Modeling Binaural Responses in the Auditory Brainstem to Electric Stimulation of the Auditory Nerve PDF Download
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Author: Yoojin Chung
Publisher:
ISBN:
Category :
Languages : en
Pages : 320
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Book Description
Abstract: Bilateral cochlear implants (BiCIs) are becoming more common recently and have been proven to provide improvements in speech perception in noise and sound localization. However, benefits to sound localization for BiCI listening are mainly from the perception of interaural level differences while interaural time difference (ITD) sensitivity is very limited. To help understand this, the current modeling study focused on the following characteristics of neurophysiological data from ITD-sensitive neurons in acutely deafened animal models with BiCIs: (1) rate-limitation of ITD sensitivity to constant-amplitude pulse trains, (2) intensity dependence of ITD sensitivity, and (3) effect of amplitude modulation on ITD sensitivity with high-rate stimulation. A network of model neurons was used to study binaural responses to electrical stimulation. Our working hypothesis was that central auditory processing is normal so that the abnormality in the response to the electric stimulation at the level of the auditory nerve fibers (ANFs) is the source of the limited binaural response. A descriptive model of ANF response to electric stimulation was implemented and used as an input to a network of model neurons in the ascending auditory pathway, up to the inferior colliculus (IC). The result shows that ITD sensitivity depends strongly on the specific configurations of membrane and synaptic parameters for different input stimulation rates. Stronger excitatory synaptic inputs and a faster membrane response are required for the model neurons to be ITD-sensitive at high stimulation rates, both in electric and acoustic stimulation. This raises the possibility of frequency-dependent differences in neural mechanisms of binaural processing; limitations in ITD sensitivity may be due to the mismatch between stimulation rate and cell parameters in ITD-sensitive neurons. The high spike rate and phase-locking at the ANF to electric stimulation changes the rate-ITD tuning at the IC. Amplitude modulation of the high-rate stimulation restores the ongoing ITD sensitivity by effectively reducing the spike rate in the ANF. ITD sensitivity to temporal fine-structure is restored in the model with amplitude-modulated high-rate stimulation, consistent with physiological results. Overall, this study suggests that fine-structure ITD can be delivered to BiCI users with proper processing strategies.
Author: Yoojin Chung
Publisher:
ISBN:
Category :
Languages : en
Pages : 320
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Book Description
Abstract: Bilateral cochlear implants (BiCIs) are becoming more common recently and have been proven to provide improvements in speech perception in noise and sound localization. However, benefits to sound localization for BiCI listening are mainly from the perception of interaural level differences while interaural time difference (ITD) sensitivity is very limited. To help understand this, the current modeling study focused on the following characteristics of neurophysiological data from ITD-sensitive neurons in acutely deafened animal models with BiCIs: (1) rate-limitation of ITD sensitivity to constant-amplitude pulse trains, (2) intensity dependence of ITD sensitivity, and (3) effect of amplitude modulation on ITD sensitivity with high-rate stimulation. A network of model neurons was used to study binaural responses to electrical stimulation. Our working hypothesis was that central auditory processing is normal so that the abnormality in the response to the electric stimulation at the level of the auditory nerve fibers (ANFs) is the source of the limited binaural response. A descriptive model of ANF response to electric stimulation was implemented and used as an input to a network of model neurons in the ascending auditory pathway, up to the inferior colliculus (IC). The result shows that ITD sensitivity depends strongly on the specific configurations of membrane and synaptic parameters for different input stimulation rates. Stronger excitatory synaptic inputs and a faster membrane response are required for the model neurons to be ITD-sensitive at high stimulation rates, both in electric and acoustic stimulation. This raises the possibility of frequency-dependent differences in neural mechanisms of binaural processing; limitations in ITD sensitivity may be due to the mismatch between stimulation rate and cell parameters in ITD-sensitive neurons. The high spike rate and phase-locking at the ANF to electric stimulation changes the rate-ITD tuning at the IC. Amplitude modulation of the high-rate stimulation restores the ongoing ITD sensitivity by effectively reducing the spike rate in the ANF. ITD sensitivity to temporal fine-structure is restored in the model with amplitude-modulated high-rate stimulation, consistent with physiological results. Overall, this study suggests that fine-structure ITD can be delivered to BiCI users with proper processing strategies.
Author: Konstantina M. Trbovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 176
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Author: Paul Alfred Lobaugh
Publisher:
ISBN:
Category : Auditory evoked response
Languages : en
Pages : 272
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 54
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Author: Ryuji Suzuki (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 52
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Book Description
Cochlear nucleus (CN), the exclusive destination of the auditory nerve, is the gateway for all central processing of auditory information. The CN comprises three major subdivisions: anteroventral, posteroventral and dorsal (AVCN, PVCN and DCN, respectively), each of which contains anatomically and physiologically distinct neurons projecting onto different targets. This research used focal electric stimulation of small, confined parts of the CN in anesthetized guinea pigs to resolve the roles of the CN divisions, in two contexts. Part i explored the effect of stimulation on the gross neural potential (electrically evoked auditory brainstem response, EABR). In AVCN and PVCN away from the 8th nerve fibers entering the brainstem, stimulation consistently evoked waveforms comprising 3 waves, suggesting a diffuse distribution of cellular generator of the EABR. On the other hand, in vestibular structures (vestibular nerve root and Scarpa's ganglion), the characteristic waveform comprised only two waves. Stimulation of multiple neural structures, as seen with higher stimulus levels or stimulation in auditory nerve root area generally produced more complex and variable waveforms. Part 2 explored the effects of stimulation on the activation of one type of auditory reflex, medial olivocochlear (MOC) reflex. The reflex was monitored through its effects on distortion product otoacoustic emission (DPOAE). The MOC reflex was activated bilaterally by stimulating PVCN or AVCN shell, but not AVCN core. These results suggest that there are two groups of MOC interneurons in specific parts of CN.
Author: Ruth Y. Litovsky
Publisher: Springer Nature
ISBN: 3030571009
Category : Medical
Languages : en
Pages : 425
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Book Description
The field of Binaural Hearing involves studies of auditory perception, physiology, and modeling, including normal and abnormal aspects of the system. Binaural processes involved in both sound localization and speech unmasking have gained a broader interest and have received growing attention in the published literature. The field has undergone some significant changes. There is now a much richer understanding of the many aspects that comprising binaural processing, its role in development, and in success and limitations of hearing-aid and cochlear-implant users. The goal of this volume is to provide an up-to-date reference on the developments and novel ideas in the field of binaural hearing. The primary readership for the volume is expected to be academic specialists in the diverse fields that connect with psychoacoustics, neuroscience, engineering, psychology, audiology, and cochlear implants. This volume will serve as an important resource by way of introduction to the field, in particular for graduate students, postdoctoral scholars, the faculty who train them and clinicians.
Author: Joan Lynch Luckett
Publisher:
ISBN:
Category :
Languages : en
Pages : 114
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Author: Gangesh Kumar Ganesan
Publisher:
ISBN:
Category : Acoustic nerve
Languages : en
Pages : 98
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Author: Michaël Charles Chalom Slama
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Auditory brainstem implants (ABIs) help provide some hearing to patients with non-functional auditory nerves or ossified cochleae. ABIs bypass the cochlea and electrically stimulate the surface of the cochlear nucleus (CN). Performance of ABI users in speech reception tasks is usually poor. One of the possible explanations for their limited performance is the poor spatial selectivity of electrical stimulation that limits frequency resolution. In this project, we show that spatial selectivity of electrical stimulation was usually poor in a rat model, as stimulation in one point of the CN surface led to activation of most of the tonotopic axis in the inferior colliculus (IC). These results point to the need for new stimulation strategies to improve frequency representation in the central auditory system of ABI users. An optogenetic approach is promising, as light may be more easily focused than electrical current. To test the feasibility of optogenetic control of the CN, we transfected the CN of mice with AAV2/8-Channelrhodopsin-2 (ChR2). We found a significant increase in activity in IC and primary auditory cortex during blue light stimulation in mice with successful ChR2 expression in the CN. Overall, these results lay the groundwork for a new generation opto-electronic ABI.
Author: Ray Meddis
Publisher: Springer Science & Business Media
ISBN: 1441959343
Category : Medical
Languages : en
Pages : 290
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Book Description
The Springer Handbook of Auditory Research presents a series of comprehensive and synthetic reviews of the fundamental topics in modern auditory research. The v- umes are aimed at all individuals with interests in hearing research including advanced graduate students, post-doctoral researchers, and clinical investigators. The volumes are intended to introduce new investigators to important aspects of hearing science and to help established investigators to better understand the fundamental theories and data in fields of hearing that they may not normally follow closely. Each volume presents a particular topic comprehensively, and each serves as a synthetic overview and guide to the literature. As such, the chapters present neither exhaustive data reviews nor original research that has not yet appeared in pe- reviewed journals. The volumes focus on topics that have developed a solid data and conceptual foundation rather than on those for which a literature is only beg- ning to develop. New research areas will be covered on a timely basis in the series as they begin to mature.
