This thesis brings together work from each of these different levels to describe how sounds are represented in the cortex, how this representation changes with experience, and how different cells contribute to cortical representation. First, I describe how the statistics of sound stimuli influence response properties in the mouse primary auditory cortex by comparing responses to pure tones and natural sounds (ultrasonic vocalizations). I also compare these responses to a temporally reversed vocalization to determine whether a sound with similar spectrotemporal content but no ethological relevance is represented similarly. When comparing pure tones and vocalizations, I find that the temporal response properties are similar, but that spectral response properties (e.g. frequency selectivity) often differ substantially. In particular, there are multiple sites that responded to vocalizations with frequency content outside their classical tone-derived receptive field, suggesting some specificity for behaviorally relevant sounds. When comparing forward and backward vocalizations, temporal responses are similar, but frequency bandwidth and characteristic frequency differs significantly across the population. Thus, the behaviorally relevant sound appears to be represented differently from non-behaviorally relevant synthetic and naturalistic sounds. The response properties of auditory neurons are not fixed, but rather depend on experience. In the next study, I examine how exposure to pulsed noise during different sensitive windows of the auditory critical period affects single site properties as well as circuit-level dynamics. On the single site level, I find that early exposure to pulsed noise increases receptive field thresholds and decreases frequency selectivity, while late noise exposure increases frequency bandwidths as well as spontaneous and evoked firing rates. To describe changes in functional microcircuits, I use the Ising model, which describes pairwise interactions between simultaneously recorded sites in the auditory cortex as well as interactions between sites and the stimuli that modulate them. I find that early noise exposure decreases stimulus drive, whereas late noise exposure does not change the strength of sound inputs but rather decreases the spread of functional connections from the deep to the superficial layers across sites with different frequency selectivity. Finally, I use a combination of optogenetic tools and computational methods to describe how the activity of a specific class of inhibitory neurons affects network connectivity in the auditory cortex. I examine the contribution of parvalbumin-positive (PV+) inhibitory interneurons, which make up around half of the inhibitory neurons in the cortex. These neurons are known to be involved in the generation of gamma oscillations, and their maturation corresponds with the end of the auditory critical period for plasticity. Using Ising models in tandem with linear-nonlinear vector autoregressive models, I show that stimulating PV+ neurons increases feedforward information flow through cortical circuits without changing lateral interactions within the same layers.

Author: Gastone G. Celesia
Publisher: Elsevier
ISBN: 0444626298
Category : Medical
Languages : en
Pages : 723

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Book Description
The Human Auditory System: Fundamental Organization and Clinical Disorders provides a comprehensive and focused reference on the neuroscience of hearing and the associated neurological diagnosis and treatment of auditory disorders. This reference looks at this dynamic area of basic research, a multidisciplinary endeavor with contributions from neuroscience, clinical neurology, cognitive neuroscience, cognitive science communications disorders, and psychology, and its dramatic clinical application. A focused reference on the neuroscience of hearing and clinical disorders Covers both basic brain science, key methodologies and clinical diagnosis and treatment of audiology disorders Coverage of audiology across the lifespan from birth to elderly topics

Author: Paul Thomas Fillmore
Publisher:
ISBN: 9781109524635
Category :
Languages : en
Pages : 77

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Book Description
We have described a set of experiments examining temporal organization in the auditory system on several timescales, using several stimulus types, to gain a broad picture of the representation of temporal features of sound in human auditory cortex. Experiment one examined the common claim of left hemisphere specialization for speech based on temporal factors (Schwartz & Tallal, 1980, Zatorre et al., 2002), and how these patterns could be modulated by task demands. Subjects listened to words with or without rapid formant transitions, and performed either a semantic or a phonemic task. We found that in the context of whole-word natural language processing, the presence of rapid temporal change does not result in expected left-lateralized effects. When participants attended to sound analysis, stimulus effects became more likely, but were found in both hemispheres. Our results stress the importance of task demands in evaluating theories of auditory perception. Experiment two used a novel stimulus in fMRI, repeated frozen noise, to examine periodotopic organization in auditory cortex for periods of 25, 50, 100, 200 and 400 ms. We found that primary auditory structures were sensitive to all periodicities, with each condition activating distinct additional areas in the temporal plane, and the most anterior areas preferentially sensitive to the longest periods. Despite the use of stimuli within timescales described elsewhere as preferentially driving hemispheric lateralization patterns (Poeppel, 2003), no effects of hemisphere were evident, suggesting that temporal hierarchical organization within hemisphere may be a more dominant structure than that across hemispheres. In experiment three, we used a modified auditory oddball paradigm to find regions of auditory cortex that code for sequence processing for sequences of differing lengths (1, 3 or 6 tones). We found regions sensitive to coding stimulus deviance throughout the temporal lobes, bilaterally. Additionally, downstream areas (i.e. anterior temporal and sensorimotor regions) were increasingly recruited with increasing sequence length. Different areas were active for the three and six-tone conditions, with the six-tone sequence activating the most anterior regions. These spatial patterns, along with those from experiment two, suggest the possibility of a length-based organization for sound in the human temporal lobe.

Author: Kevin Ochsner
Publisher: Oxford University Press
ISBN: 0199988692
Category : Medical
Languages : en
Pages : 638

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Book Description
A rich source of authoritative information that supports reading and study in the field of cognitive neuroscience, this two-volume handbook reviews the current state-of-the-science in all major areas of the field.

Author: Tobias Overath
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Author: Reiko Matsushita
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
"Hemispheric asymmetries in processing of different acoustic features are well-known aspect of the auditory cortex. According to one model; the auditory cortex in the left hemisphere is tuned to process rapidly changing temporal information, which are abundant in human speech, and the auditory cortex in the right hemisphere play a dominant role in spectral processing hence significantly contributing to pitch processing. In the past, this spectral-temporal model of the auditory cortex has been addressed mainly using neuroimaging techniques, which inform us about correlational relationships between behaviors and brain activities. In the present thesis, we seek causal evidence that supports the spectral-temporal model, focusing on the right-hemisphere dominance in pitch processing, using transcranial direct current stimulation (tDCS).tDCS is a relatively new technique, which has potential to allow us to address the causal role of certain brain activities, to explore functional connectivity, and possibly to help different neurological and psychological conditions. However, little is known about the mechanisms of tDCS, especially in the auditory domain. We aimed to elucidate the mechanisms of tDCS in the human auditory system, and to develop a protocol to assess the right-hemisphere dominance in pitch processing and learning using tDCS.In the first study (chapter 2), we established a behavioural paradigm to test tDCS-induced effect on pitch processing using a pitch discrimination test called micromelody discrimination task. In this task short tone patterns using small (

Author: Steven Greenberg
Publisher: Psychology Press
ISBN: 1135624909
Category : Language Arts & Disciplines
Languages : en
Pages : 443

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Book Description
The human species is largely defined by its use of spoken language, so integral is speech communication to behavior and social interaction. Despite its importance in everyday life, comparatively little is known about the auditory mechanisms that underlie the ability to understand language. The current volume examines the perception and processing of speech from the perspective of the hearing system. The chapters in this book describe a comprehensive set of approaches to the scientific study of speech and hearing, ranging from anatomy and physiology, to psychophysics and perception, and computational modeling. The auditory basis of speech is examined within a biological and an evolutionary context, and its relevance to applied domains such as communication disorders and speech technology discussed in detail. This volume will be of interest to scientists, engineers, and clinicians whose professional work pertains to any aspect of spoken language or hearing science.