Thesis (M.S.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / There are two types of extracellular fluid in the cochlea: the endolymph of the scala media and the perilymph of the scala vestibuli and scala tympani. Cochlear endolymph and perilymph have different compositions, and the concentration gradient of solutes across the cochlear partition is actively maintained in vivo. In experiments involving fresh cochleas that have been dissected to allow access to the cochlear partition, the cochlea is generally placed in a single medium that aims to nourish the cochlear cells. However, the dissection usually disrupts the separation of endolymph and perilymph across the organ of Corti, the organ in the cochlear partition that contains the auditory sensory cells. Separating the fluids across the cochlear partition during experiments involving dissected cochleas would allow for more physiologically relevant observations to be made. This work was aimed at creating a two-chambered device for holding excised Mongolian gerbil (Meriones unguiculatus) cochlear preparations during in vitro electrical stimulation experiments. Primarily, this device creates experimental conditions that more closely mimic the in vivo physiologic conditions found within the gerbil cochlea by isolating the endolymph medium and perilymph medium bathing the opposing surfaces of the organ of Corti. The device also provides a means to electrically stimulate the organ of Corti and allows for imaging of the response to stimulation. The ability of the device to seal endolymph medium from perilymph medium is shown via electrical resistance measurements between the chambers. The imaging of hair cell motion during electrical stimulation is also demonstrated. / 2031-01-02

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.

Thesis (Ph. D.)--University of Washington, 1991. / Vita. Includes bibliographical references (leaves [106]-116).

Thesis (B.Sc)--University of Hong Kong, 2002. / "A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, May 10, 2002." Also available in print.

No description available.

[Truncated abstract] One of the problems in researching tinnitus is that it has often been assumed that the physiological mechanisms underlying the tinnitus percept cannot be objectively measured. Nonetheless, it is generally accepted that the percept results from altered spontaneous neural activity at some site along the auditory pathway, although it is still debated whether it is produced by: synchronisation of activity of adjacent neurones; a change in the temporal pattern of activity of individual neurones; or an increase in the spontaneous firing rate per se. Similarly, it is possible that the recently coined “auditory neuropathy” is produced by under-firing of the primary afferent synapse, although several other mechanisms can also produce the symptoms described by this disorder (normal cochlear mechanical function but absent, or abnormal, synchronous neural firing arising from the cochlea and auditory brainstem, known as the auditory brainstem response, or ABR). Despite an absent ABR, some subjects can detect pure tones at near-normal levels, although their ability to integrate complex sounds, such as speech, is severely degraded in comparison with the pure-tone audiogram. The aim of the following study was to investigate the normal mechanisms underlying neural firing at the primary afferent synapse, and its regulation, to determine the possible mechanisms underlying over-firing (tinnitus) or under-firing (auditory neuropathy) of primary afferent neurones.

Wong Chun Kit. / Thesis submitted in: October 2006. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 73-76). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background and Motivation --- p.1 / Chapter 1.2 --- Objectives --- p.4 / Chapter 1.3 --- Contributions --- p.4 / Chapter 1.4 --- Thesis Outline --- p.5 / Chapter 2 --- Digital Signal Processing --- p.6 / Chapter 2.1 --- Introduction --- p.6 / Chapter 2.2 --- Discrete-time Signals and Systems --- p.7 / Chapter 2.2.1 --- Discrete-time Signals --- p.7 / Chapter 2.2.2 --- Discrete-time Signal Processing Systems --- p.9 / Chapter 2.2.3 --- Linear Time-Invariant (LTI) Systems --- p.10 / Chapter 2.3 --- Finite Impulse Response (FIR) Filters --- p.13 / Chapter 2.3.1 --- Introduction --- p.13 / Chapter 2.3.2 --- Windowing FIR Filter Design Method --- p.15 / Chapter 2.4 --- Infinite Impulse Response (IIR) Filters --- p.17 / Chapter 2.4.1 --- Introduction --- p.17 / Chapter 2.4.2 --- Bilinear Transform IIR Filter Design Method --- p.18 / Chapter 2.4.3 --- Spectral Transformations of IIR Filters --- p.22 / Chapter 2.5 --- Comparison on FIR and IIR Filters --- p.25 / Chapter 2.6 --- Digital Signal Resampling --- p.26 / Chapter 2.6.1 --- Introduction --- p.26 / Chapter 2.6.2 --- Resampling by Decimation --- p.26 / Chapter 2.6.3 --- Resampling by Interpolation --- p.28 / Chapter 2.6.4 --- Resampling by a Rational Factor --- p.29 / Chapter 2.7 --- Introduction to Dual Fixed-point (DFX) Representation --- p.30 / Chapter 2.8 --- Summary --- p.33 / Chapter 3 --- Lyon and Mead's Cochlea Model --- p.34 / Chapter 3.1 --- Introduction --- p.34 / Chapter 3.2 --- Digital Cochlea Model: Cascaded IIR Filters --- p.37 / Chapter 3.2.1 --- Introduction --- p.37 / Chapter 3.2.2 --- Bandwidth and Centre frequencies --- p.38 / Chapter 3.2.3 --- Zeros and Poles --- p.39 / Chapter 3.3 --- Modifications for Decimated Cochlea Model --- p.41 / Chapter 3.3.1 --- Introduction --- p.41 / Chapter 3.3.2 --- Aliasing Avoidance --- p.42 / Chapter 3.3.3 --- Coefficient Modification after Decimation --- p.43 / Chapter 3.4 --- Summary --- p.47 / Chapter 4 --- System Architecture --- p.48 / Chapter 4.1 --- Introduction --- p.48 / Chapter 4.2 --- Hardware Platform and CAD Tools --- p.48 / Chapter 4.3 --- Sequential Processing Electronic Cochlea --- p.51 / Chapter 4.3.1 --- Pipelining - An Interleaving Scheme --- p.53 / Chapter 4.3.2 --- Decimation in Sequential Processing Electronic Cochlea . --- p.54 / Chapter 4.3.3 --- Multiple Sequential Cores --- p.55 / Chapter 4.3.4 --- Architecture of the DFX Filter Computation Core --- p.55 / Chapter 4.4 --- Summary --- p.60 / Chapter 5 --- Experimental Results --- p.61 / Chapter 5.1 --- Introduction --- p.61 / Chapter 5.2 --- Testing Environment --- p.61 / Chapter 5.3 --- Performance of the Sequential Electronic Cochlea --- p.63 / Chapter 5.3.1 --- Comparisons --- p.63 / Chapter 5.4 --- Summary --- p.69 / Chapter 6 --- Conclusions --- p.70 / Chapter 6.1 --- Future Work --- p.72 / Bibliography --- p.73

No description available.

No description available.