Deciphering The Mechanisms For Constructing The Olfactory System
Funder
National Health and Medical Research Council
Funding Amount
$496,321.00
Summary
The olfactory (smell) system is a unique part of the nervous system; nerve cells are generated throughout life and it can regenerate even after injury. It therefore provides an excellent model for examining the growth, development and maintenance of nerve cells. This project will examine the effects on the organisation of the olfactory system when some guidance signals are altered. Information we obtain about how this system develops and regenerates may be useful in treating brain disorders and ....The olfactory (smell) system is a unique part of the nervous system; nerve cells are generated throughout life and it can regenerate even after injury. It therefore provides an excellent model for examining the growth, development and maintenance of nerve cells. This project will examine the effects on the organisation of the olfactory system when some guidance signals are altered. Information we obtain about how this system develops and regenerates may be useful in treating brain disorders and spinal injuries The results of these experiments will provide important information on the the initial growth and targeting of these nerve cells which may have implications for regeneration of these as well as other nerve cells.Read moreRead less
Understanding The Role Of The Olfactory Ensheathing Cell In The Olfactory Sensory System
Funder
National Health and Medical Research Council
Funding Amount
$494,000.00
Summary
The olfactory (smell) system is a unique part of the nervous system; nerve cells are generated throughout life and it can regenerate even after injury. It therefore provides an excellent model for examining the growth, development and maintenance of nerve cells. This project will examine how one specialized type of cell, the olfactory ensheathing cell, helps the nerve cells to grow and regenerate. Information we obtain about how this system develops and regenerates may be useful in treating brai ....The olfactory (smell) system is a unique part of the nervous system; nerve cells are generated throughout life and it can regenerate even after injury. It therefore provides an excellent model for examining the growth, development and maintenance of nerve cells. This project will examine how one specialized type of cell, the olfactory ensheathing cell, helps the nerve cells to grow and regenerate. Information we obtain about how this system develops and regenerates may be useful in treating brain disorders and spinal injuries In the current project we will examine how olfactory nerve cells interact with the ensheathing cells. We will use transgenic mice in which the different cells are marked by separate colours which will allow us to easily identify the cells and see where they grow. In addition, we will also examine the behaviour of live cells as they are growing. In the past all attempts to understand how nerve cell connections are formed in the olfactory system have used dead tissue that has been permanently preserved. In this project we have the unique opportunity to visualise living nerve cells to enable us to determine how the cells interact with the ensheathing cells. The advantage of this approach is that it allows us to identify important interactions as they occur, rather than attempting to decipher them after they have occurred. An analogy would be watching a football game live and observing how goals were scored and appreciating the performance of individual players versus trying to guess from the final score how the game was played and who the key performers were. These experiments will provide important information about how the olfactory ensheathing and nerve cells grow and regenerate.Read moreRead less
Much of the human brain is devoted to vision, which requires the integrated activity of many interconnected areas of the cerebral cortex. Damage to these areas is a relatively common complication of preterm delivery and- or perinatal conditions including trauma and infection. The severity of both the short- and long-term effects of these lesions appears to be related to the time of the damage. The aim of this project is to investigate the way in which the multiple visual areas of the brain devel ....Much of the human brain is devoted to vision, which requires the integrated activity of many interconnected areas of the cerebral cortex. Damage to these areas is a relatively common complication of preterm delivery and- or perinatal conditions including trauma and infection. The severity of both the short- and long-term effects of these lesions appears to be related to the time of the damage. The aim of this project is to investigate the way in which the multiple visual areas of the brain develop and become 'wired' together in the period following birth. We will also determine if there are mechanisms which allow alternate routes to be found for processing visual information while the brain is still establishing connections between its multiple areas. This will allow us to understand the anatomical and physiological bases of the deficits caused by early damage to the visual areas of the brain, and perhaps point to strategies that will lead to improved recovery of visual function.Read moreRead less
High Speed Video To Assess Eye Movements In Vestibular Dysfunction - A Validation Study
Funder
National Health and Medical Research Council
Funding Amount
$133,351.00
Summary
Dizziness affects a third of the population during their lives. Abnormal eye movements are often the best guide as to what has gone wrong in the dizzy person. The problem is that these eye movements can be difficult to see, and hence measure, as a way of diagnosing and then treating the dizziness. Video-oculography holds great promise for helping doctors identify the cause, and in many cases offer simple curative treatment, for dizziness.
The Role Of Dopamine And Other Neuromodulators As Light Signals In The Inner Retina: A Link To Night Blindness Disorders
Funder
National Health and Medical Research Council
Funding Amount
$250,250.00
Summary
Although most human activities can be performed at night as efficiently as during daytime due to the use of artificial light, normal function of the circuits underlying night vision is critical. For example, when driving at night in a poorly illuminated road where the region illuminated by the headlights is processed by the cone circuit that serves daylight in the retina whilst the peripheral areas are processed by the rod driven nighttime circuit. Impairment of night vision and of the dark-ligh ....Although most human activities can be performed at night as efficiently as during daytime due to the use of artificial light, normal function of the circuits underlying night vision is critical. For example, when driving at night in a poorly illuminated road where the region illuminated by the headlights is processed by the cone circuit that serves daylight in the retina whilst the peripheral areas are processed by the rod driven nighttime circuit. Impairment of night vision and of the dark-light switch can have fatal consequences. Night blindness is a symptom characterised by reduced vision in the dark and slow adaptation to dim light. Some congenital night blindness disorders are caused by mutations in the photoreceptor calcium channels which mediate signal transmission. Additionally, patients treated with neuroleptics, a group of drugs which affect the dopaminergic system, suffer night vision disorders. Dopamine acts as a light signal in the retina. AII amacrine cells are pivotal neurones for night vision segregating two channels (ON and OFF) which convey visual information. AII cells are modulated by dopamine and thus, represent interesting targets to study the role of dopamine in the dark-light switch. Much is know about the action of dopamine on transmission of ON signals channelled by AII cells. However, its action on the OFF channel is largely unknown. We believe that some night vision disorders originate by imbalance in the dopaminergic system in the retina and its effects on AII cells. We will test our hypothesis by studying the modulatory effect of dopamine on calcium dependent signal transmission between AII cells and their partners in the OFF channel. Our hypothesis will be further tested by using animal models in which dopamine receptor function is altered. The results of these studies will provide us with an invaluable model to understand the physiological basis of the dark-light switch and of the role of dopamine in night vision disorders.Read moreRead less
Dizziness, vertigo, and imbalance affect nearly half the population by the age of 60 and balance-related falls, especially in the elderly, are a serious health concern. Surveys of primary care doctors have shown that dizziness and vertigo are as prevalent as hypertension and angina, and approximately 40% of the population experience dizziness severe enough to seek medical attention. Unfortunately, most symptoms are not relieved by currently available medical treatment. There is, however, a remar ....Dizziness, vertigo, and imbalance affect nearly half the population by the age of 60 and balance-related falls, especially in the elderly, are a serious health concern. Surveys of primary care doctors have shown that dizziness and vertigo are as prevalent as hypertension and angina, and approximately 40% of the population experience dizziness severe enough to seek medical attention. Unfortunately, most symptoms are not relieved by currently available medical treatment. There is, however, a remarkable hidden reserve of 'self-repair' in the balance system that can be triggered under certain conditions. We call this process 'vestibular compensation' and if we can understand those conditions and discover the means by which this reserve affects the nervous system, we may be able harness its power to alleviate the all distressing symptoms of imbalance. Perhaps we may even be able to apply these principles to other critical systems that may need repair. We propose to look at a key region in the central nervous system that is responsible for processing balance signals and may be very important in 'vestibular compensation'. We will try to activate this recovery process under controlled conditions so that we can understand the changes that occur. Specifically we will examine the role of vestibular (balance) neurons in the central nervous system that appear to be modified following trauma of the inner ear balance organs. We will use our new recording techniques to examine these vestibular neurons to see how their intrinsic properties may change and what external or internal factors influences this change. Our aim is to understand what factors promote and what factors inhibit full recovery.Read moreRead less
Our vestibular system provides us with the important sense of balance. When it fails we suffer debiltating bouts of vertigo and dizziness. A great deal is known about how balance signals are sent from the inner ear to our brains, but virtually nothing is known about the important signals the brain sends to the inner ear. In this study we will use a new perparation develped in our laboratory to examine how these essential brain signals control the function of our balance organs.
Functional Anisotropies In The Processing Of Orientation And Direction-of-motion By Human Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$366,164.00
Summary
We will study patterns of activity in the human brain to identify the cortical signature of normal visual function. The correspondences between patterns of brain activity and the structure and motion of the visual image in the normal human brain will provide data against which brain activity in a range of disorders from amblyopia to schizophrenia can be assessed.
The human brain has many subdivisions (�areas�) that are dedicated to vision, but in many cases their functions remain unclear. This project will study an area located deep in the brain, about which very little is known, and which appears to be affected from early stages in conditions such as Alzheimer�s disease. By understanding the patterns of electrical activity of cells in this region, and their connections with other brain areas, we hope to decipher their contribution to sensory cognition.
In the areas of the brain where visual information is processed, cells respond to the presentation of visual stimuli by changing their pattern of electrical activity. At the first level of analysis, the primary visual cortex (V1), individual cells become active only if line segments or borders of a particular orientation are present in their field of detection, which encompasses a small part of the visual scene. Cells in other visual cortical areas (the extrastriate cortex) perform more complex ....In the areas of the brain where visual information is processed, cells respond to the presentation of visual stimuli by changing their pattern of electrical activity. At the first level of analysis, the primary visual cortex (V1), individual cells become active only if line segments or borders of a particular orientation are present in their field of detection, which encompasses a small part of the visual scene. Cells in other visual cortical areas (the extrastriate cortex) perform more complex detection tasks in comparison with those in V1, which demand integration of information coming from much larger portions of the visual scene. One example of these more complex properties is the phenomenon of long-range contour integration, where our visual system groups individual line segments having similar orientations, so that they are perceived as part of the same contour. This property is reflected in the electrical responses of cells in the dorsomedial visual area (DM). How are properties such as orientation specificity and long-range contour integration created? To begin addressing this question, we will investigate correlations between the physiological properties of identified cells, the spatial distribution of their information collecting regions (dendrites), and the anatomical pathways by which they receive information from other parts of the brain. This is a basic science study aimed at determining the extent to which the anatomical structure of the brain helps define the function of individual cells and brain areas. Its primary benefit will be to increase our understanding of the mechanisms underlying all sensory processing in the brain. The knowledge obtained may also lead to developments in areas of applied research including medicine and cognitive science (for example, understanding how the brain learns to interpret visual information in early life, and how visual processing degrades with ageing).Read moreRead less