I am a neurophysiologist who examines the neural control of movement and the interaction of sensation and movement in human subjects. I study cortical and motoneuronal events during exercise and muscle fatigue. I also study proprioception i.e. the sensati
Signalling Of Muscle Force By Golgi Tendon Organs During Exercise And Fatigue
Funder
National Health and Medical Research Council
Funding Amount
$181,320.00
Summary
It is a common experience for objects being carried to feel heavier and tasks needing muscular effort to become more difficult as one becomes tired and the muscles fatigue during exertion. The sensation of muscle force depends on two factors. One, a sense of the effort required to perform a task, is generated in the central nervous system and. The other, a sense of the force actually developed by the muscles, is generated in the muscles themselves by signals from sensory receptors called Golgi t ....It is a common experience for objects being carried to feel heavier and tasks needing muscular effort to become more difficult as one becomes tired and the muscles fatigue during exertion. The sensation of muscle force depends on two factors. One, a sense of the effort required to perform a task, is generated in the central nervous system and. The other, a sense of the force actually developed by the muscles, is generated in the muscles themselves by signals from sensory receptors called Golgi tendon organs. The sensation of muscle force and the heaviness of objects results from a combination of both senses, but the contribution of each is unknown. The aim of the project is to determine whether the disturbance of force sense in fatigued muscles results from changes in the way tendon organs signal the actual force developed by the muscles. This will be important for understanding how force sense is disturbed following exercise and in disease states, and for understanding the normal way muscle force is sensed in everyday situations. Disturbances of force sense after exercise will be documented in human subjects by asking them to generate what they perceive to be equal forces in both arms or legs, before and after one limb only is exercised. Errors in force estimation will show up as mismatches between the two limbs. The difficulty with human experiments is that the signals generated by tendon organs cannot be measured directly, but only inferred, perhaps wrongly. This difficulty will be overcome by measuring tendon organ activity directly in anaesthetised animals, where the muscles will be electrically stimulated to perform exercise similar to that in the human experiments. A change in tendon organ signalling will be taken to mean that similar changes in humans could be responsible for disturbances of force sense. In further experiments, the mechanism of the changes will be explored.Read moreRead less
Bilateral Movement Therapy In Post-stroke Hemiparesis
Funder
National Health and Medical Research Council
Funding Amount
$265,993.00
Summary
Stroke is the leading cause of long-term disability in adults in Australia, accounting for approximately 25% of all disability. A common motor disability resulting from stroke is hemiparesis, weakness or paralysis on one side of the body. This disability severely impairs an individual's capacity to perform activities of daily living, making them dependent on relatives and health professionals for daily care. By developing effective interventions to treat stroke-induced hemiparesis both the disab ....Stroke is the leading cause of long-term disability in adults in Australia, accounting for approximately 25% of all disability. A common motor disability resulting from stroke is hemiparesis, weakness or paralysis on one side of the body. This disability severely impairs an individual's capacity to perform activities of daily living, making them dependent on relatives and health professionals for daily care. By developing effective interventions to treat stroke-induced hemiparesis both the disability caused by stroke and the associated personal and financial costs will be lessened. A number of interventions focusing on the affected side (unilateral), including active movements and muscle stimulation are being investigated as possible treatments for stroke-induced hemiparesis. Recent evidence suggests that involving the unaffected side simultaneously (bilateral therapies) could be effective, and may provide addtional benefits over unilateral therapies. The aim of this research is to thoroughly examine the effectiveness of bilateral therapies by incorporating them into established interventions. The findings from these studies will aid in the development and refinement of movement therapies aimed at promoting recovery from stroke-induced hemiparesis.Read moreRead less
Humans, like all animals, receive similar, although not identical, visual input via the eyes. This information is combined in the brain to form a single view of the outside world. In this proposal we aim to understand how single neurons in the brain process the combined information received from both eyes. This work will increase our understanding of the underlying cellular mechanisms responsible for sight, and determine what changes occur when visual input is impaired through blindness.
The Plastic Effects Of Long-term Partial Deafness And Chronic Cochlear Implant Use On The Response Of Primary Auditory Cortex To Combined Electro-acoustic Stimulation
Funder
National Health and Medical Research Council
Funding Amount
$560,267.00
Summary
Cochlear implants were originally used only in cases of profound deafness, but are now being used in patients who have some residual hearing at low frequencies. Our goal is to better understand how the electrical information from the cochlear implant and the acoustic information provided by the residual hearing are combined in the brain to produce unified perception of the auditory environment.
Synaptic Integration And Plasticity In The Rat Piriform Cortex
Funder
National Health and Medical Research Council
Funding Amount
$250,500.00
Summary
The human cerebral cortex is the pinnacle of evolution. It is the most complex structure known, responsible for all of those skills - like language and reasoning - that make our species so remarkable. It is also a major site of many brain diseases, like schizophrenia and epilepsy. An understanding of how the cerebral cortex works would be a remarkable achievement, of immeasurable benefit to human health. How can one go about studying such a complex structure? The strategy taken in this project i ....The human cerebral cortex is the pinnacle of evolution. It is the most complex structure known, responsible for all of those skills - like language and reasoning - that make our species so remarkable. It is also a major site of many brain diseases, like schizophrenia and epilepsy. An understanding of how the cerebral cortex works would be a remarkable achievement, of immeasurable benefit to human health. How can one go about studying such a complex structure? The strategy taken in this project is to begin by studying one of the simplest regions of the cerebral cortex, the olfactory (or piriform) cortex. The olfactory cortex is an evolutionarily ancient region of cortex, with a simpler architecture than other cortical regions. Its task is to process the sense of smell, a primitive sense that is more elaborated in lower animals than in humans. The broad goal of our research is to understand, by studying the olfactory cortex of rats, how olfactory processing occurs at the level of nerve cells (neurons). We will use a number of powerful techniques - including microelectrode recording and laser microscopy - to measure the electrical properties of individual neurons. We will also study the synaptic connections between neurons, and how these connections change following memory-inducing stimuli. It is hoped that this work will shed light on how the healthy cortex is able to process and store information, and how brain diseases cause these functions to deteriorate.Read moreRead less
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.
A TMS Study Of Cortical Plasticity In Schizophrenia
Funder
National Health and Medical Research Council
Funding Amount
$195,500.00
Summary
The cause of schizophrenia is uncertain. Several lines of evidence implicate abnormalities of functioning in circuits of nerve cells in the outer brain regions. Chemicals involved in these circuits are important for the capacity to learn and process new information and repeated exposure to stimuli. To date, it has been difficult to directly test the function of these circuits in patients with schizophrenia. Transcranial Magnetic Stimulation (TMS) is a non-invasive means of stimulating nerve cell ....The cause of schizophrenia is uncertain. Several lines of evidence implicate abnormalities of functioning in circuits of nerve cells in the outer brain regions. Chemicals involved in these circuits are important for the capacity to learn and process new information and repeated exposure to stimuli. To date, it has been difficult to directly test the function of these circuits in patients with schizophrenia. Transcranial Magnetic Stimulation (TMS) is a non-invasive means of stimulating nerve cells in superficial areas of the brain. During a TMS procedure, an electrical current passes through a coil placed close to the scalp. This current induces a magnetic field that stimulates electrical activity in nerves below the coil. TMS methods can be used to study the functioning of nerve cells in the brain and the way in which they respond to repeated stimuli. These methods will be used in this way to study the functioning of these circuits in patients with schizophrenia. This is likely to provide important information as to the function of these brain areas and may provide information that will guide the development of therapeutic interventions.Read moreRead less