We are able to identify and discriminate objects in the world because of exquisitely detailed and rapid processing of sensory information by neurons in the cortex of the brain. In this project we will examine these operations in neurons in the cortex that receive input from the large face whiskers of the rat. These whiskers are used for fine-grain discrimination and for gauging distance. They are deflected by being actively moved, under muscle control, over objects (active touch) or by being pas ....We are able to identify and discriminate objects in the world because of exquisitely detailed and rapid processing of sensory information by neurons in the cortex of the brain. In this project we will examine these operations in neurons in the cortex that receive input from the large face whiskers of the rat. These whiskers are used for fine-grain discrimination and for gauging distance. They are deflected by being actively moved, under muscle control, over objects (active touch) or by being passively deflected by objects. Deflection results in inputs to the brain that are processed to form the neural basis for very finely detailed perceptual behaviour. In rats, with impoverished visual and auditory senses, the whiskers are the major sensory system for interacting with the world, and are used in navigating the environment and in finding and distinguishing foods. Thus they contribute strongly to the remarkable success of this species. This elegant sensory system has a number of advantages that make it a very good model for the study of brain mechanisms responsible for active fine-grain sensory function. We plan to take advantage of the unique features of this system to define the information processing that occurs in the cortex in this elegantly complex system. This will address an issue relevant to all sensory systems - namely the neural basis of complex fine grain perceptual behaviour. Understanding the mechanisms underlying active tactile perception also has relevance to clinical conditions involving deficits in active touch e.g., in diabetic polyneuropathy (which eventually affects ~50% of diabetics), in leprosy (in which an early sign is damage to active touch). Knowledge of the core brain processes in active touch gained in this study could eventually underpin the ameliorative technologies for such deficits.Read moreRead less
How Does Chronic Epilepsy Result In Cardiac Electrophysiological Dysfunction?
Funder
National Health and Medical Research Council
Funding Amount
$737,112.00
Summary
Cardiac dysfunction is common in epilepsy, and could be an important contributor to the increased risk of sudden death in people with epilepsy (SUDEP). In this grant we will investigate: when changes in the cardiac function develop in relation to the epilepsy; if people with chronic epilepsy have similar changes; and what effect seizures and epilepsy has on the nerves innervating the heart. The outcomes have the potential to motivate new treatments and prevention for this important problem.
Sensory Coding Mechanisms in Rat Somatosensory System; A Combined Behavioural and Electrophysiological Approach. This inter-disciplinary project spans behavioural sciences, neurophysiology and computational neuroscience. It investigates fundamental questions such as how different aspects of stimuli are presented in sensory areas of the brain and how the animal interprets the neuronal activity in such areas to generate the relevant behaviour. A major problem with making prosthetic sensory devices ....Sensory Coding Mechanisms in Rat Somatosensory System; A Combined Behavioural and Electrophysiological Approach. This inter-disciplinary project spans behavioural sciences, neurophysiology and computational neuroscience. It investigates fundamental questions such as how different aspects of stimuli are presented in sensory areas of the brain and how the animal interprets the neuronal activity in such areas to generate the relevant behaviour. A major problem with making prosthetic sensory devices is the way by which these devices can communicate with the brain. Research into the coding of different features of simple stimuli will provide basic knowledge which can be implemented in prosthetic sensory devices. Read moreRead less
Understanding Cortical Circuitry Underlying Sensory Integration And The Consequence Of Its Developmental Disruption
Funder
National Health and Medical Research Council
Funding Amount
$527,395.00
Summary
The mammalian neocortex is organised into six layers with a systematic pattern of wiring that relies on normal development and balanced activity of neurons. This project combines developmental, electrophysiological, optogenetic behavioural, and computational methods to establish how the properties of the precise structure of cortical circuits impact their function and how disruptions in the balanced activity during development affect circuit formation and function in the mature brain.
Optimising And Applying Ocular Vestibulat Evoked Myogenic Potentials (oVEMPs)
Funder
National Health and Medical Research Council
Funding Amount
$228,931.00
Summary
This project seeks to optimise techniques for a new method of assessing the balance organs (vestibular organs) and then apply these techniques. Three conditions will be studied: vestibular neuritis - a condition causing acute and severe dizziness; Parkinson's disease, in which disorders of balance are common and superior canal dehiscence (SCD) in which there is a hole in the bone overlying one of the semicircular canals, leading to sensitivity to sound.
Chromatic Inputs to Cortical Receptive Fields in Primates. The human eye contains three kinds of receptors for daytime vision, named blue, green and red cones for their sensitivity to different regions of the visible spectrum. It is known that blue cones contribute to brain pathways for colour vision, but recent data suggest there is also 'cross-talk' of blue cone signals to pathways for motion and high-acuity vision. This project comprises precise measurement of blue cone signals, and anatomica ....Chromatic Inputs to Cortical Receptive Fields in Primates. The human eye contains three kinds of receptors for daytime vision, named blue, green and red cones for their sensitivity to different regions of the visible spectrum. It is known that blue cones contribute to brain pathways for colour vision, but recent data suggest there is also 'cross-talk' of blue cone signals to pathways for motion and high-acuity vision. This project comprises precise measurement of blue cone signals, and anatomical tracing of blue cone pathways, in a primate model for human vision. The data will improve our basic knowledge of how the brain processes sensory signals.Read moreRead less
Neuronal Activity And Functional Magnetic Resonance Imaging (fMRI)
Funder
National Health and Medical Research Council
Funding Amount
$367,561.00
Summary
How does brain activity relate to perception and behaviour? How does functional magnetic resonance imaging (fMRI) of the brain, which measures changes in blood oxygen, relate to the activity of single cells? I will address these questions, comparing electrical measurements of single cells and functional images, and advance our understanding of the brain in health and disease.
The Claustrum Enigma: Unlocking The Role Of The Last Unknown Area Of The Primate Brain
Funder
National Health and Medical Research Council
Funding Amount
$558,364.00
Summary
Despite nearly 200 years of study, the function of the claustrum remains unclear. Interest in this brain structure has recently been revived by findings showing damage to the claustrum in several major diseases, and by the suggestion that the claustrum may have a role in consciousness. Here we propose a series of experiments to test the novel hypothesis that the claustrum is part of the default mode network, a group of brain areas that act together when we aren't thinking about anything in parti ....Despite nearly 200 years of study, the function of the claustrum remains unclear. Interest in this brain structure has recently been revived by findings showing damage to the claustrum in several major diseases, and by the suggestion that the claustrum may have a role in consciousness. Here we propose a series of experiments to test the novel hypothesis that the claustrum is part of the default mode network, a group of brain areas that act together when we aren't thinking about anything in particular, that is- most of the time.Read moreRead less
Improving Oral health is a priority of the NHMRC Strategic Plan 2003-06. The proposed research is consistent with this priority as we will achieve a better understanding of the cortical control of human jaw muscles, which serves as the foundation for understanding conditions in which their function is impaired, and the development of rational therapies for these conditions. Transcranial magnetic stimulation will be used to activate the motor cortex and corticobulbar descending pathway to the jaw ....Improving Oral health is a priority of the NHMRC Strategic Plan 2003-06. The proposed research is consistent with this priority as we will achieve a better understanding of the cortical control of human jaw muscles, which serves as the foundation for understanding conditions in which their function is impaired, and the development of rational therapies for these conditions. Transcranial magnetic stimulation will be used to activate the motor cortex and corticobulbar descending pathway to the jaw muscles. The AIM 1 study will provide important new information about the functional organisation of the motor cortex in the control of jaw muscles during speech. This information is needed to improve understanding of dysarthria, a common disturbance of speech due to impaired muscular control following unilateral cortical stroke, and less common conditions involving speech motor control such as spasmodic dysphonia (a cranial dystonia) and dysprosody (disturbance of speech articulation and rhythm found in Parkinson s disease). The AIM 2 and 3 studies will provide a comprehensive characterization of cortical inhibitory mechanisms that are an important but poorly understood component of the cortical control of jaw muscles. This information is necessary to understand normal function, and the mechanisms of disturbances to jaw muscle function with neurological disease or injury. The AIM 4 studies will show whether impaired cortical inhibition contributes to the pathophysiology of two poorly understood disorders affecting jaw muscles (bruxism and oromandibular dystonia). Current therapies for these conditions are unsatisfactory, due to a limited understanding of the mechanisms involved. If cortical inhibition is abnormal in these conditions this will lead to novel treatment therapies (e.g., drugs to correct the imbalance, or strategies to induce plastic change in the cortex).Read moreRead less
Is EphA4 The Major Molecular Regulator Of Axonal Regeneration?
Funder
National Health and Medical Research Council
Funding Amount
$491,000.00
Summary
Spinal cord injury affects a substantial number of Australians each year. Around half the number of spinal cord injury cases result in quadriplegia, with loss of function to a varying degree in the upper as well as the lower limbs. The limited degree of repair of spinal axons following injury means that such paralysis is usually permanent. Although the inability to walk is a serious issue, the limited function of the arms and hands results in a loss of independence which is a major factor contri ....Spinal cord injury affects a substantial number of Australians each year. Around half the number of spinal cord injury cases result in quadriplegia, with loss of function to a varying degree in the upper as well as the lower limbs. The limited degree of repair of spinal axons following injury means that such paralysis is usually permanent. Although the inability to walk is a serious issue, the limited function of the arms and hands results in a loss of independence which is a major factor contribuing to the enormous personal, financial, and community costs of this problem, estimated to cost the Australian community $200 million a year. In recent years advanced anatomical and molecular approaches to the problem of repair of the central nervous system have provided great insights into the neuronal and glial reactions to neural damage that appear to govern the success or failure of neural regeneration. Our preliminary data indicate that a receptor tyrosine kinase, EphA4, which is important for axonal pathfinding in the developing nervous system, is a potent inhibitor of neural regeneration following spinal cord injury. In this project we will determine the mechanisms by which EphA4 exerts its inhibitory effects, and examine the effect of neutralizing EphA4 signalling on neural regeneration. Success in achieving this result will lead to the development of a therapeutic intervention that we will test in mouse models.Read moreRead less