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
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
Neural Coding Of A Cue To Auditory Space, In Noisy Environments
Funder
National Health and Medical Research Council
Funding Amount
$180,160.00
Summary
GENERAL BACKGROUND : Our ability to determine where a sound is coming from (localization ability) is severely disrupted when the environment is noisy. This affects our abilities at many ordinary tasks, such as keeping up a conversation in a noisy background, and also in other critical tasks (eg., in following warning signals in a noisy factory environment). In people who have some hearing loss, even if only partial deafness, localization ability is disrupted even when there is no noise in the ba ....GENERAL BACKGROUND : Our ability to determine where a sound is coming from (localization ability) is severely disrupted when the environment is noisy. This affects our abilities at many ordinary tasks, such as keeping up a conversation in a noisy background, and also in other critical tasks (eg., in following warning signals in a noisy factory environment). In people who have some hearing loss, even if only partial deafness, localization ability is disrupted even when there is no noise in the background, and is even more severely disrupted when the environment is noisy. SCIENTIFIC BACKGROUND : Our localization ability depends on the way neurons in the brain code the position of a source of sound we wish to detect. From studies in animals we know a lot about the way in which neurons do this coding in silence. However, we know almost nothing about how this coding is affected by a noisy background. Further, we know absolutely nothing about how this coding, whether in silence or when there is noise, is affected when there is also a hearing loss. SIGNIFICANCE : If we are to understand the effects of hearing losses on coding of the location of a sound signal we need to know first how noise affects the coding in cases of normal hearing. This project aims to gain that information. I will then extend this to studying the detailed basis of these effects, ie., exactly what mechanisms are affected in the neurons. Then I will determine how noise from different positions affects the coding of signal sounds at differnt positions. These data will provide us the essential base from which we can, later, go on to study how noise affects coding by neurons of the location of a signal. I plan to increase the value of the current study by developing, from the data gained in the studies in animals, computer-based models that will allow us to predict how coding of sound signal location is affected by hearing loss, and how this is exacerbated by noisy environments.Read moreRead less
Cortical Interactions Between Afferent Channels In Macaque Visual System
Funder
National Health and Medical Research Council
Funding Amount
$380,154.00
Summary
There are three distinct groups of cells that carry the visual information from the eyes to the brain, each pathway signaling a different aspect of the visual scene. This project will study in detail the lesser known of these three pathways (koniocellular neurones): what sort of information they carry into the brain, how it is combined with the other pathways to yield our composite picture and where in the brain such combination takes place.
Neogenin: A Regulator Of Neuronal Differentiation And Migration In The Adult Brain
Funder
National Health and Medical Research Council
Funding Amount
$334,053.00
Summary
Conditions such as Alzheimer�s and Huntington�s diseases, as well as stroke, represent a major burden of disease in Australia. One goal of modern neurobiology is to harness the brain's ability to make new neurons so that we can replace those damaged by disease or injury. We will investigate how an important developmental molecule, Neogenin, promotes the production of new neurons in the adult brain. A second goal is to show that Neogenin can be activated to promote the repair of the damaged brain ....Conditions such as Alzheimer�s and Huntington�s diseases, as well as stroke, represent a major burden of disease in Australia. One goal of modern neurobiology is to harness the brain's ability to make new neurons so that we can replace those damaged by disease or injury. We will investigate how an important developmental molecule, Neogenin, promotes the production of new neurons in the adult brain. A second goal is to show that Neogenin can be activated to promote the repair of the damaged brain.Read moreRead less
Discovering Molecules And Mechanisms Regulating Dendrite Formation
Funder
National Health and Medical Research Council
Funding Amount
$517,989.00
Summary
Dendrites are neuronal projections necessary to receive stimuli from other neurons or the external environment. Abnormalities in dendrite development associate with mental retardation and other human conditions such as Down syndrome, Rett syndrome and Fragile-X syndrome. The studies presented in this proposal, using the powerful genetic and molecular tools available for the nematode C. elegans, will provide new insight into the cellular and molecular mechanisms regulating dendrite development.
The Development Of Glial Cells In The Sympathetic Nervous System
Funder
National Health and Medical Research Council
Funding Amount
$372,025.00
Summary
Nervous system development entails the co-ordinated multiplication of a small number of founder cells to give the millions of cells of the mature nervous system. Each founder generates a many different cell types. Understanding how this is controlled is among the most challenging problems in modern biology. We will show how the development of the two basic cell types (neurons and glia), is controlled in a part of the nervous system that is relatively simple and accessible for manipulation.
Brain Adaptation Associated With Spontaneous And Training-induced Recovery Of Touch Sensation Post-stroke.
Funder
National Health and Medical Research Council
Funding Amount
$339,950.00
Summary
Brain networks may reorganize to optimise stroke recovery. However, little is known about brain mechanisms underlying natural and training-induced recovery after stroke, particularly following loss of body sensations. Knowledge of the experiences that may facilitate brain reorganisation is a prerequisite for the development and evaluation of optimal stroke rehabilitation strategies. We aim to provide novel information on the potential benefits of specific training in facilitating reorganisation ....Brain networks may reorganize to optimise stroke recovery. However, little is known about brain mechanisms underlying natural and training-induced recovery after stroke, particularly following loss of body sensations. Knowledge of the experiences that may facilitate brain reorganisation is a prerequisite for the development and evaluation of optimal stroke rehabilitation strategies. We aim to provide novel information on the potential benefits of specific training in facilitating reorganisation of the brain after stroke. Specifically we will: (i) locate areas of brain activity associated with natural and training-induced recovery of touch sensation following stroke and (ii) investigate the relationship between brain activation, sensory recovery and intervening experience. Site and extent of brain activation associated with recovery of touch sensation will be investigated over time using serial functional magnetic resonance imaging (fMRI), a controlled sensory task and clinical measures of recovery. Thirty stroke patients with impaired touch sensation of the upper limb will be studied at 2-6 weeks and 6 months post-stroke to investigate changes in brain activation associated with natural recovery (Study 1). Ten healthy controls will also be studied over 6 months. Those patients who still have sensory loss at 6 months will then receive specific sensory training or placebo intervention to study the effect of training-induced recovery on brain activity (Study 2). The whole brain will be studied and activation sites will be interpreted relative to individual and standard brain maps. We expect that the findings will advance our knowledge of the relationship between clinical recovery, training and neural plastic changes in the brain. This information will provide direction for the development of scientifically based treatments designed to maximise recovery and help identify patients who are likely to show natural recovery and-or benefit from training.Read moreRead less
Molecular Definition Of Neural Pathways In The Embryo And Adult Mouse
Funder
National Health and Medical Research Council
Funding Amount
$401,000.00
Summary
It is our objective to gain insight into the role of the Stem Cell leukaemia (SCL) gene in the central nervous system (CNS). SCL is known to play a crucial role in blood cell development and if aberrantly expressed can lead to T-cell leukemia. Although we do know that SCL is expressed in the brain, its role in the CNS has not been addressed so far and it is of great interest to us to study its potential function in neural development. We have designed a series of experiment in mice to elucidate ....It is our objective to gain insight into the role of the Stem Cell leukaemia (SCL) gene in the central nervous system (CNS). SCL is known to play a crucial role in blood cell development and if aberrantly expressed can lead to T-cell leukemia. Although we do know that SCL is expressed in the brain, its role in the CNS has not been addressed so far and it is of great interest to us to study its potential function in neural development. We have designed a series of experiment in mice to elucidate the expression pattern of SCL in the CNS, to identify the phenotype of neural cells that express SCL in different regions of the mouse brain, and to ablate the SCL gene at different time points during life (during embryonic development, just after birth and during adulthood). These experiments will be performed in conditional transgenic mice that have unique and precisely defined genetic alteration and are generated by us specifically for our research on the SCL-gene. This genetic approach is used to define the neuroanatomical and molecular bases of SCL-function in the brain.Read moreRead less