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
Distribution Of Neurotransmitter Receptors On Identified Cell Populations In The Primate Retina
Funder
National Health and Medical Research Council
Funding Amount
$421,812.00
Summary
Neurons (nerve cells) communicate with each other by releasing chemicals called neurotransmitters at specialized sites called synapses. Each neuron has synaptic receptors, which determine how it will respond to neurotransmitters released by other neurons. The molecular structure and function of these receptors is well understood. Much less is known about the rules that govern which receptor types are expressed by each type of neuron, and how these receptors are distributed to the appropriate syn ....Neurons (nerve cells) communicate with each other by releasing chemicals called neurotransmitters at specialized sites called synapses. Each neuron has synaptic receptors, which determine how it will respond to neurotransmitters released by other neurons. The molecular structure and function of these receptors is well understood. Much less is known about the rules that govern which receptor types are expressed by each type of neuron, and how these receptors are distributed to the appropriate synapses so as to allow the normal function of the nervous system. We will study the distribution of neurotransmitter receptors on identified neurons in the retina. The retina is part of the central nervous system and its highly ordered structure makes it an ideal model nervous system. We will compare the distribution of receptors on neurons that play distinct functional roles in colour and movement detection. These experiments will advance our understanding of the normal functioning of the nervous system.Read moreRead less
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
Neogenin: A Regulator Of Neuronal Differentiation And Migration In The Adult Brain
Funder
National Health and Medical Research Council
Funding Amount
$334,053.00
Summary
Conditions such as Alzheimer�s and Huntington�s diseases, as well as stroke, represent a major burden of disease in Australia. One goal of modern neurobiology is to harness the brain's ability to make new neurons so that we can replace those damaged by disease or injury. We will investigate how an important developmental molecule, Neogenin, promotes the production of new neurons in the adult brain. A second goal is to show that Neogenin can be activated to promote the repair of the damaged brain ....Conditions such as Alzheimer�s and Huntington�s diseases, as well as stroke, represent a major burden of disease in Australia. One goal of modern neurobiology is to harness the brain's ability to make new neurons so that we can replace those damaged by disease or injury. We will investigate how an important developmental molecule, Neogenin, promotes the production of new neurons in the adult brain. A second goal is to show that Neogenin can be activated to promote the repair of the damaged brain.Read moreRead less
The Development Of Glial Cells In The Sympathetic Nervous System
Funder
National Health and Medical Research Council
Funding Amount
$372,025.00
Summary
Nervous system development entails the co-ordinated multiplication of a small number of founder cells to give the millions of cells of the mature nervous system. Each founder generates a many different cell types. Understanding how this is controlled is among the most challenging problems in modern biology. We will show how the development of the two basic cell types (neurons and glia), is controlled in a part of the nervous system that is relatively simple and accessible for manipulation.
Identification Of Genes Involved In Neural Crest Development
Funder
National Health and Medical Research Council
Funding Amount
$482,310.00
Summary
Knowledge of the genes that during embryonic development control the way our bodies form is necessary to understanding how our body systems function in health and disease. However, research on the developmental genetics of vertebrates, including humans, has proceeded very indirectly, mostly by looking for genes similar to those found in other biological systems, most notably the fruit fly. The significance of this research is that it will identify developmental genes directly from the chosen ver ....Knowledge of the genes that during embryonic development control the way our bodies form is necessary to understanding how our body systems function in health and disease. However, research on the developmental genetics of vertebrates, including humans, has proceeded very indirectly, mostly by looking for genes similar to those found in other biological systems, most notably the fruit fly. The significance of this research is that it will identify developmental genes directly from the chosen vertebrate body system as it develops. As a body system we will choose one of the most basic building blocks of the very early nervous system. This building block is an embryonic organ called the Neural Crest that later goes on to form important parts of the nervous system, but in addition it also forms major parts of the head and face, glands in the neck, the large arteries leading out from the heart, and pigment cells (melanocytes) in the skin. It is particularly important to gain insight into development of this organ because the tissues that derive from the neural crest are the most at risk for birth defects and for childhood cancers. Knowledge of neural crest development also tells us about our own evolution, because the neural crest is the only major system found only in vertebrates including humans.Read moreRead less
Understanding how the brain grows and is organised is one of the great challenges of science. This project seeks to identify key regulators of neural progenitors as these are the building blocks from which all brains cells are derived. This knowledge may also identify new avenues through which to manipulate neural progenitor function. This has implications not only for normal brain development but also potential therapies for neural disorders and disease.
Can Human Neural Stem Cells Form Enteric Nerves In Human Hirschsprungs Disease Colon?
Funder
National Health and Medical Research Council
Funding Amount
$598,815.00
Summary
The intestine has its own nervous system which develops from cells that migrate into the intestine during early development. Sometimes this does not work and part of the bowel has no nerves and cannot function. This is treated now by cutting out this bad bowel and joining the sections of good bowel. But it may be possible to grow new nerves in the bad bowel using stem cells. This project aims to test whether this treatment, which would avoid loss of bowel, is possible.
Neural Crest Stem Cell Therapy For Absence Of Intestinal Nerves In Hirschsprungs Disease
Funder
National Health and Medical Research Council
Funding Amount
$504,377.00
Summary
Hirschsprung's disease is acommon birth defect caused by failure of nerve cells to get into the colon. This results in intractable often fatal constipation. Current treatment is surgical removal of the affected colon soon after birth but often problems persist. These nerves might be rebuilt using nerve stem cells, but not all stem cells have this capacity. And is not known if this can be achieved after birth: This project will define which stem cell populations to use and in what age of bowel.