Modulating Retinal Glutamate Transport In Health And Disease
Funder
National Health and Medical Research Council
Funding Amount
$256,527.00
Summary
Damage can occur to nervous tissues like the retina and brain when there is a reduction in the blood supply. This can occur as a result of a blood clot, stroke or the eye disease, glaucoma. These conditions often result in blindness. Much of the neuronal damage is due to the release of an excess of glutamate. Glutamate is a chemical (neurotransmitter) that nerves use to communicate with each other, but it is toxic to nerves when present at high concentrations. This project will investigate the m ....Damage can occur to nervous tissues like the retina and brain when there is a reduction in the blood supply. This can occur as a result of a blood clot, stroke or the eye disease, glaucoma. These conditions often result in blindness. Much of the neuronal damage is due to the release of an excess of glutamate. Glutamate is a chemical (neurotransmitter) that nerves use to communicate with each other, but it is toxic to nerves when present at high concentrations. This project will investigate the mechanisms that regulate the concentration of glutamate in the retina. If these mechanisms could be made to work more efficiently, they may prevent the build-up of the glutamate and therefore prevent damage to the nerve cells. Understanding these mechanisms will aid in the development of an effective treatment to prevent blindness when there is a blockage of the blood supply to the retina.Read moreRead less
Retinal Endothelial Cell Changes That Precede Retinal Vein Occlusion And The Retinal Extracellular Space Changes That Follow It
Funder
National Health and Medical Research Council
Funding Amount
$118,121.00
Summary
Dr. Min Hye Kang, at The University of Western Australia, is investigating microscopic blood vessel changes that precede the onset of devastating blindness. She is also studying functional changes that occur in the retina following deprivation of its blood supply. Her research has significantly improved our understanding of cellular mechanisms that lead to blindness. It has also aided in the development of new treatment strategies for the prevention of vision loss.
INTRARETINAL OXYGEN CONSUMPTION AND THE PREVENTION OF HYPOXIA IN RETINAL ISCHEMIA
Funder
National Health and Medical Research Council
Funding Amount
$164,444.00
Summary
Adequate oxygen supply to the retina is critical for normal visual function. The oxygen is normally supplied by the blood flowing in the two circulations that support the retina. These are the choroidal circulation, lying behind the retina, and the retinal circulation, which supports the front half of the retina. The retinal circulation is particularly vulnerable to vascular disease and insufficient blood flow (ischemia). Vascular changes are involved in a wide range of retinal diseases which ar ....Adequate oxygen supply to the retina is critical for normal visual function. The oxygen is normally supplied by the blood flowing in the two circulations that support the retina. These are the choroidal circulation, lying behind the retina, and the retinal circulation, which supports the front half of the retina. The retinal circulation is particularly vulnerable to vascular disease and insufficient blood flow (ischemia). Vascular changes are involved in a wide range of retinal diseases which are currently responsible for the majority of new blindness in our community. The choroidal circulation is relatively robust, and offers a potential avenue for increasing oxygen delivery to the retina in the clinical management of ischemic retinal diseases. The feasibility of such an approach is strongly dependent on the oxygen requirements of the retina, and how this is influenced by retinal ischemia. We plan to find out how much oxygen is consumed by the many different layers within the retina under normal conditions and then determine how this changes under ischemic conditions. We will then see if we can supply enough oxygen from the choroid by a combination of raising the oxygen content of the blood, increasing choroidal blood flow, and reducing the amount of oxygen used by the outer half of the retina. Our experiments will be done in laboratory rats, but the same principles are readily transferable to humans if they prove to be beneficial in protecting the retina from ischemic damage. Our study will also quantify the relationship between oxygen levels in the blood stream, and those in the different layers of the retina. This information may prove valuable in the treatment and the prevention of other retinal diseases where the manipulation of the intraretinal oxygen environment is an exciting new avenue of research.Read moreRead less
The Functional Basis Of Direction Selectivity In The Retina
Funder
National Health and Medical Research Council
Funding Amount
$376,320.00
Summary
Motion is an everday visual experience, and in this project we are attempting to explain how our brains are able to detect the direction in which an object is moving. Surprisingly this is first accomplished within the retina, the light-sensitive system of neurons at the back of the eye. Thus the eyes are able to tell the brain in which direction an object is moving. So the question becomes, how do the eyes do it? We know that there is a special class of neurons, the direction-selective ganglion ....Motion is an everday visual experience, and in this project we are attempting to explain how our brains are able to detect the direction in which an object is moving. Surprisingly this is first accomplished within the retina, the light-sensitive system of neurons at the back of the eye. Thus the eyes are able to tell the brain in which direction an object is moving. So the question becomes, how do the eyes do it? We know that there is a special class of neurons, the direction-selective ganglion cells, which are able to detect the direction of image motion. The activity of these cells is increased by excitatory connections and reduced by so-called inhibitory connections. This project aims to identify the neural origin of the inhibitory connections, and discover how the excitation and inhibition work together to compute the direction of motion.Read moreRead less
Generation Of Complex Responses In Retinal Ganglion Cells
Funder
National Health and Medical Research Council
Funding Amount
$490,500.00
Summary
The retinal ganglion cells, whose axons form the optic nerve, comprise numerous distinct types, which respond to visual stimuli in either a simple or complex manner. The project will investigate how the complex responses of the direction-selective ganglion cells (DSGCs) and the local-edge-detector ganglion cells (LEDs) are generated. It appears that the retinal neurons providing inhibitory input to DSGCs and LEDs use different neurotransmitters, and the project will investigate how this shapes t ....The retinal ganglion cells, whose axons form the optic nerve, comprise numerous distinct types, which respond to visual stimuli in either a simple or complex manner. The project will investigate how the complex responses of the direction-selective ganglion cells (DSGCs) and the local-edge-detector ganglion cells (LEDs) are generated. It appears that the retinal neurons providing inhibitory input to DSGCs and LEDs use different neurotransmitters, and the project will investigate how this shapes the response properties of the ganglion cells. This will be done both by recording the visually evoked responses of the ganglion cells in an isolated preparation of the retina and by using two-photon laser-scanning microscopy to functionally image the neuronal interactions between the neurons that inhibit the DSGCs.Read moreRead less
Multidimensional Coding Of Visual Information In The Retina
Funder
National Health and Medical Research Council
Funding Amount
$359,431.00
Summary
Although both the retina and visual cortex are part of the central nervous system, the coding of visual information in the two laminar structures differs markedly in that all three dimensions of the cortical sheet are used to code multiple response axes but only one dimension of the retinal sheet. This project examines how visual response properties are mapped through the depth of the retina and this will provide a comparatively simple paradigm of complex information processing in the brain.
The Cellular Organisation Of Interneurones In Human Retina
Funder
National Health and Medical Research Council
Funding Amount
$526,454.00
Summary
Our goal is to determine the numbers and types of nerve cells in the human retina: the part of the eye where visual processing starts. This data will serve as a baseline against which effects of visual disease can be measured.
Glial-neuronal-vascular Interactions In A Novel Transgenic Model Of Muller Cell Dysfunction
Funder
National Health and Medical Research Council
Funding Amount
$626,585.00
Summary
Muller cell disfunction is a feature shared by many retinal diseases. This project aims to study the contribution of Muller cell dysfunction to retinal neuronal damage and blood-retinal barrier breakdown in a novel transgenic model we recently generated. Results of this study will also be of interest to scientists and clinicians seeking to understand better and treat diseases of the central nervous system in general.