The human brain has many subdivisions (�areas�) that are dedicated to vision, but in many cases their functions remain unclear. This project will study an area located deep in the brain, about which very little is known, and which appears to be affected from early stages in conditions such as Alzheimer�s disease. By understanding the patterns of electrical activity of cells in this region, and their connections with other brain areas, we hope to decipher their contribution to sensory cognition.
In the areas of the brain where visual information is processed, cells respond to the presentation of visual stimuli by changing their pattern of electrical activity. At the first level of analysis, the primary visual cortex (V1), individual cells become active only if line segments or borders of a particular orientation are present in their field of detection, which encompasses a small part of the visual scene. Cells in other visual cortical areas (the extrastriate cortex) perform more complex ....In the areas of the brain where visual information is processed, cells respond to the presentation of visual stimuli by changing their pattern of electrical activity. At the first level of analysis, the primary visual cortex (V1), individual cells become active only if line segments or borders of a particular orientation are present in their field of detection, which encompasses a small part of the visual scene. Cells in other visual cortical areas (the extrastriate cortex) perform more complex detection tasks in comparison with those in V1, which demand integration of information coming from much larger portions of the visual scene. One example of these more complex properties is the phenomenon of long-range contour integration, where our visual system groups individual line segments having similar orientations, so that they are perceived as part of the same contour. This property is reflected in the electrical responses of cells in the dorsomedial visual area (DM). How are properties such as orientation specificity and long-range contour integration created? To begin addressing this question, we will investigate correlations between the physiological properties of identified cells, the spatial distribution of their information collecting regions (dendrites), and the anatomical pathways by which they receive information from other parts of the brain. This is a basic science study aimed at determining the extent to which the anatomical structure of the brain helps define the function of individual cells and brain areas. Its primary benefit will be to increase our understanding of the mechanisms underlying all sensory processing in the brain. The knowledge obtained may also lead to developments in areas of applied research including medicine and cognitive science (for example, understanding how the brain learns to interpret visual information in early life, and how visual processing degrades with ageing).Read moreRead less
High Speed Video To Assess Eye Movements In Vestibular Dysfunction - A Validation Study
Funder
National Health and Medical Research Council
Funding Amount
$133,351.00
Summary
Dizziness affects a third of the population during their lives. Abnormal eye movements are often the best guide as to what has gone wrong in the dizzy person. The problem is that these eye movements can be difficult to see, and hence measure, as a way of diagnosing and then treating the dizziness. Video-oculography holds great promise for helping doctors identify the cause, and in many cases offer simple curative treatment, for dizziness.
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
Dizziness, vertigo, and imbalance affect nearly half the population by the age of 60 and balance-related falls, especially in the elderly, are a serious health concern. Surveys of primary care doctors have shown that dizziness and vertigo are as prevalent as hypertension and angina, and approximately 40% of the population experience dizziness severe enough to seek medical attention. Unfortunately, most symptoms are not relieved by currently available medical treatment. There is, however, a remar ....Dizziness, vertigo, and imbalance affect nearly half the population by the age of 60 and balance-related falls, especially in the elderly, are a serious health concern. Surveys of primary care doctors have shown that dizziness and vertigo are as prevalent as hypertension and angina, and approximately 40% of the population experience dizziness severe enough to seek medical attention. Unfortunately, most symptoms are not relieved by currently available medical treatment. There is, however, a remarkable hidden reserve of 'self-repair' in the balance system that can be triggered under certain conditions. We call this process 'vestibular compensation' and if we can understand those conditions and discover the means by which this reserve affects the nervous system, we may be able harness its power to alleviate the all distressing symptoms of imbalance. Perhaps we may even be able to apply these principles to other critical systems that may need repair. We propose to look at a key region in the central nervous system that is responsible for processing balance signals and may be very important in 'vestibular compensation'. We will try to activate this recovery process under controlled conditions so that we can understand the changes that occur. Specifically we will examine the role of vestibular (balance) neurons in the central nervous system that appear to be modified following trauma of the inner ear balance organs. We will use our new recording techniques to examine these vestibular neurons to see how their intrinsic properties may change and what external or internal factors influences this change. Our aim is to understand what factors promote and what factors inhibit full recovery.Read moreRead less
Our vestibular system provides us with the important sense of balance. When it fails we suffer debiltating bouts of vertigo and dizziness. A great deal is known about how balance signals are sent from the inner ear to our brains, but virtually nothing is known about the important signals the brain sends to the inner ear. In this study we will use a new perparation develped in our laboratory to examine how these essential brain signals control the function of our balance organs.
Opening Windows To The Listening Brain: Developing Objective Measures Of Hearing Acuity In The Human Brain.
Funder
National Health and Medical Research Council
Funding Amount
$319,329.00
Summary
Up to 160,000 Australians are un-employed due to hearing impairment, costing an estimated $12 billion per year. I will undertake systematic research which will result in EEG-based clinical tools designed to measure the reliability and acuity with which brainstem and brain structures are able to encode fine details in sounds. These tools will improve diagnostic and prognostic tests, especially for clinicians and parents of infants diagnosed with auditory neuropathies.
Probing cross modal interactions in the perception of object motion and self-motion. How the brain integrates information from the different senses is not yet understood. This project aims first, to uncover how the brain integrates sound and visual information when perceiving moving objects and second, to probe more complex sensory interactions between sound, vision, and our vestibular senses when perceiving self-motion. This project will expand Australia's knowledge base, strengthen collabora ....Probing cross modal interactions in the perception of object motion and self-motion. How the brain integrates information from the different senses is not yet understood. This project aims first, to uncover how the brain integrates sound and visual information when perceiving moving objects and second, to probe more complex sensory interactions between sound, vision, and our vestibular senses when perceiving self-motion. This project will expand Australia's knowledge base, strengthen collaborative ties between Australia and Japan, and provide unique training opportunities for Australian and Japanese students. Publication of research in top-ranking journals will further promote Australian science abroad. Results will lead to improvements in the design of human-machine interfaces in both industry and entertainment.Read moreRead less
The whisker sensory system: processing information about object features. This is a new direction for research on the whisker sensory system and will put Australia at the forefront in this competitive area. Of particular significance, it will promote cross-fertilisation among three distinct disciplines - neuroscience, animal behaviour and computational neuroscience, with implications for robotics research as well. Should the robotics potential come to fruition, Australia will be in a prime posi ....The whisker sensory system: processing information about object features. This is a new direction for research on the whisker sensory system and will put Australia at the forefront in this competitive area. Of particular significance, it will promote cross-fertilisation among three distinct disciplines - neuroscience, animal behaviour and computational neuroscience, with implications for robotics research as well. Should the robotics potential come to fruition, Australia will be in a prime position to make early inroads into an important technology-based commercial enterprise. The interdisciplinary approach has important ramifications for training Australian PhD students and postdoctoral fellows and for attracting overseas research fellows. Read moreRead less
Mechanisms of learning at the interface between perception and action. Using the latest in brain imaging and simulator technology, this project will advance understanding of how experience shapes the visual centres of our brain. It will also support partnerships with construction, mining and health services by developing real and virtual machine interfaces and tools to enhance the outcome of simulator-based training.