Centre-surround interactions in ageing human vision. Australia has a rapidly ageing population. This project will study how ageing affects the visual perception of objects presented on non-uniform backgrounds. Our ability to discriminate objects from their backgrounds is key to most natural visual tasks. The visual processes involved are known as centre-surround interactions, and are considered fundamental building blocks to human perception. This project will significantly advance our knowledge ....Centre-surround interactions in ageing human vision. Australia has a rapidly ageing population. This project will study how ageing affects the visual perception of objects presented on non-uniform backgrounds. Our ability to discriminate objects from their backgrounds is key to most natural visual tasks. The visual processes involved are known as centre-surround interactions, and are considered fundamental building blocks to human perception. This project will significantly advance our knowledge of which spatial visual mechanisms are altered due to age, supplying key information for understanding and improving visual environments for the elderly, as well as increasing knowledge of the brain mechanisms susceptible to the ageing process.Read moreRead less
Neural Mechanisms That Limit The Visual Sensitivity Of Primates
Funder
National Health and Medical Research Council
Funding Amount
$379,400.00
Summary
This project concerns the way nerve cells in the brain enable the detection and perception of objects in the visual world. It is thought that nerve cells early in the visual pathway signal the presence or absence of light in a small part of the visual field, 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 will conduct two sets of exper ....This project concerns the way nerve cells in the brain enable the detection and perception of objects in the visual world. It is thought that nerve cells early in the visual pathway signal the presence or absence of light in a small part of the visual field, 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 will conduct two sets of experiments. Firstly, we will test the hypothesis that nerve cells in the early visual system are sensitive to only a small part of the visual field. We will determine whether the signals of pre-cortical nerve cells are dependant on spatial context. Secondly we wll study the signals of several nerve cells simultaneously using multiple electrodes. We will determine if the signals of many nerve cells are required to detect small visual stimuli like those used in perimetry. 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 defects in visual sensitivity are used for early detection of neurological dysfunction in diseases such as glaucoma and macular degeneration. Understanding the properties of neurons which underlie visual perception can thus help us to understand normal visual performance, and how this changes in partial sight. This can help develop better methods for detection and treatments for such disorders.Read moreRead less
One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. In this project, we will address the organization of a poorly known group of visual areas, which is located deep in a part of the brain called the in ....One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. In this project, we will address the organization of a poorly known group of visual areas, which is located deep in a part of the brain called the interhemispheric fissure (the medial complex of visual areas). Preliminary evidence suggests that these areas may provide anatomical shortcuts linking vision, behavioural reactions, and emotion. Suppose, for example, that you are sitting outside reading. Although deep in concentration, you are still able to detect the sudden movement of an approaching object in your peripheral field of vision. In many cases you can react (e.g., by ducking , or raising your arms to protect the face) long before you register what the object actually is. An adrenaline rush often accompanies these quick motor reactions, implying a parallel activation of the autonomic nervous system. While the mechanism by which the brain promotes these quick reactions remains poorly understood, we believe that the medial complex of visual areas holds the key. The aim of this study is to map the anatomical framework underlying our ability to react to sudden stimuli in our peripheral visual field. Such work is fundamental for understanding the functional organization of the brain. It also has the potential to lay the groundwork for developments in areas of applied research, including medicine (e.g. the design of better rehabilitation strategies for people with brain damage) and the cognitive sciences (e.g. a better understanding of the factors that limit human responses to visual stimuli).Read moreRead less
Neural plasticity in older adult human vision. This project aims to expand our understanding of age related changes in brain function, specifically plasticity. The project will increase knowledge of the role of an inhibitory neurotransmitter GABA in visual plasticity. Expected outcomes include new knowledge regarding the regulation of brain function in adulthood, enabling future research and planning for societal benefit to older Australia.
New, Efficient Tests That Map Both Central and Peripheral Vision. This project seeks to develop a new, combined approach for quantifying both central and peripheral vision with a single test. Current methods for testing far peripheral vision are not efficient and not fully automated. Yet peripheral vision is important for tasks involving navigation and hazard avoidance such as driving. The project intends to invent and test new approaches to sampling and measuring the spatial extent of vision. T ....New, Efficient Tests That Map Both Central and Peripheral Vision. This project seeks to develop a new, combined approach for quantifying both central and peripheral vision with a single test. Current methods for testing far peripheral vision are not efficient and not fully automated. Yet peripheral vision is important for tasks involving navigation and hazard avoidance such as driving. The project intends to invent and test new approaches to sampling and measuring the spatial extent of vision. The anticipated algorithms will be more accurate and efficient than current tests, will be suitable for older adults, and will enable ready assessment of vision for occupational tasks.Read moreRead less
Wiring the retina for human vision - a single-cell behavioural approach. This project aims to combine optical and behavioural methods to explore how colour information is channelled from individual cone photoreceptors through the living human retina, to the brain. By non-invasively stimulating either a single cell or specific arrangements of cells, the project aims to contribute fundamental knowledge about how the retina is wired to inform our exquisite sense of colour and spatial vision. This u ....Wiring the retina for human vision - a single-cell behavioural approach. This project aims to combine optical and behavioural methods to explore how colour information is channelled from individual cone photoreceptors through the living human retina, to the brain. By non-invasively stimulating either a single cell or specific arrangements of cells, the project aims to contribute fundamental knowledge about how the retina is wired to inform our exquisite sense of colour and spatial vision. This understanding has consequences across a range of disciplines, including artificial vision systems such as driverless cars, retinal disease, and the processing of information through neuronal connections in general.Read moreRead less
The effect of cochlear implants on cognitive decline in ageing Australians. This project aims to investigate the impact of cochlear implants on cognitive function in elderly people with deafness. Deafness has been found to be independently associated with a 30–40 per cent accelerated rate of cognitive decline in elderly adults. There is currently no effective treatment for cognitive decline. The intended outcomes of this observational study will help us to understand the biological process of co ....The effect of cochlear implants on cognitive decline in ageing Australians. This project aims to investigate the impact of cochlear implants on cognitive function in elderly people with deafness. Deafness has been found to be independently associated with a 30–40 per cent accelerated rate of cognitive decline in elderly adults. There is currently no effective treatment for cognitive decline. The intended outcomes of this observational study will help us to understand the biological process of cognitive decline, whether hearing loss is causal, and whether the process can be altered. These findings should be applicable to all individuals with hearing loss. If cochlear implants delay cognitive decline, this would significantly affect policy, quality of life for the elderly, and the cost to society.Read moreRead less
The effect of multisensory and sensory-motor training on auditory accommodation. Learning to use a hearing aid or cochlear implant requires the brain to make adaptive changes to the new type of sensory information provided to the ears. This project examines what drives this accommodation and how we may accelerate the process and maximise its benefits by training so that listeners are able to make better use of these devices.
Identifying the basis for perceptual stability and perceptual omission during saccadic eye movements. The ability to explore the world via eye movements is an important feature of visual capabilities. This project will establish how the brain maintains the perception of a stable and stationary world despite the several eye movements made each second. This knowledge will fill a conspicuous gap in the understanding of the human visual system.