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
The Role Of Adipokines In Modulation Of Gastric Vagal Afferent Satiety Signals
Funder
National Health and Medical Research Council
Funding Amount
$624,535.00
Summary
When we feel full after a meal it is the result of a variety of different nerve signals from the gut in response to distension of the stomach and specific nutrients. These signals are disordered in obesity and may be influenced by factors released from fat stores in the body. The aim of this project is to determine how these factors interact with gastric nerve satiety signals and thus identify targets for the pharmacological treatment of obesity.
Circadian Control Of Peripheral Gastric Satiety Signals
Funder
National Health and Medical Research Council
Funding Amount
$701,010.00
Summary
When we feel full after a meal it is the result of a variety of different nerve signals from the gut in response to distension of the stomach and specific nutrients. These signals exhibit circadian variations. The aim of this project is to determine circadian control of gastric nerve satiety signals and to determine how this is affected by obesity and what happens when you disrupt circadian rhythm. This will ultimately identify targets and treatment regimes for the pharmacological treatment of o ....When we feel full after a meal it is the result of a variety of different nerve signals from the gut in response to distension of the stomach and specific nutrients. These signals exhibit circadian variations. The aim of this project is to determine circadian control of gastric nerve satiety signals and to determine how this is affected by obesity and what happens when you disrupt circadian rhythm. This will ultimately identify targets and treatment regimes for the pharmacological treatment of obesity.Read moreRead less
Obesity is a looming health crisis for Australians; it increases the chances of many serious diseases including diabetes, cancer, stroke and heart disease. Obesity occurs when the amount of energy consumed in food is greater than the energy used over an extended period. Because human beings usually get most of their food in a few meals each day, the size of those meals is very important. Deciding when to stop eating can exert a powerful control on energy intake. It is well known that nutrients r ....Obesity is a looming health crisis for Australians; it increases the chances of many serious diseases including diabetes, cancer, stroke and heart disease. Obesity occurs when the amount of energy consumed in food is greater than the energy used over an extended period. Because human beings usually get most of their food in a few meals each day, the size of those meals is very important. Deciding when to stop eating can exert a powerful control on energy intake. It is well known that nutrients reaching the gut cause the release of hormones from cells in the lining of the stomach and intestine. These hormones tell the brain when enough food has been consumed. It used to be thought that the hormones travelled in the blood stream to affect the brain directly. Recently, it has become clear that much of their effect is actually carried by sensory neurons with endings in the lining of the gut. The hormones have a powerful effect the sensory nerve fibres which then send electrical signals in nerve fibres running in the vagus nerve to the brain. Here they make connections which eventually influence the centres that control feeding. There is much to understand about how hormones affect the sensory nerve endings in the wall of the gut, whether all nerve fibres are affected the same way and what sort of information is conveyed to the brain. This project will use electrophysiological methods to identify which nerve fibres are activated by hormones, whether different hormones affect different nerve fibres, which nutrients activate particular nerve fibres and whether nerve fibres make selective contacts with particular hormone-releasing cells. These questions are important for understanding how we normally stop feeding and how drugs might be designed to cause feelings of fullness earlier in each meal.Read moreRead less
Interactions Of Gastric Hormones With Vagal Afferent Pathways And The Role Of This System In Obesity
Funder
National Health and Medical Research Council
Funding Amount
$550,918.00
Summary
When we feel full after a meal it is the result of a variety of different nerve signals from the gut in response to distension of the stomach and specific nutrients. These signals are disordered in obesity and this project aims to find out how to correct this problem in this modern day epidemic.
Roles Of Brain-derived Neurotrophic Factor In Plasticity Of Injured Sensory Neurons
Funder
National Health and Medical Research Council
Funding Amount
$461,443.00
Summary
The fundamental problem of how nerve cells respond to a nerve injury has long been studied by neuroscientists and clinicians. After a nerve injury outside the brain or spinal cord, ie, in the periphery, some sensory nerve cells die, some regenerate to reconnect to their targets, and some sprout to make abnormal connections. Recent evidence from our lab and others indicates that the nerve sprouting is linked to chronic pain experienced by nerve-injury patients. However, how these changes occur st ....The fundamental problem of how nerve cells respond to a nerve injury has long been studied by neuroscientists and clinicians. After a nerve injury outside the brain or spinal cord, ie, in the periphery, some sensory nerve cells die, some regenerate to reconnect to their targets, and some sprout to make abnormal connections. Recent evidence from our lab and others indicates that the nerve sprouting is linked to chronic pain experienced by nerve-injury patients. However, how these changes occur still remains largely unknown. Our recent studies showed that growth factors, particularly brain-derived neurotrophic factor (BDNF) which is made by the sensory nerve cells, may play important roles in mediating these changes. This proposed project, directly evolved from our recent exciting findings, aims to further examine roles and action mechanisms of BDNF and its relatives in regulating the responses of sensory nerve cells to a nerve injury. We propose that after an injury, BDNF promotes survival of some nerve cells, enhances sensory nerve regeneration in both periphery and spinal cord, and also mediates abnormal nerve sprouting and is involved in neuropathic pain. With strong expertise and powerful tools in hand, we have designed a series of experiments to investigate the roles and action mechanisms of BDNF and its related molecules in these processes. Results from this project will help us understand mechanisms underlying the responses of nerve cells to a nerve injury, and should provide much needed information which would help in designing new methods for enhancing nerve cell survival and nerve regeneration as well as for inhibiting nerve injury-induced chronic pain in nerve-injury patients.Read moreRead less