Temporal Processing In The Superior Olivary Complex: Impact Of Deafness And Peripheral Electrical Stimulation Strategies
Funder
National Health and Medical Research Council
Funding Amount
$225,500.00
Summary
The brain can use timing or temporal information to extract the frequency and location of sound. Timing information is coded by the pattern of responses of brain cells that match the period of the sound wave. These responses can be measured as small voltage spikes or action potentials. Integration of these responses from one brain-processing site to another relies on precise (temporally matched) firing among a population of cells that are activated in response to sound. Sound localisation relies ....The brain can use timing or temporal information to extract the frequency and location of sound. Timing information is coded by the pattern of responses of brain cells that match the period of the sound wave. These responses can be measured as small voltage spikes or action potentials. Integration of these responses from one brain-processing site to another relies on precise (temporally matched) firing among a population of cells that are activated in response to sound. Sound localisation relies on this temporal integration from information coming from both ears. Specifically, the integration of this information relies on the balance of incoming inputs from both ears, which maintains an appropriate time window depending on the location of sound in space. Recent evidence suggests that in deafness this process of integration is disrupted which may be possibly due to an inability to regulate the coherent activation of cells. This has implications for cochlear implant users whose ability to process temporal information is compromised by a loss of temporal coding ability resulting from prior deafness. In this project we will measure voltage changes occurring inside cells of the superior olivary complex, which contains a group of structures that integrate input from both ears. We will examine the ability of these cells to process temporal information in normal and deafened conditions. This study will lead not only to an understanding of basic mechanisms for auditory coding but also to improved electrical stimulation strategies for patients with cochlear implants.Read moreRead less
Vestibular Activation In Benign Paroxysmal Positional Vertigo And Superior Semicircular Canal Dehiscence
Funder
National Health and Medical Research Council
Funding Amount
$340,350.00
Summary
Vestibular Activation in Benign Paroxysmal Positional Vertigo and Superior Semicircular Canal Dehiscence The aim of this project is to study the pathological activation of the vestibular system in benign paroxysmal positional vertigo and superior canal dehiscence in order to achieve an improved diagnosis in both conditions and a more effective treatment for benign paroxysmal positional vertigo. These diseases provide unique opportunities to study unilateral activation of an otherwise normal huma ....Vestibular Activation in Benign Paroxysmal Positional Vertigo and Superior Semicircular Canal Dehiscence The aim of this project is to study the pathological activation of the vestibular system in benign paroxysmal positional vertigo and superior canal dehiscence in order to achieve an improved diagnosis in both conditions and a more effective treatment for benign paroxysmal positional vertigo. These diseases provide unique opportunities to study unilateral activation of an otherwise normal human vestibular system. Benign paroxysmal positional vertigo and its variants is prevalent, especially amongst the elderly, as a major cause of dizziness and imbalance. These conditions describe a variety of vestibular lithiasis where free-floating otoconia misplaced in a semicircular canal cause abnormal deflection of the cupula, resulting in activation of the semicircular canal in a vestibular system during changes in gravitational head position. This study endeavours to develop a scientific basis for accurate diagnosis of benign paroxysmal positional vertigo and its variants. Online real-time 3-D recording and vector analysis of the nystagmus could be adapted to a 3-D video-oculography system for a more systematic approach to diagnosis and treatment. Thus, we aim to develop and trial a suitable particle repositioning manoeuvre using a mechanical device as treatment for patients who did not respond to the clinical Epley or Semont manoeuvre. Superior semicircular canal dehiscence permits sound or pressure to abnormally activate the vestibular system. In the superior canal dehiscence study, we seek to develop a more sensitive diagnostic test. If the click-evoked 3-D VOR is due to direct activation of the otoliths, then it offers an avenue to examine otolithic function. Understanding the mechanism of unilateral activation of a normal human vestibular system is important for the development of implantable vestibular prosthesis.Read moreRead less