Plasticity Of Sensorimotor Representations In Adult Primate Cortex
Funder
National Health and Medical Research Council
Funding Amount
$554,656.00
Summary
Cells in some regions of the brain, collectively known as the sensorimotor cortex, control our capacity to purposefully move the arms and hands. Damage to these regions in adults causes severe deficits. However, rehabilitative training can restore some control over the muscles. To understand how the brain circuits change to compensate for injury, and what effect rehabilitation may have on these changes, I will study cellular alterations in the movement control pathways in the cerebral cortex.
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
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.
Lesions of the primary visual area (V1) are sufficient to cause blindness, even though there are many other brain areas normally involved in vision. However, when V1 is lesioned very early in life people show some recovery, and may be able to see well enough to perform everyday activities. In order to understand what happens in the brain that allows this preservation of vision, we will study changes in the pathways linking the eyes to the brain, following lesions at different ages.
Over thirty different areas, comprising nearly half the primate cerebral cortex, are involved in processing visual information. From the anatomical viewpoint, each of these areas should be capable of receiving visual information independently, through parallel anatomical channels involving the brainstem. Yet, it has been observed that lesion of one particular area (the primary visual area, V1) results in loss of vision. This raises several questions. What type of visual information is carried by ....Over thirty different areas, comprising nearly half the primate cerebral cortex, are involved in processing visual information. From the anatomical viewpoint, each of these areas should be capable of receiving visual information independently, through parallel anatomical channels involving the brainstem. Yet, it has been observed that lesion of one particular area (the primary visual area, V1) results in loss of vision. This raises several questions. What type of visual information is carried by the parallel pathways to the other visual areas? Why aren t these other areas capable of sustaining vision without V1? Do V1 lesions trigger changes in the adult brain, which affect the other visual areas? As a step towards answering these questions, we will study the neural pathways that convey visual information directly to the middle temporal area (MT). MT is one of the best-characterised visual areas, and the anatomy of its neural inputs is well known, facilitating the interpretation of the results. We will investigate the type of visual information being sent to MT after lesions of V1, as well as the changes in the electrical responses of MT cells which result from this type of condition. This is a basic science study, the primary benefit of which will be advancement of knowledge on the mechanisms that underlie visual processing in normal and pathological situations. However, this type of work may also lay the groundwork for developments in areas of applied research. These may include medicine (e.g. the design of better rehabilitation strategies for people with brain damage), robotics- artificial intelligence (e.g. the development of more robust artificial systems capable of vision), and cognitive sciences (e.g. a better understanding of factors that limit human responses to visual stimuli).Read moreRead less
Developmental Plasticity In The Nonhuman Primate Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$464,417.00
Summary
A phenomenon that has puzzled many for a number of years is why damage to the visual brain during infancy has far less of an impact on visual capacity than the same lesion suffered later in life. This project hopes to uncover this mystery and see how brain 'wiring' is altered to compensate.
Much of the human brain is devoted to vision, which requires the integrated activity of many interconnected areas of the cerebral cortex. Damage to these areas is a relatively common complication of preterm delivery and- or perinatal conditions including trauma and infection. The severity of both the short- and long-term effects of these lesions appears to be related to the time of the damage. The aim of this project is to investigate the way in which the multiple visual areas of the brain devel ....Much of the human brain is devoted to vision, which requires the integrated activity of many interconnected areas of the cerebral cortex. Damage to these areas is a relatively common complication of preterm delivery and- or perinatal conditions including trauma and infection. The severity of both the short- and long-term effects of these lesions appears to be related to the time of the damage. The aim of this project is to investigate the way in which the multiple visual areas of the brain develop and become 'wired' together in the period following birth. We will also determine if there are mechanisms which allow alternate routes to be found for processing visual information while the brain is still establishing connections between its multiple areas. This will allow us to understand the anatomical and physiological bases of the deficits caused by early damage to the visual areas of the brain, and perhaps point to strategies that will lead to improved recovery of visual function.Read moreRead less
A Randomised Trial Of Constraint Induced Movement Therapy And Botulinum Toxin A In Children With Congenital Hemiplegia.
Funder
National Health and Medical Research Council
Funding Amount
$399,995.00
Summary
Congenital hemiplegia occurs in over 1 million children under 21 years of age in the industrialized world. It is the most common type of cerebral palsy, accounting for 36 percent of children diagnosed with this lifelong condition. We intend to determine if a promising new treatment approach is effective in providing a superior and lasting benefit, compared to conventional techniques. Children with hemiplegia usually have the intellectual capacity to attend normal school; however the impaired arm ....Congenital hemiplegia occurs in over 1 million children under 21 years of age in the industrialized world. It is the most common type of cerebral palsy, accounting for 36 percent of children diagnosed with this lifelong condition. We intend to determine if a promising new treatment approach is effective in providing a superior and lasting benefit, compared to conventional techniques. Children with hemiplegia usually have the intellectual capacity to attend normal school; however the impaired arm reduces independence in activities of daily living and can compromise their ability to participate in educational, leisure and vocational roles. Previously we have shown that a program of upper limb rehabilitation in children with spasticity was effective in improving participation and quality of life. We have also shown that rehabilitation combined with Botulinum toxin A (Botox) can further improve functional activity. We believe that a new method of therapy, that has been used effectively in Adults with stroke, called Constraint Induced Movement Therapy (CIMT) may also be beneficial in the treatment of children with congenital hemiplegia. In CIMT, the unimpaired arm is constrained in a glove to promote use of the impaired arm (hemiplegic arm). We predict that, combined with the Botox treatment, CIMT will provide a superior and longer lasting benefit compared to standard rehabilitation combined with Botox. The primary aim of our study is to test this hypothesis in a controlled trial. A secondary aim is to further our understanding of the central neurovascular mechanisms underlying changes in upper limb function. To achieve this, we will use Functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS) to measure central activation in the parts of the brain controlling movement. Improving our understanding of the mechanisms involved in this condition is an essential next step towards providing a more effective and long lasting treatment.Read moreRead less