Electroretinogram Recordings Of Human Scotopic Dark Adaptation Following Intense Bleaching Exposures
Funder
National Health and Medical Research Council
Funding Amount
$272,250.00
Summary
After a human subject has been exposed to intense illumination, it can take many minutes for the eye to regain full sensitivity, as one experiences (for example) when entering a dark cave after being out on a bright sunny beach. This project will investigate the processes that occur in the cells of retina lining the back of the eye, that prevent the instantaneous recovery of vision following intense illumination. Electrical recordings will be made from the eyes of normal individuals, using new t ....After a human subject has been exposed to intense illumination, it can take many minutes for the eye to regain full sensitivity, as one experiences (for example) when entering a dark cave after being out on a bright sunny beach. This project will investigate the processes that occur in the cells of retina lining the back of the eye, that prevent the instantaneous recovery of vision following intense illumination. Electrical recordings will be made from the eyes of normal individuals, using new techniques that allow the activity of different types of nerve cell in the retina to be monitored. The study will determine how it is that events in the light-detector cells of the eye (the rod and cone photoreceptors) influence the activity of subsequent nerve cells in the visual system, and how these events contribute to the poor vision that one experiences following bright lights.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.
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
The Structural Basis Of Direction Selectivity In The Retina
Funder
National Health and Medical Research Council
Funding Amount
$401,705.00
Summary
The retina is part of the central nervous system and there are almost one hundred types of retinal neurons which process visual information before it is passed up the optic nerve to the brain. This project examines how some of these neurons are wired together to form a simple neuronal circuit that detects the direction of a moving object. The elucidation of the cellular mechanisms of direction selectivity will provide an important paradigm of complex processing by simple neuronal circuits, with ....The retina is part of the central nervous system and there are almost one hundred types of retinal neurons which process visual information before it is passed up the optic nerve to the brain. This project examines how some of these neurons are wired together to form a simple neuronal circuit that detects the direction of a moving object. The elucidation of the cellular mechanisms of direction selectivity will provide an important paradigm of complex processing by simple neuronal circuits, with direct relevance to information processing in other parts of the central nervous system. In particular, the project may provide strong evidence for two neuronal strategies that may be of general significance. First, information may be processed at a very local level, which would greatly increase the computational power of a single neuron. Second, neurons may make selective contact with only some processes of an input neuron, which would require novel mechanisms for producing the necessary specificity.Read moreRead less
I am a neuroscientist interested in injury to the nervous system with emphasis on promoting functional recovery and clinical translation. Injury models are neurotrauma, the long-term effects of maternal drug administration on offspring and diabetic retino
The Significance Of Glial Dysfunction In Retinopathy Of Prematurity
Funder
National Health and Medical Research Council
Funding Amount
$311,567.00
Summary
Abnormalities in cells at the back of the eye called photoreceptors are associated with at least 50% of all cases of blindness in this country.This project will determine whether substances released from dying photoreceptors cause the death of neighbouring cells. In addition we will examine whether treatments that block the actions of these released substances can prevent the death of photoreceptors, thereby providing a novel therapeutic agent for the treatment of devastating eye diseases.
TRAFFICKING OF METABOLITES BETWEEN M LLER CELLS AND NEURONS IN DIABETIC RETINOPATHY.
Funder
National Health and Medical Research Council
Funding Amount
$211,320.00
Summary
Diabetes is the leading cause of blindness in the working population. In some diabetics, blood vessels within the retina proliferate, haemorrhage or cause retinal detachment. The underlying changes within the retina that lead to the proliferation of blood vessels are not well understood. One of the factors that leads to changes in retinal blood vessels is an incease in growth factors from cells in the retina called Muller cells. Muller cells are vital for the normal function of the retina, and a ....Diabetes is the leading cause of blindness in the working population. In some diabetics, blood vessels within the retina proliferate, haemorrhage or cause retinal detachment. The underlying changes within the retina that lead to the proliferation of blood vessels are not well understood. One of the factors that leads to changes in retinal blood vessels is an incease in growth factors from cells in the retina called Muller cells. Muller cells are vital for the normal function of the retina, and are known to be abnromal late in diabetes. They may also be dysfunctional early in diabetes and could play a significant role in the early chnages seen in diabetes. Therefore a good understanding of how Muller cells change and the time at which they change is vitally important to gain a better undetrstanding of the defects that are associated with diabetes. Furthermore, an understanding of the basic underlying cellular changes that occur in diabetes will aid the development of more specific therapeutic agents in the future.Read moreRead less
The Role Of Purines In Photoreceptor Death During Retinal Degeneration.
Funder
National Health and Medical Research Council
Funding Amount
$458,729.00
Summary
Abnormalities in cells at the back of the eye called photoreceptors are associated with at least 50% of all cases of blindness in this country.This project will determine whether substances released from dying photoreceptors cause the death of neighbouring cells. In addition we will examine whether treatments that block the actions of these released substances can prevent the death of photoreceptors, thereby providing a novel therapeutic agent for the treatment of devastating eye diseases.
Using Contextual Effects To Test Theories Of Coding In Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$200,500.00
Summary
The visual cortex is the main structure in the brain that processes the visual scene. Cells in the cortex respond selectively to features of the scene such as the orientation of objects, the direction they move and their brightness relative to the background. Cortical cells are arranged in a topographic map of visual space, so that nearby cells respond to light from nearby parts of the image. Recent advances have shown that cells talk to each other so a stimulus in one part of the visual field c ....The visual cortex is the main structure in the brain that processes the visual scene. Cells in the cortex respond selectively to features of the scene such as the orientation of objects, the direction they move and their brightness relative to the background. Cortical cells are arranged in a topographic map of visual space, so that nearby cells respond to light from nearby parts of the image. Recent advances have shown that cells talk to each other so a stimulus in one part of the visual field can influence the responses of cells looking at other regions. This communication between cells is important in guiding the brain to focus on areas of the visual scene that are most important, a process known as attention. An example would be that a mouse moving through the periphery of someone's vision would attract their attention away from objects elsewhere in the scene. This project is designed to study the way that cells in the visual cortex cooperate to guide attention. Attention is important because it reduces the need to process all the detail in the visual scene with the same level of accuracy, leaving more resources free to process what is important. Attention deficits are a problem for people with dyslexia, so understanding the physiological basis of attention is an important goal. As well as attention, the visual system has a range of other mechanisms to select important information from the visual scene. For example, visual adaptation tends to improve the ability to code changes in the visual scene at the expense of reducing the sensitivity of the system overall. This project will investigate the relationship between attentional and adaptive mechanisms in the visual cortex. We expect to establish the precise physiological mechanisms that drive adaptive and attentional mechanisms in the mammalian brain.Read moreRead less
Experimental Validation Of A Clinical Indicator Of Utricular Function.
Funder
National Health and Medical Research Council
Funding Amount
$198,689.00
Summary
The vestibular system is responsible for our sense of balance, it is located in the inner ear and is responsible for maintaining posture and helping an organism to make appropriate eye movements when the head moves. Damage to the vestibular system by disease or accident is extremely debilitating for a patient. A chief goal of our research program is to develop simple tests of the vestibular system that can be used in the clinic to diagnose vestibular disorders. Most present clinical tests only t ....The vestibular system is responsible for our sense of balance, it is located in the inner ear and is responsible for maintaining posture and helping an organism to make appropriate eye movements when the head moves. Damage to the vestibular system by disease or accident is extremely debilitating for a patient. A chief goal of our research program is to develop simple tests of the vestibular system that can be used in the clinic to diagnose vestibular disorders. Most present clinical tests only test the part of the vestibular system that responds to angular rotations (the semicircular canals). There are few good tests that can reliably diagnose problems concerned with sensed position (the otoliths). Recent evidence from human studies has shown that by delivering small electrical currents (galvanic stimulation) via electrodes located on the surface of the skin behind the ears, a characteristic pattern of eye movement occurs. Our hypothesis is that the distinctive pattern of eye movement produced is a result of otolith stimulation. The aim of this project is to determine exactly how these small currents produce the eye movements and if these eye movements are in fact mediated by the otoliths. To determine the physiology that underlies these types of responses we are unable to conduct these experiments in humans. Our present program will therefore use both behavioural and physiological experiments on guinea pigs to test our hypotheses about galvanic stimulation and otolith function. The significance of this work lies in that it will lead to a new way of evaluating the function of the gravity sensing part of the human vestibular system which appear to be uniquely important for patients with balance problems.Read moreRead less