Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Speech Sound Representation And Experience Dependent Plasticity In The Rat Auditory System PDF full book. Access full book title Speech Sound Representation And Experience Dependent Plasticity In The Rat Auditory System.
| Author | : Pritesh K. Pandya |
| Publisher | : |
| Total Pages | : 568 |
| Release | : 2005 |
| Genre | : Auditory cortex |
| ISBN | : |
| Author | : Heesoo Kim |
| Publisher | : |
| Total Pages | : 94 |
| Release | : 2011 |
| Genre | : |
| ISBN | : |
The early acoustic environment plays a crucial role in how the brain represents sounds and how language phonemes are perceived. Human infants are born with the capacity to distinguish phonemes from virtually all languages, but very quickly change their perceptual ability to match that of their primary language. This has been described as the Perceptual Magnet Effect in humans, where phoneme tokens are perceived to be more similar than they physically are, leading to decreased discrimination ability. Early development is marked by distinct critical periods, when cortical regions are highly plastic and particularly sensitive to sensory input. These lasting alterations in cortical sensory representation may directly impact the perception of the external world. My thesis is comprised of three different studies, all of which investigate the role of the developmental acoustic environment on cortical representation and the behavioral consequence of altered cortical representation. Passive exposure to pure-tone pips during the auditory critical period can lead to over-representation of the exposure tone frequency in the primary auditory cortex (A1) of rats. This over-representation is associated with decreased discrimination ability of that frequency, similar to the Perceptual Magnet Effect in humans. Another hallmark of human language is categorical perception. Using a computational model of A1, I show that certain representation patterns (which may be achieved with passive exposure to two distinct pure-tone pips) in A1 can lead to categorical perception in rats. This suggests that cortical representation may be a mechanism that drives categorical perception. Rodents are socially vocal animals whose con-specific calls are often presented in bouts in the ultrasonic frequency range. These calls are vocalized at ethologically relevant repetition rates. I show that pure-tone pips that are presented at the ethological repetition rate (but not slower or faster rates) during the auditory critical period lead to over-representation of the pure-tone frequency. A certain subclass of ultrasonic vocalizations, the pup isolation calls, occurs during the auditory critical period. I show that there is over representation of ultrasonic vocalization frequencies in the rat A1. This preferential representation is experience-dependent and is associated with higher discrimination ability.
| Author | : Thomas D. Wickens |
| Publisher | : Oxford University Press |
| Total Pages | : 284 |
| Release | : 2001-10-11 |
| Genre | : Psychology |
| ISBN | : 9780195357806 |
Signal detection theory, as developed in electrical engineering and based on statistical decision theory, was first applied to human sensory discrimination about 40 years ago. The theory's intent was to explain how humans discriminate and how we might use reliable measures to quantify this ability. An interesting finding of this work is that decisions are involved even in the simplest of discrimination tasks--say, determining whether or not a sound has been heard (a yes-no decision). Detection theory has been applied to a host of varied problems (for example, measuring the accuracy of diagnostic systems, survey research, reliability of lie detection tests) and extends far beyond the detection of signals. This book is a primer on signal detection theory, useful for both undergraduates and graduate students.
| Author | : Jose Miguel Cisneros-Franco |
| Publisher | : |
| Total Pages | : |
| Release | : 2020 |
| Genre | : |
| ISBN | : |
"Neuroplasticity refers to the brain’s ability to modify its connections and function in response to experience. This experience-dependent plasticity is necessary for the acquisition of new abilities during early development or in adult life, and plays a crucial role in recovery after a neurological injury. During early developmental epochs known as critical periods (CPs), passive experience alone can have profound and long-lasting effects in cortical sensory representations. In contrast, plasticity in the adult brain occurs almost exclusively in the context of perceptual learning (PL); i.e., the process whereby attention and repetition lead to long-lasting improvements in stimulus detection or sensory discrimination.Whether it occurs as a result of passive experience, PL, or other experimental interventions, cortical plasticity ultimately entails a change in activity patterns driven by a shift in the local levels of excitation and inhibition. And although cortical inhibitory interneurons constitute a clear minority compared to the number of excitatory neurons, they are instrumental in regulating both juvenile and adult experience-dependent plasticity. This thesis consists of three experimental studies that addressed critical and interrelated knowledge gaps regarding the inhibitory regulating mechanisms of experience-dependent plasticity, both in the context of changes in the environment and during PL. Using the rat primary auditory cortex (A1) as a model, we combined electrophysiological, anatomical, chemogenetic, and behavioral methodologies to address each study’s main hypotheses. In the first study we examined the role of inhibition in A1 plasticity across the lifespan. We found that reduced cortical inhibition in older adults was associated with an increased but poorly regulated plasticity when compared to younger adults. In older brains, however, changes elicited by auditory stimulation and training were rapidly lost, suggesting that such increased plasticity might be detrimental, as the older brains were unable to consolidate these changes. Importantly, increasing inhibition artificially with clinically available drugs restored the stability of sensory representations and improved the retention of plastic changes associated with PL.In the second study, we turned our attention to parvalbumin-positive (PV+) cells, the most common type of inhibitory neurons in the brain. Bidirectional manipulation of PV+ cell activity affected neuronal spectral and sound intensity selectivity, and, in the case of PV+ interneuron inactivation, was mirrored by anatomical changes in PV and associated perineuronal net expression. In addition, we showed that the inactivation of PV+ interneurons is sufficient to reinstate CP plasticity in the adult auditory cortex. In the third study, we investigated the role of PV+ cells in auditory PL. As previously reported in other cortical areas, training was associated with a transient downregulation of PV expression during early stages of training. We then examined the effects of prolonged PV+ cell manipulation throughout the training period. Our results suggest that, although reduced PV+ cell function may facilitate early training-related modifications in cortical circuits, a subsequent increase in PV+ cell activity is needed to prevent further plastic changes and consolidate learning. Taken together, our findings underscore the importance of sustained inhibitory neurotransmission in ensuring high fidelity discrimination of sensory inputs and in maintaining the stability of sensory representations. Our behavioral studies further suggest that such stability is necessary for the consolidation of complex skills that are built on basic sensory representations. Finally, the experimental work presented in this thesis also highlights the potential of pharmacological and chemogenetic approaches for harnessing cortical plasticity with the ultimate goal of aiding recovery from brain injury or disease"--
| Author | : Thomas N. Parks |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 344 |
| Release | : 2004-08-27 |
| Genre | : Medical |
| ISBN | : 9780387209869 |
The auditory system has a remarkable ability to adjust to an ever-changing environment. The six review chapters that comprise Plasticity of the Central Auditory System cover a spectrum of issues concerning this ability to adapt, defined by the widely applicable term "plasticity". With chapters focusing on the development of the cochlear nucleus, the mammalian superior olivary complex, plasticity in binaural hearing, plasticity in the auditory cortex, neural plasticity in bird songs, and plasticity in the insect auditory system, this volume represents much of the most current research in this field. The volume is thorough enough to stand alone, but is closely related a previous SHAR volume, Development of the Auditory System (Volume 9) by Rubel, Popper, and Fay. The book fully addresses the difficulties, challenges, and complexities of this topic as it applies to the auditory development of a wide variety of species.
| Author | : Jeffery A. Winer |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 711 |
| Release | : 2010-12-02 |
| Genre | : Science |
| ISBN | : 1441900748 |
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 | : Daniel Philip Knudsen |
| Publisher | : |
| Total Pages | : 111 |
| Release | : 2013 |
| Genre | : |
| ISBN | : 9781303175633 |
The brain's representation of the auditory world is not static, but changes based on an animal's history and current goals. We explored experience-dependent changes in both behavioral and neural representations of behaviorally relevant auditory stimuli in the caudal a secondary auditory fore brainregion, in European starlings. To accomplish this, we first designed and built a system that facilitated simultaneous neural and behavioral recording, allowing--for the first time--neural responses to be recorded while birds performed auditory-mediated operant tasks. We found that when birds were engaged in an auditory task, neurons had more information in their stimulus-driven firing rates about the task-relevant stimulus classes than when birds were not engaged in the task. We also trained birds to quickly learn novel stimulus classifications and showed that neural responses change over the course of learning. For most neurons, stimulus-driven neural responses decreased with learning, and they did so most strongly for the newly learned stimuli. We suggest that these effects may be due in part to stimulus-specific adaptation, and its modulation by behavioral state. We also observed the formation of task-dependent firing rate modulation with learning. These results highlight the plasticity of the avian auditory system, and further our understanding of the way that nervous systems adapt to the changing environment and behavioral goals of an organism.
| Author | : Jan Schnupp |
| Publisher | : MIT Press |
| Total Pages | : 367 |
| Release | : 2012-08-17 |
| Genre | : Medical |
| ISBN | : 0262518023 |
An integrated overview of hearing and the interplay of physical, biological, and psychological processes underlying it. Every time we listen—to speech, to music, to footsteps approaching or retreating—our auditory perception is the result of a long chain of diverse and intricate processes that unfold within the source of the sound itself, in the air, in our ears, and, most of all, in our brains. Hearing is an "everyday miracle" that, despite its staggering complexity, seems effortless. This book offers an integrated account of hearing in terms of the neural processes that take place in different parts of the auditory system. Because hearing results from the interplay of so many physical, biological, and psychological processes, the book pulls together the different aspects of hearing—including acoustics, the mathematics of signal processing, the physiology of the ear and central auditory pathways, psychoacoustics, speech, and music—into a coherent whole.
| Author | : Srikanth Reddy Damera |
| Publisher | : |
| Total Pages | : 126 |
| Release | : 2021 |
| Genre | : Neurosciences |
| ISBN | : |
The auditory cortical system, like the visual cortical system, is thought to be organized into a dual-stream architecture consisting of an anterior ventral and a posterior dorsal stream. Under this framework, the anterior ventral stream (also known as the “what” pathway) is specialized for recognizing auditory “objects,” such as spoken words. Despite growing evidence that the anterior ventral stream is organized along a simple-to-complex hierarchy, it is still controversial whether a putative auditory lexicon for words exists and, if so, where it is located. Using an fMRI rapid adaptation experiment, inspired by prior work on visual word recognition, we found evidence that neuronal populations in the left anterior superior temporal gyrus (aSTG) are tightly tuned to individual auditory real words (RWs). In contrast, we found evidence that novel untrained auditory pseudowords (UTPWs) weakly engaged more broadly tuned neurons in this region. This is consistent with a two-stage model of category learning which predicts that auditory lexical representations develop in high-level sensory cortices through experience-dependent refinement of neuronal tuning. Also consistent with this model, we found that neuronal populations in the inferior frontal gyrus (the second stage) are also tuned to individual RWs. To directly test this hypothesis, we performed another experiment in which subjects were trained to recognize previously novel pseudowords (UTPWs). We then compared the selectivity of the aSTG to these pseudowords before and after training. This revealed that neuronal populations in this region were now tightly tuned to trained pseudowords (TPWs) but not UTPWs. In addition, we found evidence that neuronal populations in the left pre-motor cortex are tuned to individual RWs. This raises the possibility that an auditory speech production lexicon may also develop in the auditory dorsal stream.
| Author | : David R. Moore |
| Publisher | : Oxford University Press, USA |
| Total Pages | : 592 |
| Release | : 2010-01-21 |
| Genre | : Medical |
| ISBN | : 0199233284 |
Volume 1: The Ear (edited by Paul Fuchs) Volume 2: The Auditory Brain (edited by Alan Palmer and Adrian Rees) Volume 3: Hearing (edited by Chris Plack) Auditory science is one of the fastest growing areas of biomedical research. There are now around 10,000 researchers in auditory science, and ten times that number working in allied professions. This growth is attributable to several major developments: Research on the inner ear has shown that elaborate systems of mechanical, transduction and neural processes serve to improve sensitivity, sharpen frequency tuning, and modulate response of the ear to sound. Most recently, the molecular machinery underlying these phenomena has been explored and described in detail. The development, maintenance, and repair of the ear are also subjects of contemporary interest at the molecular level, as is the genetics of hearing disorders due to cochlear malfunctions.
