A Study Of The Role Of Voltage-gated Potassium Channels In The Process Of Phototransduction, In The Setting Of Photoreceptor Sensitivity Levels And Response Times, And In The Progression Of A Distinctive Form Of Inherited Retinal Dystrophy
Funder
National Health and Medical Research Council
Funding Amount
$360,371.00
Summary
Inherited retinal disease is a major cause of blindness but the genetic basis is extremely heterogeneous. One such disorder, cone dystrophy with supernormal rod ERG, arises from mutations in KCNV2 that encodes a potassium voltage-gated channel protein. The objective of the project is to use animal models of the disease to determine the role of this channel protein in normal visual function and to assess the impact of loss of function on retinal development and function.
Functional Connectivity Between Visual Cortical Areas In The Non-human Primate
Funder
National Health and Medical Research Council
Funding Amount
$387,585.00
Summary
Visual information going from the eyes to the brain is processed in different parts of the brain to extract useful information. However, to be able to select what is important from among the vast number of objects in the scene, top-down signals from higher areas need to act on incoming signals in earlier areas. This project aims to identify what sort of neural pathways are involved in this and how it is done at the cellular level.
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 Role Of Ten-m3 In Patterning Ipsilateral Retinal Projections
Funder
National Health and Medical Research Council
Funding Amount
$453,042.00
Summary
The normal functioning of the brain depends on connections of billions of nerve cells or neurons. We have found that a protein called Ten_m3 plays a very important role in specifying the way that neurons from the eye connect to the brain. The role of this protein is so important that mice which lack the protein behave as if they are blind. The aim of this project is to understand how this protein controls the development of the visual system.
Network Properties Of Colour Pathways In Primates.
Funder
National Health and Medical Research Council
Funding Amount
$594,891.00
Summary
This project concerns the way in which the eye and brain work together, to enable perception of the colour, form, and movements of objects in the visual world. It is thought that these different attributes of the visual environment are signalled by several parallel nerve pathways in the visual system, but the nature of the neuronal code carried by these pathways remains poorly understood. The aim of our project is to address this basic question, in experimental studies of the intact primate visu ....This project concerns the way in which the eye and brain work together, to enable perception of the colour, form, and movements of objects in the visual world. It is thought that these different attributes of the visual environment are signalled by several parallel nerve pathways in the visual system, but the nature of the neuronal code carried by these pathways remains poorly understood. The aim of our project is to address this basic question, in experimental studies of the intact primate visual system. We plan two sets of experiments. Firstly, we will test the hypothesis that signals for both high-acuity form vision and red-green colour vision can be carried along a single neuronal pathway. We will determine whether response timing in nerve pathways provides a clue by which colour and brightness variation in the environment can be discriminated. Secondly, we will study the segregation of colour and acuity-related signals in the brain, using the method of functional optical imaging. This method, which allows nerve activity to be monitored at high resolution, over relatively large areas of the brain surface (cortex), will allow us test the hypothesis that colour signals are segregated to distinct regions of the visual cortex. These experiments address basic questions, but have application to human vision and visual dysfunction. Good acuity is essential for everyday tasks such as reading, and specific defects in colour vision are used for early detection of neurological dysfunction in diseases such as glaucoma and multiple sclerosis. Understanding the properties of neurons which underlie visual perception can thus help us to understand normal visual performance, and to develop better methods for detection and treatments for such disorders.Read moreRead less
Rationale For Non-invasive Treatment Of Retinopathy Of Prematurity: Dark Rearing As A Means Of Mimicking Physiological Vascularisation
Funder
National Health and Medical Research Council
Funding Amount
$413,900.00
Summary
We aim to develop a new, non-invasive and cost-effective treatment for the disease Retinopathy of Prematurity, the leading cause of childhood blindness across the globe. We intend to test our hypothesis that raising neonates in conditions of total darkness and high oxygen will closely mimic conditions for inducing normal retinal vascular development, and thus prevent the initiating event of the disease. Ultimately, the project intends to lay the groundwork for a translation to the human conditio ....We aim to develop a new, non-invasive and cost-effective treatment for the disease Retinopathy of Prematurity, the leading cause of childhood blindness across the globe. We intend to test our hypothesis that raising neonates in conditions of total darkness and high oxygen will closely mimic conditions for inducing normal retinal vascular development, and thus prevent the initiating event of the disease. Ultimately, the project intends to lay the groundwork for a translation to the human condition.Read moreRead less