Effect Of Aging And Mitochondrial Dysfunction On The Optic Nerve Response To Pressure-induced Oxidative Stress
Funder
National Health and Medical Research Council
Funding Amount
$415,554.00
Summary
The risk of glaucoma, a potentially blinding disease of the optic nerve, increases exponentially with age, but the cellular mechanisms responsible are not known. We hypothesise that age-related changes in mitochondria, the energy producing part of the cell, render nerve cells prone to damage. This project will determine whether aging and mitochondrial impairment increase nerve damage and whether dietary moodifications that preserve mitochondria during aging, protect the optic nerve from damage
Optimising The Detection Of Early Glaucoma - Targeting Specific Visual Pathways In Combination With Structural Measures.
Funder
National Health and Medical Research Council
Funding Amount
$481,893.00
Summary
This study seeks to determine the optimal methods for detecting early glaucoma - a blinding disease - using new and diverse strategies for selective testing of specific visual pathways, in combination with structural analysis for optic nerve fibre loss. We hope to identify the best combination of available tests to enable earliest identification of glaucomatous damage.
Structure And Function Of The Third Geniculocortical Pathway In Primates.
Funder
National Health and Medical Research Council
Funding Amount
$296,777.00
Summary
Our understanding of the human visual system has been based on the idea that there are two main nerve pathways from the eye to the brain. One, called the parvocellular pathway, is for colour and detail vision, and the other, called the magnocellular pathway, is for movement perception. Damage to either pathway by disease such as glaucoma, or a lesion such as stroke, will cause specific changes in visual perception and these changes can be used to diagnose the nature of the disease or lesion. We ....Our understanding of the human visual system has been based on the idea that there are two main nerve pathways from the eye to the brain. One, called the parvocellular pathway, is for colour and detail vision, and the other, called the magnocellular pathway, is for movement perception. Damage to either pathway by disease such as glaucoma, or a lesion such as stroke, will cause specific changes in visual perception and these changes can be used to diagnose the nature of the disease or lesion. We will study a recently recognised third subdivision of the visual pathway, called the koniocellular pathway. The properties of koniocellular cells have not previously been studied in anthropoid primates, and their importance for human vision is not well understood. We will study the way that koniocellular cells respond to moving and patterned stimuli, and their connections with the cerebral cortex, in order to determine whether this pathway could contribute to aspects of normal and abnormal visual perception. We will follow up our preliminary evidence that koniocellular cells respond to visual stimuli of the type used to diagnose the early stages of eye diseases such as glaucoma. The results will give us a better understanding of the way that the nervous system processes visual information, and will clarify the basis of disturbances to normal visual function.Read moreRead less
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
Origin And Specificity Of Neuronal Signals For Colour Vision In Primates.
Funder
National Health and Medical Research Council
Funding Amount
$490,500.00
Summary
How do we see colours? What do colour blind people see? Although colour is one of the most important attributes of objects in the visual world, the way that colour is processed in the brain is poorly understood. The aim of this project is to study the way that nerve cells in the eye (the retina) and the visual part of the brain are specialised to transmit signals for colour perception. The visual system of humans and other primates includes nerve cells which are selective for a limited range of ....How do we see colours? What do colour blind people see? Although colour is one of the most important attributes of objects in the visual world, the way that colour is processed in the brain is poorly understood. The aim of this project is to study the way that nerve cells in the eye (the retina) and the visual part of the brain are specialised to transmit signals for colour perception. The visual system of humans and other primates includes nerve cells which are selective for a limited range of wavelengths reflected by objects in the visual world. We will study how this selectivity is generated, by examining how the colour receptors are connected within the retina to the cells which transmit nerve impulses to the brain. Between 5 and 7 percent of male humans have colour vision defects. Many objects which appear clearly different to colour-normal observers cannot be discriminated by colour-defective observers, and entry to professions such as the police and airline industry is restricted for individuals with colour vision defects. We will study the basis of reduced colour perception ability in red-green colour blindness. This will be done by measuring the responses of nerve cells in a species of primate (marmoset) in which many animals have colour vision receptors resembling those of humans with colour vision defects. We will measure the reliability with which individual neurones can transmit signals for colour vision when they receive input from such abnormal receptors. It is known that nerve cells transmit their message within the brain by means of brief electrical impulses called action potentials. In addition to studying the basis of human colour discrimination, the project also addresses one of the fundamental questions of sensory processing, by studying the reliability of the coded message carried by action potentials within the central nervous system.Read moreRead less
Non-standard Receptive Fields In The Primate Visual System
Funder
National Health and Medical Research Council
Funding Amount
$392,983.00
Summary
We recently discovered that an evolutionary ancient brain pathway transmits visual signals for blue-yellow colour vision. We now plan to discover whether this pathway could also contribute to form and movement perception, and to visual functions (called blindsight) that survive damage to the main visual area of the brain. This project will contribute to understanding the effects of damage to visual pathways following stroke or brain injury, as well as to understanding normal visual function.
Synaptic Connectivity Of Colour Pathways In Primate Retina
Funder
National Health and Medical Research Council
Funding Amount
$367,500.00
Summary
The first step in the visual process occurs when light enters the eye and activates specialised nerve cells called photoreceptors. The photoreceptors for daytime vision (called cones for their cone-like shape) comprise three types, which are sensitive to the long- (red), medium- (green) or short-wavelength (blue) regions of the visible spectrum. Although the properties of the cones are well known, the way in which they are functionally connected to nerve pathways for vision is not clearly unders ....The first step in the visual process occurs when light enters the eye and activates specialised nerve cells called photoreceptors. The photoreceptors for daytime vision (called cones for their cone-like shape) comprise three types, which are sensitive to the long- (red), medium- (green) or short-wavelength (blue) regions of the visible spectrum. Although the properties of the cones are well known, the way in which they are functionally connected to nerve pathways for vision is not clearly understood. Clinical research has shown that reduced sensitivity to blue light is a feature of the early stages of certain visual diseases (for example, glaucoma), so it is important to know how the short-wavelength (blue) cones contribute to visual functions such as form, motion and colour perception. Such knowledge can help to design better tests for diagnosis of visual disorders, and will improve our understanding of the normal function of the visual system in the human brain. In this project the connections of neurones in the primate retina (the nerve cells which line the back of the eye) will be analysed. The blue cones and other nerve cells will be identified using contemporary anatomical methods (double- and triple-label immunocytochemistry) combined with a new method for high-resolution light microscopy, called deconvolution microscopy. Immunocytochemistry is a method borrowed from the field of immunology, where specific antibodies are raised which bind selectively to label specific populations of neurones. Deconvolution microscopy allows rapid and simultaneous visualisation of multiple labelled cell classes, at a resolution close to the limit of the light microscope. Together, these techniques allow the wiring diagram of the blue cones within the retina to be analysed to a higher level of accuracy than previously achieved. The results will improve our understanding of the role of blue-cone circuits in normal vision and visual disorders.Read moreRead less