Responses from Electric Stimulation of Cochlear Nucleus

Responses from Electric Stimulation of Cochlear Nucleus PDF 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.

Responses from Electric Stimulation of Cochlear Nucleus

Responses from Electric Stimulation of Cochlear Nucleus PDF 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.

Cochlear Implants

Cochlear Implants PDF Author: Joseph M. Miller
Publisher: Springer Science & Business Media
ISBN: 1461232562
Category : Medical
Languages : en
Pages : 416

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Book Description
This volume describes a new direction in technological and biomedical developments for profoundly deaf individuals. The first section covers topics of tissue characteristics, such as responses to electrical stimulation and computer modelling of cochlea currents. Perception of acoustic signals, responses and behavioral pattern as well as psychophysical aspects are treated in the second part. Part III is addressed to perspectives and challenges of encoding schemes. Reports on studies of acoustic and electrical encoding of temporal information, speech features with cochlear implants as well as psychophysical and speech perceptual studies will allow further strategies for cochlea implants.

Responses of Dorsal Cochlear Nucleus Single Units to Acoustic and Electrical Stimulation of the Auditory Nerve

Responses of Dorsal Cochlear Nucleus Single Units to Acoustic and Electrical Stimulation of the Auditory Nerve PDF Author: Stephen John O'Leary
Publisher:
ISBN:
Category : Acoustic nerve
Languages : en
Pages : 426

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Electric Responses of Individual Nerve Elements in Cochlear Nucleus to Sound Stimulation (guinea Pig)

Electric Responses of Individual Nerve Elements in Cochlear Nucleus to Sound Stimulation (guinea Pig) PDF Author: Ichiji Tasaki
Publisher:
ISBN:
Category :
Languages : en
Pages : 158

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Book Description


Auditory Prostheses

Auditory Prostheses PDF Author: Fan-Gang Zeng
Publisher: Springer Science & Business Media
ISBN: 1441994343
Category : Medical
Languages : en
Pages : 397

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Book Description
Cochlear implants are currently the standard treatment for profound sensorineural hearing loss. In the last decade, advances in auditory science and technology have not only greatly expanded the utility of electric stimulation to other parts of the auditory nervous system in addition to the cochlea, but have also demonstrated drastic changes in the brain in responses to electric stimulation, including changes in language development and music perception. Volume 20 of SHAR focused on basic science and technology underlying the cochlear implant. However, due to the newness of the ideas and technology, the volume did not cover any emerging applications such as bilateral cochlear implants, combined acoustic-electric stimulation, and other types of auditory prostheses, nor did it review brain plasticity in responses to electric stimulation and its perceptual and language consequences. This proposed volume takes off from Volume 20, and expands the examination of implants into new and highly exciting areas. This edited book starts with an overview and introduction by Dr. Fan-Gang Zeng. Chapters 2-9 cover technological development and the advances in treating the full spectrum of ear disorders in the last ten years. Chapters 10-15 discuss brain responses to electric stimulation and their perceptual impact. This volume is particularly exciting because there have been quantum leap from the traditional technology discussed in Volume 20. Thus, this volume is timely and will be of real importance to the SHAR audience.

Using Electrical Stimulation Responses to Understand Cochlear Implant Status

Using Electrical Stimulation Responses to Understand Cochlear Implant Status PDF Author: Simone De Rijk
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Chronic Electrical Stimulation by a Cochlear Implant Prevents Degeneration of Spiral Ganglion Neurons and Induces Temporal and Spatial Plasticity in the Mature Deafened Auditory System

Chronic Electrical Stimulation by a Cochlear Implant Prevents Degeneration of Spiral Ganglion Neurons and Induces Temporal and Spatial Plasticity in the Mature Deafened Auditory System PDF Author: Charlotte M. Moore
Publisher:
ISBN:
Category : Auditory pathways
Languages : en
Pages : 312

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Selective Stimulation and Measurement in the Cochlear Nucleus With the Spike Microelectrode Array

Selective Stimulation and Measurement in the Cochlear Nucleus With the Spike Microelectrode Array PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Current prosthetic devices to restore hearing sense of patients with bilateral acoustic neuromas aren't always effective, because we don't have sufficient knowledge of the auditory pathways and the Cochlear Nucleus (CN) functions to stimulate the Cochlear Nucleus functionally. Our goals are to enhance our understanding of such functions and to develop effective stimulating strategies of the CN. In this paper, we fabricate the spike microelectrode array with 16-sites in 1.3mm-square area for stimulation and measurement of the CN and show its feasibility through rats' experiments. In the experiments, spatiotemporal responses in the CN are recorded with the electrode. Electrical stimulation at different sites with different current amplitudes exhibits different spatiotemporal patterns on the Auditory Cortex. These results will provide useful information to study the auditory pathways and the CN functions and to develop stimulating strategies.

Electrical Responses of Neural Units in the Anteroventral Cochlear Nucleus of the Cat

Electrical Responses of Neural Units in the Anteroventral Cochlear Nucleus of the Cat PDF Author: Terrance Raymond Bourk
Publisher:
ISBN:
Category : Cats
Languages : en
Pages : 772

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Matching the Neural Adaptation in the Rat Ventral Cochlear Nucleus Produced by Artificial (electric) and Acoustic Stimulation of the Cochlea

Matching the Neural Adaptation in the Rat Ventral Cochlear Nucleus Produced by Artificial (electric) and Acoustic Stimulation of the Cochlea PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
To investigate neural adaptive properties, near-field evoked potentials were recorded from a chronically implanted electrode in the ventral cochlear nucleus in awake Long-Evans rats exposed to acoustic stimuli or receiving intracochlear electric stimulation. Stimuli were 250-ms trains of repetitive acoustic clicks (10, 30 and 50 dB SPL) or biphasic electric pulses (30, 50 and 70 μA) with intratrain pulse rates ranging from 100 to 1000 pulses per second (pps). The amplitude of the first negative (N1) to positive (P1) component of the average evoked potentials was measured for each consecutive individual pulse in the train. While a progressive exponential decrease in N1-P1 amplitude was observed as a function of the position of the pulse within the train for both types of stimulation, the decrement of electric responses (adaptive pattern) was substantially less prominent than that observed for acoustic stimuli. Based on this difference, the present work was extended by modifying electric stimuli in order to try to restore normal adaptation phenomena. The results suggest the feasibility of mimicking acoustic adaptation by stimulation with exponentially decreasing electric pulse trains, which may be clinically applicable in the auditory implant field.