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
I am a physiologist investigating the molecular basis of normal function in skeletal muscle and the dysfunctions occurring in various muscle diseases and in fatigue. In addition, I investigate analogous dysfunction of calcium release and excitability occu
Intrauterine Growth Restriction And Development Of The Peripheral And Coronary Vasculature
Funder
National Health and Medical Research Council
Funding Amount
$437,176.00
Summary
There have been no studies which have investigated the extent to which fetal substrate restriction and associated fetal growth restriction alter the expression of nerve growth factors which determine the extent of sympathetic innervation of the peripheral vasculature and the interaction of changes within the peripheral and coronary vasculature which may explain the association between fetal growth restriction and the emergence of cardiovascular disease and high blood pressure in later life. Thes ....There have been no studies which have investigated the extent to which fetal substrate restriction and associated fetal growth restriction alter the expression of nerve growth factors which determine the extent of sympathetic innervation of the peripheral vasculature and the interaction of changes within the peripheral and coronary vasculature which may explain the association between fetal growth restriction and the emergence of cardiovascular disease and high blood pressure in later life. These studies ill provide new insights into the lifelong cardiovascular sequelae of a suboptimal intrauterine environment.Read moreRead less
Establishing STARS As A Therapeutic Target To Reduce Muscle Wasting And Improve Muscle Function
Funder
National Health and Medical Research Council
Funding Amount
$446,189.00
Summary
Muscle wasting occurs rapidly with disuse after injuries occurring at work, during sport, with chronic disease and in road accidents. It is also a consequence of ageing. Muscle wasting and reduced muscle function places considerable financial strain on our health care system. We aim to use gene therapy and pharmacological interventions to increase the levels of a protein called STARS. We hypothesize that STARS will reduce disuse-induced muscle wasting, increase recovery and improve function.