How Changes In The Motor Cortex And Spinal Cord With Exercise Contribute To Fatigue In Humans
Funder
National Health and Medical Research Council
Funding Amount
$311,250.00
Summary
Fatigue with exercise is a common experience in healthy people and can be a problem in many illnesses. With fatigue people are less able to produce force with their muscles. Much of this weakness occurs because of events in the muscles but some results from changes in the nervous system. The size of the contribution of the nervous system to fatigue is not known for the kinds of exercise that cause fatigue in everyday life e.g. prolonged weak contractions like holding the shopping or a plate of f ....Fatigue with exercise is a common experience in healthy people and can be a problem in many illnesses. With fatigue people are less able to produce force with their muscles. Much of this weakness occurs because of events in the muscles but some results from changes in the nervous system. The size of the contribution of the nervous system to fatigue is not known for the kinds of exercise that cause fatigue in everyday life e.g. prolonged weak contractions like holding the shopping or a plate of food, rhythmic contractions like walking or painting a wall, and more vigorous exercise that causes changes in breathing and body temperature. The behaviour of nerve cells in the brain and spinal cord is altered in fatigue but how and why many of these changes occur, and how they affect the control of movements, is poorly understood. Three approaches are planned. In the first set of studies, we will use brain and nerve stimulation to measure the impact of sustained low-level activities on people's ability to drive their muscles fully. We will identify whether such activities, as well as increased demands on other body systems, can cause fatigue in the nervous system. In the second set of studies, we will investigate whether changes in the motor areas of the brain can alter peoples' performance of fatiguing motor tasks or their perception of how much effort the tasks take. Finally, we will use stimulation of the spinal cord to work out why motor nerve cells in the spinal cord fire more slowly with fatigue. Fatigue is an important symptom which is not confined to diseases of any one system in the body. For example, it is a major complaint in multiple sclerosis, cardiac failure, chronic obstructive airway disease, depression and cancer, as well as after chemotherapy, surgery, and viral illness. The implications of better understanding of the contribution of the nervous system to fatigue range from targeting treatments in patients to improving the performance of athletes.Read moreRead less
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
Revealing the beneficial effects of acoustic stimulation on the human brain. This project aims to provide greater understanding of the neural mechanisms by which initiation of motor responses can be improved by unexpected auditory stimulation. Initiating motor actions appears natural and effortless, but is underpinned by complex neural mechanisms that are not well understood. Using novel brain stimulation techniques, the project aims to assess the potential for properly timed strong sensory stim ....Revealing the beneficial effects of acoustic stimulation on the human brain. This project aims to provide greater understanding of the neural mechanisms by which initiation of motor responses can be improved by unexpected auditory stimulation. Initiating motor actions appears natural and effortless, but is underpinned by complex neural mechanisms that are not well understood. Using novel brain stimulation techniques, the project aims to assess the potential for properly timed strong sensory stimulation during movement preparation to induce neural plasticity and motor learning. This knowledge would have important implications across a number of fields, including neuroscience, sports science, and applied ergonomics.Read moreRead less
Discovery Early Career Researcher Award - Grant ID: DE120100653
Funder
Australian Research Council
Funding Amount
$375,000.00
Summary
The predictive brain and control of anticipatory actions. The ability to predict events in a dynamic environment is an important skill for survival as it can guide our actions when time pressures are severe. How predictions come about to guide our actions is not clear and project results will have great theoretical significance to understand how we generate them.
Cortical, Descending And Reflex Control Of Human Inspiratory Muscles
Funder
National Health and Medical Research Council
Funding Amount
$324,500.00
Summary
Of all the skeletal muscles, the breathing muscles perform the most crucial action, that is, they maintain ventilation. The neural control of respiratory muscles must be finely integrated to maintain ventilation while we are awake, asleep, exercising, eating and talking. The neural circuitry for the respiratory muscles is unique. Control of respiratory muscles differs from that of limb muscles because the respiratory motoneurones are activated rhythmically but are controlled via two descending p ....Of all the skeletal muscles, the breathing muscles perform the most crucial action, that is, they maintain ventilation. The neural control of respiratory muscles must be finely integrated to maintain ventilation while we are awake, asleep, exercising, eating and talking. The neural circuitry for the respiratory muscles is unique. Control of respiratory muscles differs from that of limb muscles because the respiratory motoneurones are activated rhythmically but are controlled via two descending pathways. During automatic breathing, descending neural drive arises from the central respiratory pattern generator in the brainstem. Through this system, disturbances are reflexly compensated for without conscious effort. However, in addition, to automatic control, respiration can also be controlled voluntarily from the motor cortex, for example during speech or a breath hold. However, in humans the neural connections and interactions between these two centres are poorly understood. In addition to descending signals, the activity of inspiratory muscles is affected by sensory reflex inputs. The proposed studies will investigate three aspects of the control of human inspiratory muscles that act to 'pump' air into the lungs and upper airway 'dilator' muscles that act to keep the airway open. Because expiration is usually passive during quiet breathing we will focus on the neural control of inspiration. First, we will investigate some of the reflex connections of human 'pump' and 'dilator' muscles in people with and without obstructive sleep apnoea. Second, we will study the descending control of inspiratory muscles using single motor unit recordings. In addition, we will make the first detailed analysis of single motor unit activity from the tongue. This muscle critically helps preserve breathing when we sleep. Finally, we will examine the interactions between the motor cortex and medulla in the control of breathing about which relatively little is known in awake humans.Read moreRead less
The genetic and diagnostic relationship between motor control and Attention Deficit Hyperactivity Disorder. Children with Attention Deficit Hyperactivity Disorder (ADHD) often have comorbid Developmental Coordination Disorder (DCD). This project will utilise the expertise of leading researchers in Australia and the Netherlands to investigate the genetic and diagnostic relationship between these two disorders utilising a large sample of twins and their siblings. We will examine the neuropsych ....The genetic and diagnostic relationship between motor control and Attention Deficit Hyperactivity Disorder. Children with Attention Deficit Hyperactivity Disorder (ADHD) often have comorbid Developmental Coordination Disorder (DCD). This project will utilise the expertise of leading researchers in Australia and the Netherlands to investigate the genetic and diagnostic relationship between these two disorders utilising a large sample of twins and their siblings. We will examine the neuropsychological functioning in these groups of children in order to gain a better understanding of their genetic relationship. These findings will provide insight into the current DSM-IV classification of these disorders compared with other models used to investigate the relationship between poor motor coordination and ADHD.Read moreRead less
Functional Assessment of Head-eye Coordination during Driving. 238 people per 100,000 population were hospitalized and 9 people per 100,000 died as a result of road-transport related injury in Australia in 2002. We will address this issue by assessing the head eye coordination strategies for young drivers, for proficient drivers and for aged drivers to determine those behaviors and strategies that are associated with various levels of performance. This insight could be affectively communicated t ....Functional Assessment of Head-eye Coordination during Driving. 238 people per 100,000 population were hospitalized and 9 people per 100,000 died as a result of road-transport related injury in Australia in 2002. We will address this issue by assessing the head eye coordination strategies for young drivers, for proficient drivers and for aged drivers to determine those behaviors and strategies that are associated with various levels of performance. This insight could be affectively communicated to others and would provide the basis for educational material and methods that would improve operator skill, safety, and performance. These individual improvements would provide overall benefits such as improved transport efficiency, reduced accident rates, saved lives and a reduction in related social costs.Read moreRead less
How brain oscillations influence our behaviour. This project aims to reveal how sudden, intense stimuli impair or facilitate concurrent actions. Startling sounds can disrupt the execution of movements and distract attention from vital events in the environment, with potential disastrous consequences when handling complex equipment such as airplanes, cars and trucks, or surgical instruments. This project will combine classic experimental and novel neuro-modulatory techniques with the measurement ....How brain oscillations influence our behaviour. This project aims to reveal how sudden, intense stimuli impair or facilitate concurrent actions. Startling sounds can disrupt the execution of movements and distract attention from vital events in the environment, with potential disastrous consequences when handling complex equipment such as airplanes, cars and trucks, or surgical instruments. This project will combine classic experimental and novel neuro-modulatory techniques with the measurement of oscillatory brain activity. Expect outcomes will inform theories of cognitive function and the design of interventions to reduce the negative effects of sudden, distracting events.Read moreRead less
Intracortical inhibition evaluated by paired-pulse TMS during choice and simple reaction time tasks. The research will investigate the neurophysiological processes responsible for the selection and initiation of movement in response to an external stimulus. Slowness in the initiation and execution of movement is a common feature of 'neurological aging', neurodegenerative disease, and brain injury. Understanding the brain mechanisms involved in response selection and movement initiation will pro ....Intracortical inhibition evaluated by paired-pulse TMS during choice and simple reaction time tasks. The research will investigate the neurophysiological processes responsible for the selection and initiation of movement in response to an external stimulus. Slowness in the initiation and execution of movement is a common feature of 'neurological aging', neurodegenerative disease, and brain injury. Understanding the brain mechanisms involved in response selection and movement initiation will provide information for the development of specific intervention techniques to improve motor function in these groups.Read moreRead less