We stand without falling by using silent senses from muscles and the balance organs of the inner ear to unconsciously detect and control our movements. Since the leg muscles provide both the force and the sense, and critically rely on good circulation, they are vitally important. I propose to study how these sensory and muscle functions are used to control balance, posture and stepping reflexes, making it easier to identify older people who will fall and design new preventative strategies.
The Neurophysiology Of Abnormal Motor Development In Preterm Children
Funder
National Health and Medical Research Council
Funding Amount
$479,967.00
Summary
Better neonatal care has improved survival of prematurely born children. While most of these children will have no obvious brain lesion and attend mainstream schools, many will experience motor and cognitive difficulties and problems with social adjustment. However, the physiological mechanisms underlying this dysfunction are unknown. We will study preterm and term born children to elucidate the physiological mechanisms underlying motor and cognitive dysfunction associated with prematurity.
Muscle fatigue is common after exercise in healthy people. In many tasks, some muscles become more fatigued than others. Thus, the nervous system must often coordinate fatigued muscles (which produce less force) with unfatigued muscles. We will investigate how fatigue of one muscle alters the way the brain controls other muscles that are engaged in the same task or in unrelated tasks. This will aid understanding of the failures of coordination that lead to poor performance and injury.
Motor Unit Synchronisation And Neuromuscular Performance
Funder
National Health and Medical Research Council
Funding Amount
$198,500.00
Summary
The fine control of force is important for many everyday tasks such as writing, grasping objects between index finger and thumb, and fastening buttons. Factors that influence the ability to control force include the coordinated activation of groups of muscle fibres called single motor units. This proposal focuses on the concept that the coordinated activation of motor units is influenced by muscle activity and can impair the ability to produce finely controlled muscle contractions. The goal of t ....The fine control of force is important for many everyday tasks such as writing, grasping objects between index finger and thumb, and fastening buttons. Factors that influence the ability to control force include the coordinated activation of groups of muscle fibres called single motor units. This proposal focuses on the concept that the coordinated activation of motor units is influenced by muscle activity and can impair the ability to produce finely controlled muscle contractions. The goal of these studies is to explore the boudary conditions of the adaptive nature of the nervous system to examine how coordinated motor unit activity influences these aspects of neuromuscular performance. The outcomes of these experiments will identify if altering muscle activity influences the control of movement by altering single motor unit activity. These results will have direct application to the interpretation of abnormal movement control and tremor that is observed in certain neurological diseases such as Parkinson's disease. Furthermore, new information will be gained on the adaptability of the motor system and its role in the execution of fine motor tasks that may aid in the development of rehabilitation strategies following stroke or spinal cord injury.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.
Whether holding the arm still or standing, the brain uses a silent proprioceptive sense that unconsciously detects and controls our movements. Key sensory receptors for this sense are located within the muscles that are also contracting. This is a project to discover how proprioception is affected by muscle contraction and how this affects postural control. This will improve the management of many common disorders that affect movement and balance.
Physiology And Pathophysiology Of Trunk Control Mechanisms
Funder
National Health and Medical Research Council
Funding Amount
$168,958.00
Summary
The overall aim of this series of experiments is to understand how the spine is controlled and how this changes in disease. Altered control has been identified in people with low back pain, yet we still know very little about the normal mechanisms for protection and support of the spine. Back pain is a common affliction that affects about 5% of Australians each year and is the most common and expensive work-related injury in western society. An understanding of normal control and the mechanism o ....The overall aim of this series of experiments is to understand how the spine is controlled and how this changes in disease. Altered control has been identified in people with low back pain, yet we still know very little about the normal mechanisms for protection and support of the spine. Back pain is a common affliction that affects about 5% of Australians each year and is the most common and expensive work-related injury in western society. An understanding of normal control and the mechanism of dysfunction is critical for identification of risk factors and development of strategies for rehabilitation and prevention. The experiments are divided into two series. The first series addresses normal spinal control. The questions to be asked deal with how the brain copes with the challenge of using trunk muscles for breathing and spinal control at the same time, how the activity of the trunk muscles is affected by input from sensory receptors in the joints, ligaments and muscles of the spine, and whether intra-abdominal pressure can support the trunk. The second series deals with clinical populations. The first aim is to identify whether people with respiratory diseases use trunk muscles for spinal control and breathing at the same time. If they cannot, we predict that they will be more prone to low back pain. We will test this in a large study of incidence of low back pain in people with and without respiratory disease. The second study will investigate the pelvic floor muscles which are important for continence and assist with spinal control. We will investigate whether people with incontinence have poor spinal control and whether this leads to back pain. The final experiment will identify whether people with low back pain interpret sensory information from the spine differently. By answering these questions we hope to intervene in the enormous personal, social and economic consequences of LBP which affects between 60-90% of the population at some stage in their life.Read moreRead less
I am a neurophysiologist in the field of human motor control. My primary research focus is on the neural control of respiratory muscles in health and disease including obstructive sleep apnoea and spinal cord injury. I also study a number of aspects of mu
Human Muscle Stretch Reflexes: The Effects Of Stimulus Properties, Muscle State And Subject Intention
Funder
National Health and Medical Research Council
Funding Amount
$170,604.00
Summary
The best known muscle reflex is the tendon jerk, which is usually evoked by tapping the muscle tendon with a small hammer. This tap imposes a very rapid stretch on the muscle, which produces a stretch reflex. Different stretch responses, however, can be observed to slow or fast stretches, or to vibration of muscle. Normally, when the muscles of a relaxed person are stretched, no active response is observed. However, when the person is engaged in a task and contracting their muscles, then stretch ....The best known muscle reflex is the tendon jerk, which is usually evoked by tapping the muscle tendon with a small hammer. This tap imposes a very rapid stretch on the muscle, which produces a stretch reflex. Different stretch responses, however, can be observed to slow or fast stretches, or to vibration of muscle. Normally, when the muscles of a relaxed person are stretched, no active response is observed. However, when the person is engaged in a task and contracting their muscles, then stretch modulates the muscle activity such that an increase in contraction of the muscle opposes the stretch and defends the position of the joint against the external disturbance. This is the everyday situation in which stretch reflexes operate. Despite extensive investigation for over a hundred years, there is still no consensus among researchers about the behaviour of stretch reflexes nor about their role in the control of movement. Even the demarcation of reflex from voluntary muscle activity is not always certain. One of the outstanding features of stretch reflexes is the variability of their behaviour, which depends on the particular muscle involved, its level of contraction, the type of stretch and the task in which the person is engaged. This variability has made it difficult for researchers to determine the role of reflexes in the control of movement. In order to study stretch reflex behaviour in human subjects, we will measure the electrical activity of elbow muscles, the elbow position and the force generated at the joint under a variety of conditions. A series of five experiments will investigate specific unresolved issues such as the effect of subject intention on the modulation of muscle activity and how altered modulation of muscle activity may change the stiffness of our limbs. The objective of the experimental series is to fill in important gaps in the picture of the behaviour of the stretch reflex.Read moreRead less