An Integrated Psychoacoustic And High-field FMRI Study Of Auditory Temporal Processsing Dysfunction In Schiophrenia.
Funder
National Health and Medical Research Council
Funding Amount
$306,000.00
Summary
This research seeks to improve our understanding of the causes of brain dysfunction in schizophrenia. This chronic and debilitating psychiatric disorder is usually accompanied by dramatic symptoms such as hallucinations, delusions, paranoia and disordered patterns of thinking. Based on our interpretation of evidence from a number of fields of schizophrenia research we suspect that the brain dysfunction in schizophrenia may not in the brain areas responsible for those dramatic symptoms but occurs ....This research seeks to improve our understanding of the causes of brain dysfunction in schizophrenia. This chronic and debilitating psychiatric disorder is usually accompanied by dramatic symptoms such as hallucinations, delusions, paranoia and disordered patterns of thinking. Based on our interpretation of evidence from a number of fields of schizophrenia research we suspect that the brain dysfunction in schizophrenia may not in the brain areas responsible for those dramatic symptoms but occurs initially in the very basic sensory regions of the brain. These regions can be thought of as providing the building blocks of our perceptions, that ultimately allow us to see, hear, smell and feel. Our previous research shows that people with schizophrenia have a very specific problem in the way that they perceive sounds. Using measures of brain activity, people with schizophrenia show consistent evidence that their brains do not process some of the timing information contained in sound. This is not the same as saying that people with schizophrenia are deaf, the deficits we see are much more subtle. It's a bit like the chaos theory analogy of a butterfly fluttering in Brazil and causing a typhoon in China. We think that very small alterations in brain activity in the initial stages of sensory processing can cascade through successively more complex stages of the brain, eventually creating the psychotic storm that becomes evident as the primary symptoms of schizophrenia. The brain regions we are interested in are located down at the base of the brain, in the brainstem, and it is only recently that the technology and methods of analysis we need to look at this activity have been developed. In this research we will be using functional magnetic resonance imaging and sophisticated hearing tests to examine whether these brain regions show the alterations we expect. If so, this will mean that the brain dysfunction in schizophrenia is quite different to what is currently believed.Read moreRead less
Extraction Of Key Features Of Natural Speech By Ventral Cochlear Nucleus Neurons
Funder
National Health and Medical Research Council
Funding Amount
$225,330.00
Summary
Little is known about how speech is processed and transformed by the central auditory pathway, and how the critical temporal and spectral features that identify a speech sound segment (a phoneme) are extracted. To date, most studies have approached this issue by using synthetic speech and examined the responses of the peripheral auditory nerve only. The aim of this study is to examine how important features of naturally-spoken speech are encoded by the cochlear nucleus (CN) - the first station i ....Little is known about how speech is processed and transformed by the central auditory pathway, and how the critical temporal and spectral features that identify a speech sound segment (a phoneme) are extracted. To date, most studies have approached this issue by using synthetic speech and examined the responses of the peripheral auditory nerve only. The aim of this study is to examine how important features of naturally-spoken speech are encoded by the cochlear nucleus (CN) - the first station in the auditory pathway located in the brainstem. The CN is a complex of different cell types that have the capacity to transmit, transform, and encode complex acoustic information in different ways. The proposed experiments involve recording the bioelectrical signal from single CN cells in anaesthetised rats while presenting naturally-spoken syllables, both in quiet and in the presence of noise. It is important to examine what happens to the neural responses in the latter condition, because all animals must cope with the problem of extracting important signals from background noise. While noise clearly interferes with the perception of another sound, the auditory system is in fact quite good at extracting signals in the presence of noise. This is well demonstrated by our ability to understand speech in the presence of quite high noise levels. This ability is severely degraded in the hearing impaired. Thus, one of the aims of this study is to examine the mechanisms and limits of the CN's ability to encode speech in a noisy background. A greater understanding of the mechanisms the nervous system uses to extract critical features of speech will not only build on our knowledge of auditory brainstem processes, but may also provide clues to improving processing strategies for cochlear implants.Read moreRead less
The key to how the brain works lies in its capacity to modify the strength of its connections. During development, input to the brain from our sensory organs shapes the properties of synaptic contacts and target neurons. This project is aimed at understanding the pathways in the brain related to our sense of hearing, and discovering what is different about these pathways in congenital deafness, where the brain does not receive the appropriate signals during development.
Early Indicators Of Noise Injury: Are Decreased Auditory Processing Skills Evident In Noise-exposed Adults Prior To Diagnosis Of Hearing Loss?
Funder
National Health and Medical Research Council
Funding Amount
$367,605.00
Summary
Recent research indicates that noise-exposed individuals with similar hearing thresholds to non-noise exposed counterparts are more likely to have diminished temporal and spectral auditory processing abilities. This research aims to determine the relationship between noise exposure levels and auditory processing difficulties; the influence of musical training in ameliorating these difficulties; and a neurological model of causation, operation and possible remediation of these difficulties.
Intrinsic Hearing Protection Mechanisms: A Pathway To Prevention Of Noise-induced Hearing Loss
Funder
National Health and Medical Research Council
Funding Amount
$625,900.00
Summary
Noise-induced hearing loss (NIHL) is a significant contributor to the total burden of disease. We recently determined that when the ear is exposed to sustained noise, the cochlea is protected from damage by activation of a specific (P2X2) receptor, evident as reversible hearing adaptation. This study will determine the downstream signalling from this receptor. This will support assessment of vulnerability to NIHL and contribute to development of hearing therapeutics.
Cochlear Type II Neurons In Contralateral Suppression
Funder
National Health and Medical Research Council
Funding Amount
$459,434.00
Summary
Sound in one ear affects hearing in the other ear. This contralateral suppression is important for hearing attention and protection from noise damage. We will test the hypothesis that cochlear type II sensory neurons provide the sensory input for this process using models where neuronal development is altered, or the neurons are removed. The study addresses hearing disability in society, facilitating cochlear prosthesis development and the understanding of hearing loss.
The brain exerts a restraining influence over the heartbeat via the vagus nerves. This is known as cardiac vagal ‘tone’. It is strong when we are healthy but weak when we are sick. It has a positive influence on the health of the heart and perhaps the body generally. Vagal tone comes from the brain but, despite over 150 years’ research, nobody knows exactly where. Using a novel technique, we can track down its origins. This important basic knowledge may lead to ways to improve health.
Auditory Processing Deficits In Specific Language Impairment And Specific Reading Disability:Their Effects And Treatment
Funder
National Health and Medical Research Council
Funding Amount
$314,250.00
Summary
One possible cause of specific language impairment (SLI) and specific reading disability (SRD; commonly known as dyslexia) is an inability to discriminate between sounds. Such an impairment could affect the ability to discriminate between simple speech sounds (phonemes) which are the basic building blocks for developing spoken language and reading skills. How many children with SLI or SRD have poor sound discrimination? What pattern of spoken language and reading impairments do these children ha ....One possible cause of specific language impairment (SLI) and specific reading disability (SRD; commonly known as dyslexia) is an inability to discriminate between sounds. Such an impairment could affect the ability to discriminate between simple speech sounds (phonemes) which are the basic building blocks for developing spoken language and reading skills. How many children with SLI or SRD have poor sound discrimination? What pattern of spoken language and reading impairments do these children have as a result of this impairment? Can poor sound discrimination be fixed? If it can, does it improve spoken language and reading impairments? And if it does, does it have an immediate effect or does it take some time to make a difference? These are some of the questions that will be addressed by this research. The answers will help us develop a training program that focuses specifically on improving the sound discrimination abilities of children who really need it. This will be a more efficient and inexpensive (if not free) than the Fast ForWord program that trains multiple non-verbal and verbal processing abilities regardless of whether a child has an impairment in all (or any) of these abilities and is therefore time consuming (approximately 80 hours) and expensive (approximately $AUD2000). The data will also help up better identify the spoken and written language profiles that characterise children who have sound discrimination deficits so we can better predict whether they would benefit from training programs such as Fast ForWord. And the data will tell use whether impaired sound discrimination can be used to predict whether infants might be at risk for later spoken language and reading problems.Read moreRead less