Proprioception is how we sense the position of our joints, the movements of our joints, and the forces generated by our muscles. Disturbances of proprioception can cause major disruption of all movements and postures. We will undertake novel studies of how signals generated in the brain which command our movements contribute to all key aspects of proprioception. Finally we will unravel how the brain builds up the overall 'scheme' of our body which we need to make any accurate movement.
This is a study of the senses which arise from our muscles and which tell us where our different body parts are, at any point in time. These senses, collectively called proprioception, are also involved in the automatic, unconscious control of our muscles. So, ultimately, they allow us to stand and to move freely with precision and confidence, even in the dark. One of these senses, the sense of effort or of heaviness, is believed to be generated within the brain. It intensifies when we become fa ....This is a study of the senses which arise from our muscles and which tell us where our different body parts are, at any point in time. These senses, collectively called proprioception, are also involved in the automatic, unconscious control of our muscles. So, ultimately, they allow us to stand and to move freely with precision and confidence, even in the dark. One of these senses, the sense of effort or of heaviness, is believed to be generated within the brain. It intensifies when we become fatigued. These experiments will be concerned with finding out more about how this works. We have a method that uses magnetic stimulation of the brain to change its control of our muscles. Using it we will learn how this sense is generated. When we close our eyes and move our limbs we realise that we know exactly where they are at any point in time. It remains uncertain exactly how this information is generated within the nervous system. One idea, arising from some recent experiments which we want to test, is that as we move the limb, the skin over the moving parts is stretched and stretch-sensitive nerve endings in the skin provide us with information about the movement. Alternatively, perhaps it is the effort we exert to maintain limb position against the force of gravity which tells us where the limb is. In another recent study we have found that when a muscle has become painful from excessive exercise or from some local strain injury, our ability to control the muscle and so move the limb is no longer as effective. We want to study the underlying nervous mechanisms responsible for the changes in movement control. Are they designed to spare the muscle while it recovers from injury? How are they brought about? All of this work is important for a better understanding of ourselves, for a better clinical diagnosis when something goes wrong and for improved treatment of diseased or injured muscles.Read moreRead less
Human Movement Control: Basic And Applied Neurophysiology
Funder
National Health and Medical Research Council
Funding Amount
$948,684.00
Summary
My research targets mechanisms underlying human movement, ways in which they can be deranged, and ways in which interventions can diminish impairments. It focuses on gaps in understanding and in clinical practice. Work in our broad ‘Motor Impairment’ NHMRC Program underpin my research. It is supplemented by new work on respiratory neurophysiology which has already delivered basic and clinical insight into neural control of the main breathing muscles and more recently upper airway muscles.
INVESTIGATING PROPRIOCEPTION AND SENSORIMOTOR CONTROL IN HUMANS DEVOID OF FUNCTIONAL MUSCLE SPINDLES
Funder
National Health and Medical Research Council
Funding Amount
$335,983.00
Summary
Specific genetic mutations can lead to widespread changes in the body. Here we are looking at congenital Hereditary and Sensory Autonomic Neuropathy type III (HSAN III). Affected individuals have difficulty walking, which progressively worsens over time. This series of experiments aims to increase our understanding of the underlying neurophysiological disturbances in HSAN III.
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