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
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
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.
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.
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.
The Role Of Gliosis In Advanced Retinal Degeneration
Funder
National Health and Medical Research Council
Funding Amount
$457,785.00
Summary
The development of treatments that restore vision assumes that the output neurons of the retina remain intact. Yet, there is now considerable evidence that the neurons that signal from the retina to the brain are altered in those that have degenerative diseases of the retina. Here, we will examine the cause of these cellular changes in an animal model and seek to prevent the loss of output neurons. This information is crucial for the development of treatments that seeks to restore vision.
Novel Functional Imaging For Age-related Macular Degeneration
Funder
National Health and Medical Research Council
Funding Amount
$564,848.00
Summary
Age-related macular degeneration (AMD) is an eye condition which affects the central retina (the macula) resulting in a loss of central vision. The lack of appropriate clinical tests to monitor the progression of AMD at the early stages of disease hampers the discovery of novel interventions aimed at preventing the development of advanced vision-threatening AMD. In this project, we will investigate the use of a quick and non-invasive imaging technique for monitoring AMD progression.
How Does Glucose Protect The Retina And Optic Nerve Against Ischaemia?
Funder
National Health and Medical Research Council
Funding Amount
$418,171.00
Summary
Raised blood sugar levels are generally considered to be bad for nerve cells, especially those in the eye. But we have made a groundbreaking discovery finding that in the short-term, sugar can rescue nerve cells in the eye from death caused by lack of blood flow. In this project we will investigate how this remarkable effect is achieved.
Novel Mechanisms Of Early Age Related Macular Degeneration
Funder
National Health and Medical Research Council
Funding Amount
$933,953.00
Summary
Age Related Macular degeneration (AMD) is a leading cause of blindness in Australia. In this project we will examine a novel mechanism by which the cells at the back of the eye, called retinal pigment eptihelial cells contribute to vision loss early in the disease. In addition we will examine the potential for two currently used drugs as well as a novel laser treatment in slowing the progression of disease.
The Role Of Estrogen Signalling In The Development And Progress Of Neovascularisation In Macular Degeneration
Funder
National Health and Medical Research Council
Funding Amount
$318,768.00
Summary
Age-related macular degeneration is a common eye disease. In the advanced stages of the disease, abnormal and leaky blood vessels form, causing permanent and severe vision loss. A novel treatment is the application of the sex hormone, estrogen, which could halt abnormal blood vessel growth in the eye. This project aims to confirm the protective effects of estrogen on eye health and whether mutations in estrogen-related genes alter the risk of vision loss due to abnormal blood vessel growth.