Mechanisms Of Cortical Plasticity And Facilitation Of Functional Recovery Following Stroke
Funder
National Health and Medical Research Council
Funding Amount
$427,500.00
Summary
Specific regions of the human brain have been shown to reorganise following damage to the brain or peripheral nerves. This reorganisation is seen in both young and older subjects and is thought to be useful in helping to restore function. For example, following a stroke a patient may, initially, be unable to move one arm. However, in the following weeks and months some function may return. A number of mechanisms may be responsible for this improvement. However, it is likely that at least some of ....Specific regions of the human brain have been shown to reorganise following damage to the brain or peripheral nerves. This reorganisation is seen in both young and older subjects and is thought to be useful in helping to restore function. For example, following a stroke a patient may, initially, be unable to move one arm. However, in the following weeks and months some function may return. A number of mechanisms may be responsible for this improvement. However, it is likely that at least some of the improvement is due to reorganisation within the sensorimotor cortex. Following the stroke the control of the arm may be taken over by adjacent undamaged regions of the brain. This reorganisation allows impressive functional recoveries to occur. We have preliminary evidence to support the idea that patterns of activity generated in peripheral nerves (afferent input) following stroke may be crucial for the development of the organisational changes seen within the brain. We have shown that by applying specific patterns of sensory input we are able to produce organisational changes within the motor cortex of control subjects. Also, we have been able to induce similar changes in stroke patients. These changes have been accompanied by improvements in motor control. These novel and exciting findings support our hypothesis that by applying certain patterns of afferent input to patients following stroke we will be able to facilitate functional recovery by maximising reoganisation within the cortex. In the present project we will establish the organisation patterns in the brain of stroke patients and contrast the findings with control subjects. Secondly we will investigate the potential for facilitating recovery of stroke patients by the application of specific patterns of afferent input. These novel experiments may lead to important therapeutic developments that will benefit the large population of patients suffering strokes.Read moreRead less
Vestibular Reflexes Evoked By Brief Lateral Head Acclerations: A New Measure Of Utricular Function
Funder
National Health and Medical Research Council
Funding Amount
$225,357.00
Summary
The vestibular (balance) organs are difficult to investigate as they lie deep within bone. Disease of these organs may cause severe vertigo, imbalance and difficulty with vision. This project attempts to build on earlier developments in my laboratory and thereby improve understanding and diagnosis of these disorders. This grant relates to a new form of stimulation which may allow simple assessment of an important part of the vestibular apapratus, the utricle.
Assessment Of Vestibular Function And Balance In Humans
Funder
National Health and Medical Research Council
Funding Amount
$205,500.00
Summary
This proposal focuses upon the function of the vestibular apparatus and the related problem of impaired balance. The vestibular apparatus contains receptors which help us to maintain balance. Their clinical assessment is difficult because they are small and lie deep within the skull. With previous NH and MRC support, I have been able to develop a series of new tests to assess the function of the vestibular apparatus and these are having significant clincal impact. Amongst the findings has been a ....This proposal focuses upon the function of the vestibular apparatus and the related problem of impaired balance. The vestibular apparatus contains receptors which help us to maintain balance. Their clinical assessment is difficult because they are small and lie deep within the skull. With previous NH and MRC support, I have been able to develop a series of new tests to assess the function of the vestibular apparatus and these are having significant clincal impact. Amongst the findings has been a clear demonstration that vestibular function declines with age, starting relatively early. This proposal builds upon the findings of the previous application. Two main types of investigations are planned. In one a new technique of activating the vestibular apparatus (localised skull vibration) will be used to study the brain areas that receive its signals (evoked potentials). This will be the first time that it has been possible to study the connections between the balance organs and the cortex of the brain in intact humans. I will apply the technique to patients with disturbed vestibular function to improve our knowledge of how the brain adapts to disease of these organs. In the second part of this study, a series of recordings will be done measuring sway under a variety of conditions both in normal volunteers and in patients with some common disease states affecting balance. This should reveal new information about both the factors that affect normal balance function and why balance is disturbed in these diseases.Read moreRead less
The Role Of Neuropeptides In The Acute And Long-term Effects Of MDMA, Methamphetamine And GHB
Funder
National Health and Medical Research Council
Funding Amount
$472,321.00
Summary
The widespread use of 'party drugs' (ecstasy, methamphetmaine and GHB) is a major health issue in Australia. We propose a novel hypothesis that key acute and long-term effects of these drugs may involve an action on the neuropeptide oxytocin. A number of experiments are planned to test this hypothesis. The findings from this project will be used to better understand and to explore novel treatments for people who suffer problems as a result of using these drugs.
Brain Angiotensin: Generation, Localisation And Physiological Function
Funder
National Health and Medical Research Council
Funding Amount
$209,250.00
Summary
The renin angiotensin system is one of the major homonal systems of the body that regulate the cardiovascular system and bodily salt and water balance. Drugs that inhibit the function of this system by reducing the blood level of the hormone angiotensin II or blocking the receptors at which it acts are in the forefront of treatment of high blood pressure and heart failure. It has been proposed that a separate brain renin angiotensin system exists that is not influenced by angiotensin II in the b ....The renin angiotensin system is one of the major homonal systems of the body that regulate the cardiovascular system and bodily salt and water balance. Drugs that inhibit the function of this system by reducing the blood level of the hormone angiotensin II or blocking the receptors at which it acts are in the forefront of treatment of high blood pressure and heart failure. It has been proposed that a separate brain renin angiotensin system exists that is not influenced by angiotensin II in the blood stream because of the blood-brain barrier. Strains of mice in which the genes that code for two components of this system - angiotensin converting enzyme (the enzyme responsible for generating angiotensin II) and angiotensinogen (the protein which gives rise to angiotensin II) provide excellent tools to elucidate this system in the brain. By studying these mice we will be able to determine whether angiotensin converting enzyme is necessary in the brain for foreming angiotensin II, and we will be able to determine the sites in the brain where authentic angiotensin peptides exist. We will also determine whether angiotensin II transmits information between neurons in the brain that play a role in control of the cardiovascular system and body fluid balance.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
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
Reinstating Emotion Perception After Brain Damage: An Experimental Approach
Funder
National Health and Medical Research Council
Funding Amount
$338,421.00
Summary
Many people with traumatic brain injury (TBI) cannot recognise emotions in others. This disrupts social behaviour leading to isolation and unemployment. In this project we determine whether: (1) selectively attending to a person's expression improves empathy and emotion recognition; (2) whether mimicking an expression improves recognition of the emotion and; (3) whether poor recognition of emotional tone of voice (prosody) and audiovisual displays is improved by focusing on voice or face alone.