Brain Plasticity Following Changes In Sensory Input
Funder
National Health and Medical Research Council
Funding Amount
$312,576.00
Summary
The research proposed here will investigate the mechanisms our brains use to adapt to changes in sensory input, as occurs following blindness, deafness, nerve damage or loss of a limb. The information gathered will help develop treatments for diseases associated with sensory loss, as well as those associated with deficits in our ability to learn and remember, such as Alzheimer's disease.
Mechanisms Of Glutamate Receptor Maturation In Chicken Brain
Funder
National Health and Medical Research Council
Funding Amount
$418,980.00
Summary
In the brain, many key proteins involved in signalling change during development as part of the fine tuning of the network of connections between nerve cells. Disorders of this fine tuning are thought to result in a number of neurological or psychiatric conditions such as epilepsy and schizophrenia. This project will investigate the maturation of signalling molecules in the brain (receptors for the neurotransmitter glutamate, key enzymes called protein kinases and protein phosphatases that contr ....In the brain, many key proteins involved in signalling change during development as part of the fine tuning of the network of connections between nerve cells. Disorders of this fine tuning are thought to result in a number of neurological or psychiatric conditions such as epilepsy and schizophrenia. This project will investigate the maturation of signalling molecules in the brain (receptors for the neurotransmitter glutamate, key enzymes called protein kinases and protein phosphatases that control the activity of receptors and scaffolding proteins that bind the whole lot into a signalling complex). The project uses chickens as a novel animal model because chicken brain has a slow maturation that occurs well after the initial wiring of the brain is complete. This enables the maturation changes to be clearly identified and experimentally modified. The project combines investigations at the molecular, physiological and behavioural levels. The effects of hormones and drugs on maturation will be investigated. Because brain maturation in humans is also slow an understanding of the way in which this maturation is controlled may provide insights into what causes some neurological-psychiatric disorders in children and adolescents and how to treat or prevent them.Read moreRead less
STK9, A Second Rett Syndrome Gene: Genetic And Functional Studies
Funder
National Health and Medical Research Council
Funding Amount
$468,750.00
Summary
Rett syndrome (RTT) is a devastating progressive disorder affecting motor and intellectual development. It is characterised by normal development for the first 6-12 months of life, followed by developmental regression with the loss of learned purposeful hand function, loss of acquired speech and communicative abilities, sometimes leading to the incorrect diagnosis of autism. It may be the most common cause of progressive mental retardation in girls, with an estimated prevalence in Australia of 1 ....Rett syndrome (RTT) is a devastating progressive disorder affecting motor and intellectual development. It is characterised by normal development for the first 6-12 months of life, followed by developmental regression with the loss of learned purposeful hand function, loss of acquired speech and communicative abilities, sometimes leading to the incorrect diagnosis of autism. It may be the most common cause of progressive mental retardation in girls, with an estimated prevalence in Australia of 1 per 10,000 females under the age of twelve years. It is a genetic disorder and occurs almost exclusively in females. In 1999, a gene (called MECP2) was identified which appears to be the cause of RTT in most girls and women with RTT. However, for 5 - 10% of RTT subjects, no gene change is found in the MECP2 gene, raising the possibility that other genes may also be responsible for RTT. Our research group has identified one of these genes. Known as STK9, little is known about this gene's function. Of great interest is the fact that our studies suggest that STK9 could also be a caus of intellectual disability in other patients, and with autism. The focus of this research project is to explore how common gene changes in STK9 are in a large number of children with RTT, intellectual disability and seizures, and autism with intellectual disability and seizures. Using cutting edge research technology, we will go on to study how STK9 interacts with MECP2 and other genes, in order to better understand how these genes may be detrimentally affecting brain function in girls and women with Rett syndrome and other neurological disorders. These studies will give us a greater understanding of normal brain development and function.Read moreRead less
Functional Characterisation Of A New Regulatory Mechanism For CaMKII At Synapses In Vivo
Funder
National Health and Medical Research Council
Funding Amount
$547,315.00
Summary
CaMKII is an important regulatory molecule in the brain where it plays an essential role in certain forms of learning and memory and in the appropriate development and maturation of neural pathways and undergoes specific changes in animal models of brain ischaemia and epilepsy. Recent evidence has shown that, in nerve cells, the regulation and role of CaMKII is more complicated than previously thought. This project will investigate the roles of a new control mechanism in regulating the function ....CaMKII is an important regulatory molecule in the brain where it plays an essential role in certain forms of learning and memory and in the appropriate development and maturation of neural pathways and undergoes specific changes in animal models of brain ischaemia and epilepsy. Recent evidence has shown that, in nerve cells, the regulation and role of CaMKII is more complicated than previously thought. This project will investigate the roles of a new control mechanism in regulating the function of CaMKII in nerve cells. The experiments will involve an international team of collaborators using cutting edge techniques at the molecular, cellular and whole animal level. This will provide a more complete understanding of how CaMKII influences brain function and allow an assessment of whether CaMKII regulation might be a suitable target for drugs aimed at protecting against the damaging effects of brain injury following stroke or heart attack.Read moreRead less
Mechanisms Of Testosterone Action On The Male Pelvic Autonomic Nervous System: The Role Of Estrogens
Funder
National Health and Medical Research Council
Funding Amount
$417,750.00
Summary
The aim of this project is to understand how the circulating hormone, testosterone, affects the autonomic nervous system in adult males. We are particularly interested in the effects this hormone has on the nerve supply of the urogenital organs, ie. the lower urinary tract and reproductive organs. We have already found that many different parts of this pelvic autonomic nervous system are androgen-sensitive, and if the levels of hormones drop significantly, then many properties of the neurons cha ....The aim of this project is to understand how the circulating hormone, testosterone, affects the autonomic nervous system in adult males. We are particularly interested in the effects this hormone has on the nerve supply of the urogenital organs, ie. the lower urinary tract and reproductive organs. We have already found that many different parts of this pelvic autonomic nervous system are androgen-sensitive, and if the levels of hormones drop significantly, then many properties of the neurons change. This is likely to impact negatively on reflexes like penile erection, prostate secretion and propulsion of seminal fluid. Our recent experiments suggest that many of these actions may be caused by testosterone acting in a way that does not involve the typical activation of its receptor molecule (the androgen receptor) and we think it is very likely that it is first converted by some pelvic autonomic neurons into estradiol. We have recently shown that estradiol has potent actions on signalling cascades in these neurons, and that many of the neurons make estrogen receptors. It is also possible that testosterone causes the release of growth factors from the organs, and these growth factors cause changes in their nerve supply. We will investigate both of these possibilities. The outcomes of this study will be relevant for understanding how pelvic autonomic reflexes are affected by endocrine disorders, ageing and various drugs that act on the endocrine system. Our results may also be useful for designing drugs that act on the endocrine system but with less side-effects on the nervous system.Read moreRead less
Thalamic And Basal Forebrain Contributions To Auditory Cortical Reorganization Produced By Partial Hearing Loss
Funder
National Health and Medical Research Council
Funding Amount
$364,768.00
Summary
When part of the cochlea is damaged in adult animals, leading to a partial hearing loss, the auditory area of the cerebral cortex reorganizes itself, so that the area deprived of input by the peripheral lesion is not silent, but is occupied by expanded representations of adjacent frequencies. This reorganization has been observed in a number of species, including non-human primates, and it seems likely that it also occurs in humans with cochlear damage and hearing loss of this sort. If it does, ....When part of the cochlea is damaged in adult animals, leading to a partial hearing loss, the auditory area of the cerebral cortex reorganizes itself, so that the area deprived of input by the peripheral lesion is not silent, but is occupied by expanded representations of adjacent frequencies. This reorganization has been observed in a number of species, including non-human primates, and it seems likely that it also occurs in humans with cochlear damage and hearing loss of this sort. If it does, it would have important consequences for the way in which input from a hearing aid or cochlear prosthesis (bionic ear) is processed in the brain. This Project is designed to clarify the nature of the systems in the brain that contribute to this form of cortical plasticity, using an animal model. One aim is to determine whether the plasticity is intrinsic to the cortex or occurs in the pathways over which information is conveyed to the cortex. This will be assessed by determining whether such plasticity is also found in the auditory thalamus, the final subcortical auditory nucleus from which information is sent to the cortex. The second aim is to determine whether the occurrence of plasticity is controlled by modulatory influences from the basal part of the forebrain. Neurons in this area project to many parts of the cortex, and evidence from other sensory systems suggests that these projections exert a permissive function, allowing the cortex to reorganize when input is altered. This aim will be pursued by determining whether cortical reorganization occurs after hearing loss when this basal forebrain system is inactivated. The significance of these studies is that they will elucidate the way in which the brain reorganizes itself when it is confronted with altered input. This information is important for our understanding of normal auditory information processing mechanisms and of the way in which input from prosthetic devices is processed in the hearing-impaired.Read moreRead less
Changes In Pelvic Autonomic Neurons After Spinal Nerve Injury
Funder
National Health and Medical Research Council
Funding Amount
$176,734.00
Summary
This project is about the effects of spinal injury on autonomic neurons that control the bladder, lower bowel and reproductive organs. One of the consequences of some types of spinal injury is that there are no signals being sent from the spinal cord to the nerve cells outside the cord, and this leads to poor bladder control, impotence, etc. We are mimicking this problem experimentally by damaging the spinal nerves that carry these signals. We have found that after this type of damage the pelvic ....This project is about the effects of spinal injury on autonomic neurons that control the bladder, lower bowel and reproductive organs. One of the consequences of some types of spinal injury is that there are no signals being sent from the spinal cord to the nerve cells outside the cord, and this leads to poor bladder control, impotence, etc. We are mimicking this problem experimentally by damaging the spinal nerves that carry these signals. We have found that after this type of damage the pelvic autonomic neurons make many new connections between each other, and the types of new connections depend on which spinal nerves have been injured. This leads to the question: are these new connections good or bad? ie are they helpful in trying to get organ control back to normal or will they stop the correct connections from the spinal cord from being made in the future? This project addresses these questions by using sophisticated techniques for staining and visualising individual nerve fibres growing out from the spinal cord. We will track how well these fibres grow back and connect with the pelvic autonomic neurons. In particular, we will see whether they make correct connections, and if these connections are influenced by the new fibres that have grown between the autonomic neurons in the interim period. We will also do physiological tests to see if the new connections have the correct function. The ultimate aim of these studies is not only to understand more about regeneration, but to see what determines whether the correct connections have been made - and ideally, to give us insight into how we can make regeneration work more quickly and accurately. We believe that this work is an important adjunct to other studies on spinal injury, which mostly focuses on regaining voluntary motor control (e.g. walking); however loss of bladder, bowel and reproductive function is another important quality of life issue for spinal injury patients.Read moreRead less
Sez-6 Signalling Mechanisms And Function In The Developing Neocortex
Funder
National Health and Medical Research Council
Funding Amount
$501,815.00
Summary
Over the course of evolution, the mammalian brain cortex has become disproportionately large with respect to other brain regions. The dramatic increase in processing power resulting from the increased neuronal number and connectivity in the cortex has enabled us to acquire functions that make us human, such as the use of language. In spite of the enormous difference in size between the brains of humans and those of mice, studies on cortical development in mice are relevant to humans since the or ....Over the course of evolution, the mammalian brain cortex has become disproportionately large with respect to other brain regions. The dramatic increase in processing power resulting from the increased neuronal number and connectivity in the cortex has enabled us to acquire functions that make us human, such as the use of language. In spite of the enormous difference in size between the brains of humans and those of mice, studies on cortical development in mice are relevant to humans since the organization of the cortex (thickness, layer patterning and regional specialization) is very similar in these two organisms, and indeed, in all mammals. A complex series of developmental events is required to produce a normal brain cortex. Malformations in the cortex occurring in human neurological disorders, including epilepsy and mental retardation, result from mutations in genes regulating crucial developmental processes. Failure of developing nerve cells to make the correct connections can result in these, or other, debilitating neurological conditions. We have evidence that a brain protein called Seizure-related gene 6 (Sez-6) regulates normal connectivity and function of neurons in the mature cortex. We will determine the molecular pathways used for signalling of Sez-6 and also investigate in detail the formation of connections between cortical neurons early in development and how these connections become aberrant in the absence of Sez-6 function.Read moreRead less
Regulation Of Regeneration Of Dopaminergic Neurones In The Substantia Nigra
Funder
National Health and Medical Research Council
Funding Amount
$115,880.00
Summary
Parkinson's Disease (PD) results from the progressive loss of brain cells in the part of the brain called substantia nigra. These brain cells contain a chemical called Dopamine (DA). The symptoms of Parkinson's disease arise when about 80% these DA neurones are lost suggesting that some form of compensation must occur up to this point. In previous studies we have demonstrated that one mechanism for this compensation is through sprouting or branching of the remaining neurones. We have preliminary ....Parkinson's Disease (PD) results from the progressive loss of brain cells in the part of the brain called substantia nigra. These brain cells contain a chemical called Dopamine (DA). The symptoms of Parkinson's disease arise when about 80% these DA neurones are lost suggesting that some form of compensation must occur up to this point. In previous studies we have demonstrated that one mechanism for this compensation is through sprouting or branching of the remaining neurones. We have preliminary evidence about the way this is sprouting and regeneration is controlled. The aim of this grant is to explore in detail the mechanisms whereby sprouting is induced and regulated. The significance of this study is that it may provide insights into the way in which regulation of regeneration of the nervous system is controlled. It has specific applications to therapies for Parkinson's disease.Read moreRead less