THE NEUROBIOLOGICAL BASIS OF INDIVIDUAL DIFFERENCES IN SUSCEPTIBILITY TO THE CONSEQUENCES OF STRESS
Funder
National Health and Medical Research Council
Funding Amount
$583,875.00
Summary
Stress plays a major role in the development and progression of many different mental health disorders. However, as we all know, the effects of stress on one person can be very different from its effects upon another. This is at least partly explained by differences in individual coping styles. When faced with a stressful situation without a ready solution, people tend to divide into two broad camps: those with an innate tendency to adopt passive coping strategies, such as avoidance, and those t ....Stress plays a major role in the development and progression of many different mental health disorders. However, as we all know, the effects of stress on one person can be very different from its effects upon another. This is at least partly explained by differences in individual coping styles. When faced with a stressful situation without a ready solution, people tend to divide into two broad camps: those with an innate tendency to adopt passive coping strategies, such as avoidance, and those that tend towards active coping strategies, such as attempting to take control of the situation. Previous studies have provided findings that suggest that passive coping is more common amongst sufferers of depression, post-traumatic stress disorder, and chronic pain syndrome than is active coping. But is this cause, or effect? And what are the intervening brain mechanisms? We attempt to address such questions in the present project using an animal model in which social conflict has been shown to trigger depression-like symptoms. In particular we wish to: (i) determine whether the patterns of brain activity triggered by social conflict are different for active vs. passive copers; (ii) determine whether the depression-like consequences of social conflict are more severe in passive than in active copers; (iii) determine whether differences in coping style and vulnerability to social conflict stress are due to the actions of a particular neurotransmitter, dopamine, in the prefrontal cortex of the brain; (iv) determine whether the actions of antidepressants might be attributable changes in prefrontal cortex dopamine function which in turn promote active coping in preference to passive coping. These studies will provide exciting new information about the neurobiological basis of individual differences in vulnerability to the harmful effects of stress, and thus will offer the hope of developing new ways of preventing devastating illnesses such as depression.Read moreRead less
Fluid intake is essential for survival. Disorders of thirst whether they be excessive or inadequate have dire conseqences as evidenced in recent heat waves in Europe and Indiawhere thousands of lives were lost primarily in the elderly whose thirst mechanisms are often disrupted. The excessive fluid intake, seen in psychotic disorders such as schizophrenia, is equally damaging. Much of the research over the last 50 years has concentrated on the hypothalamic regulation of thirst. This project will ....Fluid intake is essential for survival. Disorders of thirst whether they be excessive or inadequate have dire conseqences as evidenced in recent heat waves in Europe and Indiawhere thousands of lives were lost primarily in the elderly whose thirst mechanisms are often disrupted. The excessive fluid intake, seen in psychotic disorders such as schizophrenia, is equally damaging. Much of the research over the last 50 years has concentrated on the hypothalamic regulation of thirst. This project will attempt, for the first time, to define the location in the cerebral cortex of the drive to ingest water (perception of thirst).Read moreRead less
The Role Of Afferent Input In The Development Of Focal Task Specific Dystonia
Funder
National Health and Medical Research Council
Funding Amount
$213,000.00
Summary
The term dystonia is used to describe a condition that is characterised by abnormal muscle activation patterns. This leads to impaired control of voluntary movements. Depending upon which part of the body is affected, dystonia may be classified as generalised (affecting two or more body segments), hemi (involving one side), segmental (involving adjacent body parts or a segment), or focal (affecting one part of the body). Many of the focal dystonias are also task specific and the aim of this prop ....The term dystonia is used to describe a condition that is characterised by abnormal muscle activation patterns. This leads to impaired control of voluntary movements. Depending upon which part of the body is affected, dystonia may be classified as generalised (affecting two or more body segments), hemi (involving one side), segmental (involving adjacent body parts or a segment), or focal (affecting one part of the body). Many of the focal dystonias are also task specific and the aim of this proposal is to investigate these task-specific focal dystonias. Task-specific focal dystonia is common in the community and causes considerable suffering and loss of productivity. For example, writer's cramp (a common form of task specific focal dystonia) is probably the commonest cause of writing difficulty in patients in whom this is the sole complaint. No treatment regimen has been shown to be effective in alleviating it's often debilitating symptoms. The aim of these studies is to further define the pathophysiological changes seen in task-specific dystonia and investigate the mechanisms responsible for their generation. Using the techniques of transcranial magnetic stimulation and peripheral nerve stimulation we will investigate the organisation of the motor cortex in this condition and examine the influence of afferent input on intrinsic cortical circuitry. We hypothesise that the motor regions of the brain are more sensitive to the particular repeated patterns of sensory information reaching the brain during repetitive movement and this results in abnormal alterations in organisation that may be responsible for the symptoms of dystonia. Additionally, we predict that it may be possible to reverse these organisational changes by applying novel patterns of nerve stimulationRead moreRead less
Thrombolysis is a method of dissolving the blood clot that is the cause of the majority of strokes in Australia. The first major trial to demonstrate benefit for this treatment was published some 11 years ago but treatment has not been widely implemented across Australia because of the difficulties in giving treatment within the very tight time window for which treatment is currently approved (patients must get to hospital, be scanned and start treatment within 3 hours of the onset of the stroke ....Thrombolysis is a method of dissolving the blood clot that is the cause of the majority of strokes in Australia. The first major trial to demonstrate benefit for this treatment was published some 11 years ago but treatment has not been widely implemented across Australia because of the difficulties in giving treatment within the very tight time window for which treatment is currently approved (patients must get to hospital, be scanned and start treatment within 3 hours of the onset of the stroke). Other factors which have limited implementation of treatment in Australia are continued debate over the trial data for this treatment as only one of the 5 major trials was positive. In addition, virtually no patients aged over 80 years old were included in the previous trials, and as this age group represents about a third of all stroke in Australia, new data in this age group is required. As a result of the difficulty in giving a treatment within such a tight time window and the ongoing debate about the trial data, few Australians are currently treated and thus the public health impact is negligible. In to change clinical practice, we need reliable data from a large convincing further trial of thrombolysis with the more realistic time window of 6 hours. The Third International Stroke Trial (IST-3) is a large international collaborative effort to determine whether thrombolysis treatment offered to a wider range of patients up to 6 hours from stroke onset results in an increase in long-term independent survival. Data from such a trial is most likely to change clinical practice and lead to an important public health benefit.Read moreRead less
The Influence Of Human Cortical Rhythms On The Induction Of Plasticity
Funder
National Health and Medical Research Council
Funding Amount
$298,898.00
Summary
The human brain has a great capacity to reorganise. This capacity is known as plasticity and is behind our ability to learn new skills. Plasticity is important for recovery from brain injury. The recently developed technique of transcranial magnetic stimulation can be used to manipulate plasticity in the human brain This approach offers new and exciting therapeutic opportunities. This project is aimed at optimising this technique.
Molecular And Cellular Changes Following A Cortical Injury: What Role Do They Play In Regeneration?
Funder
National Health and Medical Research Council
Funding Amount
$499,625.00
Summary
Damage to the visual areas of the brain is common after, for example stroke, neurotrauma or hypoxia. The injury often manifests in the form of a scar caused by a specific type of brain cell (astrocyte). This scar acts as a barrier to the cells which transmit information (neurones), preventing re-establishment of connectivity, thus functional recovery. We will see if we can reduce this scar and enhance re-connectivity after injury by blocking some of the molecules that brain cells express.
Alzheimer's Disease And Related Disorders: Mechanism Of Tau Pathology In Established And Novel Transgenic Animal Models
Funder
National Health and Medical Research Council
Funding Amount
$423,017.00
Summary
Alzheimer's disease (AD) is a devastating neurodegenerative disease for which no cure is available. It affects more than 15 million people worldwide. There are estimates that by 2040, approximately 500'000 Australians will suffer from AD, with associated health costs of about 3% of the GDP. AD is characterized by two major brain lesions, beta-amyloid plaques and neurofibrillary tangles (NFTs). The latter contain a protein called tau which is in a fibrillar and highly phosphorylated state. We wer ....Alzheimer's disease (AD) is a devastating neurodegenerative disease for which no cure is available. It affects more than 15 million people worldwide. There are estimates that by 2040, approximately 500'000 Australians will suffer from AD, with associated health costs of about 3% of the GDP. AD is characterized by two major brain lesions, beta-amyloid plaques and neurofibrillary tangles (NFTs). The latter contain a protein called tau which is in a fibrillar and highly phosphorylated state. We were the first to establish a transgenic animal model of pre-tangles and, together with Dr. Hutton's laboratory, of NFT formation. We could further show that injections of beta-amyloid into brains of our tau mutant mice enhanced the NFT pathology in these mice. By Functional Genomics we identied genes and proteins, which are induced by tau expression. The specific aim of this proposal is to determine whether oxidative stress enhances the tau pathology in our tau mutant mice and whether distinct brain areas are particularly susceptible to this kind of stress. The reason for addressing this question is twofold: On the one hand, we have found in our mice that reactive oxygen species are increased, secondly it is known that some brain areas in the AD brain are degenerating, whereas others are not. A second aim is to develop novel tau transgenic models where individual interactions of tau with cellular proteins are disturbed. Finally, we want to determine whether the two kinases BMX and FAK and the phosphatase PPV regulate tau phosphorylation in vivo. Together, we hope that our efforts lead to a better understanding of the pathogenic mechanisms in AD and related disorders. As pathocascades are likely to be shared between a range of diseases, these findings may also contribute to other fields of research, such as Parkinson's disease. Ultimately, these efforts will assist in the development of a safe treatment of AD.Read moreRead less
Improving Oral health is a priority of the NHMRC Strategic Plan 2003-06. The proposed research is consistent with this priority as we will achieve a better understanding of the cortical control of human jaw muscles, which serves as the foundation for understanding conditions in which their function is impaired, and the development of rational therapies for these conditions. Transcranial magnetic stimulation will be used to activate the motor cortex and corticobulbar descending pathway to the jaw ....Improving Oral health is a priority of the NHMRC Strategic Plan 2003-06. The proposed research is consistent with this priority as we will achieve a better understanding of the cortical control of human jaw muscles, which serves as the foundation for understanding conditions in which their function is impaired, and the development of rational therapies for these conditions. Transcranial magnetic stimulation will be used to activate the motor cortex and corticobulbar descending pathway to the jaw muscles. The AIM 1 study will provide important new information about the functional organisation of the motor cortex in the control of jaw muscles during speech. This information is needed to improve understanding of dysarthria, a common disturbance of speech due to impaired muscular control following unilateral cortical stroke, and less common conditions involving speech motor control such as spasmodic dysphonia (a cranial dystonia) and dysprosody (disturbance of speech articulation and rhythm found in Parkinson s disease). The AIM 2 and 3 studies will provide a comprehensive characterization of cortical inhibitory mechanisms that are an important but poorly understood component of the cortical control of jaw muscles. This information is necessary to understand normal function, and the mechanisms of disturbances to jaw muscle function with neurological disease or injury. The AIM 4 studies will show whether impaired cortical inhibition contributes to the pathophysiology of two poorly understood disorders affecting jaw muscles (bruxism and oromandibular dystonia). Current therapies for these conditions are unsatisfactory, due to a limited understanding of the mechanisms involved. If cortical inhibition is abnormal in these conditions this will lead to novel treatment therapies (e.g., drugs to correct the imbalance, or strategies to induce plastic change in the cortex).Read moreRead less
The corticospinal pathway is the major route from the brain to the spinal cord for the control of voluntary movement in people. Little is known about how transmission through this pathway might alter with activity. It is known that, elsewhere in the brain, connections between nerve cells can be made stronger or weaker by specific patterns of activity and it is thought that such changes underlie learning and memory. We propose that similar changes might happen in the spinal cord at the connection ....The corticospinal pathway is the major route from the brain to the spinal cord for the control of voluntary movement in people. Little is known about how transmission through this pathway might alter with activity. It is known that, elsewhere in the brain, connections between nerve cells can be made stronger or weaker by specific patterns of activity and it is thought that such changes underlie learning and memory. We propose that similar changes might happen in the spinal cord at the connection between the nerve cells which carry signals from the brain and the nerve cells which carry the signals out to the muscle. This project will demonstrate that the connections in the pathway from the brain to the muscle can be strengthened or weakened in a controlled way by imposed patterns of activity. In addition, we know that after voluntary contractions, there are dramatic changes in the way signals in this pathway are transmitted to muscles. After brief strong voluntary contractions, muscle responses are immediately reduced. After longer contractions in which the muscles become fatigued, the reduction is followed by an increase in responses which can last many minutes. Thus, this project will also study changes in the pathway from the brain to the muscle after natural activity. The effects of changes induced by artificial or natural activity on the control of voluntary movement will also be investigated. Understanding how activity drives changes in the pathway that controls voluntary movement is important for all situations that involve learning motor tasks. These include normal development and learning of motor skills, as well as rehabilitation after all kinds of nerve or muscle injury. It is also important in understanding motor changes that occur when activity is altered by disorders like spinal cord injury or stroke. Improved understanding of the processes occuring should allow improvement in rehabilitation therapies.Read moreRead less
Signalling Mechanisms Regulating Neurogenesis And Neurite Outgrowth
Funder
National Health and Medical Research Council
Funding Amount
$486,000.00
Summary
Injury and diseases of the central nervous system (CNS), such as traumatic injury, stroke, Parkinson's, Huntington's and Alzheimer's disease, affect a substantial number of Australians each year and often have long-term consequences for sufferers and their families. This is primarily due to a lack of robust repair of the damage and a paucity of therapeutic strategies available for treatment. However, although many hurdles are yet to be faced, there is a substantial body of evidence that has emer ....Injury and diseases of the central nervous system (CNS), such as traumatic injury, stroke, Parkinson's, Huntington's and Alzheimer's disease, affect a substantial number of Australians each year and often have long-term consequences for sufferers and their families. This is primarily due to a lack of robust repair of the damage and a paucity of therapeutic strategies available for treatment. However, although many hurdles are yet to be faced, there is a substantial body of evidence that has emerged in recent years, that has led to the view that repair of the central nervous system following injury of disease may indeed be a possibility. Effective neural repair is likely to require a multi-factorial approach, including blockage of neuronal death, replacement of lost neurons by neural stem cells, and regulation of appropriate subsequent neurite outgrowth and formation of correct connections. We have shown that a regulator of cytokine signaling, SOCS2, promotes neuronal differentiation and neurite outgrowth. This project aims to continue our investigations of the role of SOCS2 and interacting factors in regulating neuronal differentiation as well as substantially expanding our investigations into the role of SOCS2 in regulating neurite outgrowth, using both in vitro and in vivo models. An understanding of the mechanisms involved in these processes may allow us to derive therapies for the repair of the nervous system after injury or disease.Read moreRead less