NEURAL MODULATION OF HEARING LOSSES INDUCED BY LOUD SOUND
Funder
National Health and Medical Research Council
Funding Amount
$290,500.00
Summary
Loud sounds, from occupational and recreational sources, are the most common threat to hearing and can result in temporary hearing losses (as might be experienced after an evening at a noisy pub or concert) or permanent hearing losses (after prolonged or multiple loud sounds, as for example in a noisy work environment). Noise reduction programs are either not always possible or effectively applied. A parallel strategy is the study of biological mechanisms that may ameliorate hearing damage, with ....Loud sounds, from occupational and recreational sources, are the most common threat to hearing and can result in temporary hearing losses (as might be experienced after an evening at a noisy pub or concert) or permanent hearing losses (after prolonged or multiple loud sounds, as for example in a noisy work environment). Noise reduction programs are either not always possible or effectively applied. A parallel strategy is the study of biological mechanisms that may ameliorate hearing damage, with a view to optimising such mechanisms. I propose to build on seminal Australian work to examine how one such system, nerves from the brain to the inner ear (the site of most damage from loud sounds), modulates hearing losses caused by loud sounds. Early studies indicated these nerves could protect from damage induced by short-lasting loud sound and this has led to international interest in functional applications of such protection to reduce hearing damage suffered by humans. However, my recent work indicates the nerves exert complex protective and exacerbative effects to loud sounds similar to common trauma or occurring under conditions similar to common trauma. They even exacerbate hearing losses due to loud sound, especially when there is an imbalance in hearing sensitivity in the two ears (bilateral) similar to what is common in humans. These findings make it critical that functional application be delayed until the full range of effects exerted by the nerves is understood. I propose to elucidate the novel complex effects of these nerves to loud sound. Specific aims are: (1) To understand effects of these pathways to loud sounds like those encountered by humans, (2) To investigate how chronic imbalanced bilateral hearing sensitivity, like that common in humans, alters effects of the nerves and when they change from being protective to exacerbative, (3) To adduce how an atraumatic sound affects hearing losses due to later loud sound and the role played by these nerves.Read moreRead less
Hearing Protection Conferred By P2X2 Receptor Signaling In The Cochlea
Funder
National Health and Medical Research Council
Funding Amount
$580,019.00
Summary
Hearing loss from noise damage and ageing is the principal sensory disability in our society. This project will determine the contribution of the P2X2 receptor to protection from noise-induced hearing loss. We have found that P2X2 knockout mice have minimal temporary threshold shift. We will investigate the physiological basis for this and determine why this mouse model has greater hearing loss with intense sound and faster age-related hearing loss compared with wildtype controls.
The discoveries made to date and the proposed studies point to an intrinsic role for vitamin D compounds in skin in providing protection from sun damage. As a result of sun exposure, increased concentrations of vitamin D compounds in skin will be generated and this is likely to provide protection against further UV damage, in much the same way as increased pigmentation and increased thickness of the outer layer of skin. Furthermore, the studies are designed to test whether vitamin D compounds wh ....The discoveries made to date and the proposed studies point to an intrinsic role for vitamin D compounds in skin in providing protection from sun damage. As a result of sun exposure, increased concentrations of vitamin D compounds in skin will be generated and this is likely to provide protection against further UV damage, in much the same way as increased pigmentation and increased thickness of the outer layer of skin. Furthermore, the studies are designed to test whether vitamin D compounds which have minimal effects on serum calcium, could nevertheless be used topically in association with a sunscreen or moisturizer to add to sun protection. As Australia has the highest skin cancer rates in the world, this would be of significant health and economic value.Read moreRead less
Mechanisms Of Photoprotection By Vitamin D And Analogs
Funder
National Health and Medical Research Council
Funding Amount
$438,186.00
Summary
Our discoveries have clearly shown that vitamin D compounds produced in skin due to UV exposure, have a role in protecting skin from further UV damage. The studies are designed to further examine the mechanism of this photoprotective effect, as it appears to be novel. This will aid in the developmentof agents, which could be used as an after-sun lotion to gain some protection. As Australia has the highest skin cancer rates in the world, this would be of significant health and economic value.
Development Of Executive Functions In Children With Frontal Lobe Lesions
Funder
National Health and Medical Research Council
Funding Amount
$160,379.00
Summary
Executive functions (EF), refer to the ability to problem solve, think flexibly and in abstract terms and pay attention. EFs are essential for managing daily life activities. The frontal lobes of the brain are believed be important in coordinating EFs. In childhood, frontal areas are developing rapidly and damage may affect ongoing development due to impairments in a child's capacity to function normally within their environment, interfering with adaptive functions such as new learning and reaso ....Executive functions (EF), refer to the ability to problem solve, think flexibly and in abstract terms and pay attention. EFs are essential for managing daily life activities. The frontal lobes of the brain are believed be important in coordinating EFs. In childhood, frontal areas are developing rapidly and damage may affect ongoing development due to impairments in a child's capacity to function normally within their environment, interfering with adaptive functions such as new learning and reasoning. Executive dysfunction in children manifests as disorganisation, impulsivity, inattention and inappropriate behaviour. Such problems are often masked in early chilhood, due to highly structured environments and support of parents and care-givers in day-to-day activities. However, as children mature, expectations of indepence increase and executive deficits become more apparent (ie. child 'grows into' these problems). Appropriate treatment and management is dependent on (i) improvement in early identification of patients at risk for such sequelae; (ii) establishing long-term consequences of executive deficits to ongoing development. This research aims to advance our understanding of EFs and their development through childhood, both in healthy children and children with cerebral lesions to regions believed to subsume EFs(ie the frontal lobes). While anecdotal case data is available, to our knowledge, no other study has attempted to do this using a longitudinal group design. Specific predictions include; (i) Children with frontal lobe damage will perform more poorly on EF measures, in comparison to children with damage to other cerebral areas and healthy children; (ii) Children with frontal lobe damage will show increasing deficits on EF tasks over time, reflecting an inability to acquire executive skills in the expected time frame, when compared with children with localised damage to cerebral areas excluding the frontal lobes, and healthy children.Read moreRead less
Neural Coding Of A Cue To Auditory Space, In Noisy Environments
Funder
National Health and Medical Research Council
Funding Amount
$180,160.00
Summary
GENERAL BACKGROUND : Our ability to determine where a sound is coming from (localization ability) is severely disrupted when the environment is noisy. This affects our abilities at many ordinary tasks, such as keeping up a conversation in a noisy background, and also in other critical tasks (eg., in following warning signals in a noisy factory environment). In people who have some hearing loss, even if only partial deafness, localization ability is disrupted even when there is no noise in the ba ....GENERAL BACKGROUND : Our ability to determine where a sound is coming from (localization ability) is severely disrupted when the environment is noisy. This affects our abilities at many ordinary tasks, such as keeping up a conversation in a noisy background, and also in other critical tasks (eg., in following warning signals in a noisy factory environment). In people who have some hearing loss, even if only partial deafness, localization ability is disrupted even when there is no noise in the background, and is even more severely disrupted when the environment is noisy. SCIENTIFIC BACKGROUND : Our localization ability depends on the way neurons in the brain code the position of a source of sound we wish to detect. From studies in animals we know a lot about the way in which neurons do this coding in silence. However, we know almost nothing about how this coding is affected by a noisy background. Further, we know absolutely nothing about how this coding, whether in silence or when there is noise, is affected when there is also a hearing loss. SIGNIFICANCE : If we are to understand the effects of hearing losses on coding of the location of a sound signal we need to know first how noise affects the coding in cases of normal hearing. This project aims to gain that information. I will then extend this to studying the detailed basis of these effects, ie., exactly what mechanisms are affected in the neurons. Then I will determine how noise from different positions affects the coding of signal sounds at differnt positions. These data will provide us the essential base from which we can, later, go on to study how noise affects coding by neurons of the location of a signal. I plan to increase the value of the current study by developing, from the data gained in the studies in animals, computer-based models that will allow us to predict how coding of sound signal location is affected by hearing loss, and how this is exacerbated by noisy environments.Read moreRead less
Potential For Creatine Or Melatonin As Dietary Supplements In Pregnancy To Prevent Perinatal Brain Damage
Funder
National Health and Medical Research Council
Funding Amount
$483,217.00
Summary
Brain damage in the newborn - particularly in prematurely born infants - remains a significant health problem. At present there are very few treatments that can be used to minimize damage when it becomes apparent in the newborn, and none that can be used PROSPECTIVELYduring pregnancy to protect the developing brain from damage. The most likely cause of damage to the fetal brain during pregnancy or at birth is global ASPHYXIA, either by itself or in association with other problems of pregnancy su ....Brain damage in the newborn - particularly in prematurely born infants - remains a significant health problem. At present there are very few treatments that can be used to minimize damage when it becomes apparent in the newborn, and none that can be used PROSPECTIVELYduring pregnancy to protect the developing brain from damage. The most likely cause of damage to the fetal brain during pregnancy or at birth is global ASPHYXIA, either by itself or in association with other problems of pregnancy such as infection, preterm birth, or fetal growth retardation. In this project we propose that providing extra amounts of the dietary constituent creatine, or of the hormone melatonin, to the pregnant animal in late gestation, will provide NEUROPROTECTION to the developing brain in the face of an asphyxial challenge that otherwise causes damage. We will use pregnant sheep to investigate the effects of asphyxia in utero on the fetal brain using techniques that allow us to monitor metabolic changes within the brain in real time. In addition, we will use the pregnant Spiny Mouse to investigate the effects of birth asphyxia on the postnatal brain structure and behavioral development. We will study groups of animals fed a normal diet, and compare then to animals that receive additional amounts of creatine or melatonin. We expect to determine if either of these treatments have the potential to protect the developing brain from asphyxial damage, and to recommend if similar treatments could be used in pregnant women where the obstetrician suspects the baby's brain is at risk of damage.Read moreRead less