The Rane And Spain Routes In The Brain: Functional Studies And Remediation In Dyslexia Subtypes.
Funder
National Health and Medical Research Council
Funding Amount
$374,426.00
Summary
According to a recent DEST report a disturbingly high number of Australian school children are failing to meet a minimum acceptable standard in literacy . Failure to reach these standards is associated with poorer outcomes in mental health and socioeconomic status, greater representation among the prison population and with failure to achieve to true ability. Further, failure to correct these problems may well result in transmission of the problems associated with failed literacy into the next g ....According to a recent DEST report a disturbingly high number of Australian school children are failing to meet a minimum acceptable standard in literacy . Failure to reach these standards is associated with poorer outcomes in mental health and socioeconomic status, greater representation among the prison population and with failure to achieve to true ability. Further, failure to correct these problems may well result in transmission of the problems associated with failed literacy into the next generation. Despite the obvious immense social and personal ramifications and cost, literacy instruction for adults continues to lack a theoretical and research based approach . It is plain that improving population literacy would have significant benefits and it is also plain that early detection, intervention and remediation is desirable. This project brings to bear on these important aims current expertise in the nature of reading, how children learn to read and why some have so much difficulty in doing so, and techniques for determining the neural substrates of the mechanisms involved in reading and learning to read. We will subdivide child readers on the basis of their ability to read words using the letter to sound route or dictionary look-up route. We will use magnetic resonance imaging and spectroscopy to examine which parts of the brain are disrupted and-or disconnected when ability to read in either of these two routes is poor. We will then remediate these poor readers using targetted remediation therapy and re-image them to see whether remediation has altered the way the brain reads.Read moreRead less
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.
Auditory Processing Deficits In Specific Language Impairment And Specific Reading Disability:Their Effects And Treatment
Funder
National Health and Medical Research Council
Funding Amount
$314,250.00
Summary
One possible cause of specific language impairment (SLI) and specific reading disability (SRD; commonly known as dyslexia) is an inability to discriminate between sounds. Such an impairment could affect the ability to discriminate between simple speech sounds (phonemes) which are the basic building blocks for developing spoken language and reading skills. How many children with SLI or SRD have poor sound discrimination? What pattern of spoken language and reading impairments do these children ha ....One possible cause of specific language impairment (SLI) and specific reading disability (SRD; commonly known as dyslexia) is an inability to discriminate between sounds. Such an impairment could affect the ability to discriminate between simple speech sounds (phonemes) which are the basic building blocks for developing spoken language and reading skills. How many children with SLI or SRD have poor sound discrimination? What pattern of spoken language and reading impairments do these children have as a result of this impairment? Can poor sound discrimination be fixed? If it can, does it improve spoken language and reading impairments? And if it does, does it have an immediate effect or does it take some time to make a difference? These are some of the questions that will be addressed by this research. The answers will help us develop a training program that focuses specifically on improving the sound discrimination abilities of children who really need it. This will be a more efficient and inexpensive (if not free) than the Fast ForWord program that trains multiple non-verbal and verbal processing abilities regardless of whether a child has an impairment in all (or any) of these abilities and is therefore time consuming (approximately 80 hours) and expensive (approximately $AUD2000). The data will also help up better identify the spoken and written language profiles that characterise children who have sound discrimination deficits so we can better predict whether they would benefit from training programs such as Fast ForWord. And the data will tell use whether impaired sound discrimination can be used to predict whether infants might be at risk for later spoken language and reading problems.Read moreRead less
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
Interactions Between Afferent Channels In Vision: Basic Neurophysiology And Implications For The Pathology Of Dyslexia
Funder
National Health and Medical Research Council
Funding Amount
$423,662.00
Summary
We intend to study the interactions between different information channels in the primate visual system. The pathways from the eyes to the brain consist of different types of nerve fibres carrying distinct sorts of information. These channels have been believed to remain separate as they transmit the information through various levels of the brain. Finally, in the neocortex, it has been suggested that the visual information goes along two major streams, one dorsally to the parietal cortex and th ....We intend to study the interactions between different information channels in the primate visual system. The pathways from the eyes to the brain consist of different types of nerve fibres carrying distinct sorts of information. These channels have been believed to remain separate as they transmit the information through various levels of the brain. Finally, in the neocortex, it has been suggested that the visual information goes along two major streams, one dorsally to the parietal cortex and the other ventrally to the temporal cortex. Based upon recent studies, we question this strict segregation of the pathways and propose to study how interactions occur between the two streams and whether the two channels do come together at early levels of the visual pathway. We will also test our idea whether, of the dorsal and ventral streams, one stream might actually gate the other and decide what goes through the other stream. In fact, from our own recent studies, we have reason to believe that the way our attentional system might operate to select salient aspects of the visual scene may be through the dorsal stream selecting what goes into the ventral stream, which seems to be responsible for identifying objects. In the proposed project we will test this idea rigorously. From various lines of evidence, we also argue that the neural mechanisms that underlie this attentional spotlight is exploited by human children when they learn to read. It follows that any defect in the dorsal pathway or in the fibres and cells that feed into this will cause difficulties in reading. We believe this to be the underlying problem in dyslexic children. The project will undertake a number of experiments to test this idea.Read moreRead less
Molecular Genetics Of Dyslexia: A Component Processes Approach
Funder
National Health and Medical Research Council
Funding Amount
$348,960.00
Summary
With the advent of the human genome project, Australian researchers into serious childhood reading disorders are now in a position to make breakthroughs in understanding the complex linkages between genes and dyslexia. It is widely acknowledged that previous studies on the genetics of dyslexia have been limited by their failure to distinguish the different component processes in reading and the different patterns of dyslexia that they produce, and by being unable to look widely across the human ....With the advent of the human genome project, Australian researchers into serious childhood reading disorders are now in a position to make breakthroughs in understanding the complex linkages between genes and dyslexia. It is widely acknowledged that previous studies on the genetics of dyslexia have been limited by their failure to distinguish the different component processes in reading and the different patterns of dyslexia that they produce, and by being unable to look widely across the human genome. This new research addresses these two problems. Firstly, the researchers have developed a computational model of reading that identifies around a dozen basic mental processes which are recruited during skilled reading. This model provides the extremely precise phenotypes required for genetic research. Secondly, the researchers will take advantage of both very high density scans within known regions of interest on chromosomes 2,6, and 15, as well as a genome-wide scan of 400 markers small elements of DNA whose position within the genome is known, thus allowing researchers to narrow-down the location of new genes for reading. The research thus promises not only to refine our understanding of the basis for three previous genetic markers of dyslexia, but also to potentially uncover new genes related to specific elements of reading across the genome. The project pools the resources of the Macquarie Centre for Cognitive Science, the Australian Genome Research Facility, and The Garvan Institute and the researchers hope that the work will lead eventually to identifying the genes for dyslexia and to improved diagnosis and treatment of reading disorders in Australia.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
The Functional Organisation And Signals Of Motion Sensitive Neurons In The Middle-temporal Area Of Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$405,337.00
Summary
Some nerve cells in the cerebral cortex are very sensitive to visual motion. These neurons direct eye movements and provide motion perception, but the "neuronal code" they carry is poorly understood. We will address this basic question in experimental studies of the primate visual system. This project will help us understand visual performance; poor motion vision is an early indicator of many neurological disorders and this knowledge can help develop methods for their detection and diagnosis.
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