Information Encoding By Temporal Structure Of Afferent Spike Trains
Funder
National Health and Medical Research Council
Funding Amount
$231,175.00
Summary
Our ability to sense, discriminate and interpret touch stimuli underpins some of the most crucial functions of the human hand that relate to object exploration and manipulation. The fundamental mechanism of how nerve impulses generated by tactile receptors are interpreted by the nervous system is not understood. Only by discovering the underlying neural encoding mechanisms can we appreciate the functional impairments in patients and learn to identify them before they become widespread and irreve ....Our ability to sense, discriminate and interpret touch stimuli underpins some of the most crucial functions of the human hand that relate to object exploration and manipulation. The fundamental mechanism of how nerve impulses generated by tactile receptors are interpreted by the nervous system is not understood. Only by discovering the underlying neural encoding mechanisms can we appreciate the functional impairments in patients and learn to identify them before they become widespread and irreversible.Read moreRead less
InTOUCH: Tactile Assessment In Children With Cerebral Palsy
Funder
National Health and Medical Research Council
Funding Amount
$176,571.00
Summary
Recent research finds that over 70% of children with unilateral cerebral palsy have impairments in touch function that affect how well they can use their hands. Until now, the severity and extent of this deficit has been unknown, and so children with cerebral palsy have not been receiving touch assessments. This project aims to increase awareness of touch impairments and achieve integration of touch assessment into routine examaination.
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
The broad aim of this project is to understand how the eye receives visual signals and sends them to the brain. Our experimental goal is to study the structure of neural connections in a poorly understood division of the visual system, called the koniocellular pathway. The cells of the koniocellular pathway make up close to 10 percent of all projections from the eye to the brain, but their functions are almost completely unknown. The fovea is a specialised region of the retina (the nerve cells w ....The broad aim of this project is to understand how the eye receives visual signals and sends them to the brain. Our experimental goal is to study the structure of neural connections in a poorly understood division of the visual system, called the koniocellular pathway. The cells of the koniocellular pathway make up close to 10 percent of all projections from the eye to the brain, but their functions are almost completely unknown. The fovea is a specialised region of the retina (the nerve cells which line the back of the eye). It is characterised by a very high density of cone photoreceptors, and is essential for high-acuity vision. This makes the fovea the most important part of the primate retina, but the high density of nerve cells there is thought to be the reason why the fovea is especially vulnerable to disease and age-related degeneration. Our aim is to analyse, using high-resolution microscopic techniques, the connections of koniocellular-pathway cells within the retina. We specifically aim to discover whether the koniocellular pathway contributes to foveal vision. Recent work from our and other laboratories has shown that many koniocellular-pathway cells receive functional connections from short-wavelength sensitive (blue) cone photoreceptors. Thus, our study will provide new insights into the connectivity of blue-cone pathways in the fovea. Although these experiments address basic scientific questions, they can lead to improved clinical practice. Understanding the wiring diagram of the retina can inform clinical studies of conditions such as glaucoma, and helps to give a rational basis for development of treatments. For example, dysfunction in blue-cone pathways is an early sign of glaucoma, so understanding the connections of blue-cone pathways in the fovea can lead to improved methods for early detection of this leading cause of blindness.Read moreRead less
Generation Of Complex Responses In Retinal Ganglion Cells
Funder
National Health and Medical Research Council
Funding Amount
$490,500.00
Summary
The retinal ganglion cells, whose axons form the optic nerve, comprise numerous distinct types, which respond to visual stimuli in either a simple or complex manner. The project will investigate how the complex responses of the direction-selective ganglion cells (DSGCs) and the local-edge-detector ganglion cells (LEDs) are generated. It appears that the retinal neurons providing inhibitory input to DSGCs and LEDs use different neurotransmitters, and the project will investigate how this shapes t ....The retinal ganglion cells, whose axons form the optic nerve, comprise numerous distinct types, which respond to visual stimuli in either a simple or complex manner. The project will investigate how the complex responses of the direction-selective ganglion cells (DSGCs) and the local-edge-detector ganglion cells (LEDs) are generated. It appears that the retinal neurons providing inhibitory input to DSGCs and LEDs use different neurotransmitters, and the project will investigate how this shapes the response properties of the ganglion cells. This will be done both by recording the visually evoked responses of the ganglion cells in an isolated preparation of the retina and by using two-photon laser-scanning microscopy to functionally image the neuronal interactions between the neurons that inhibit the DSGCs.Read moreRead less
The retina lines the back of the eye and sends multiple movies of the visual world to the brain. This project aims to investigate how these multiple information channels are created. Descriptions of the basic pattern of wiring in the healthy retina will help clinical researchers to understand the disruptions that occur in visual disease. The precision of normal retinal wiring also delineates the precision required to restore normal function to a diseased or degenerating eye.
Role Of Dendritic Information Processing In Visual Circuit Computations
Funder
National Health and Medical Research Council
Funding Amount
$895,244.00
Summary
Vision is the primary sensory modality in man, and its disturbance carries an enormous socio-economic burden. The dynamic operations of the neuronal assemblies that underlie vision are poorly understood, partly because of an incomplete description of the computational properties of visual neuronal circuits. The aims of the application are to mechanistically dissect defined computational operations of visual neural circuits using advanced electrophysiological and optical recording techniques.
Vestibulo-ocular Reflex Physiology, Pathology And Rehabilitation
Funder
National Health and Medical Research Council
Summary
A sensation of movement from the inner ear is used to stabilise vision during head movements. Without it, every time you walk, run, or drive on a bumpy road, the world would appear to bounce. It can be debilitating when this sense doesn't work due to various diseases. This research examines how this sense works normally and the factors important for self-repair after injury. This work will also develop training exercises using a device for take-home balance rehabilitation.
Mechanisms Of Body Representation And The Sensory Consequences Of Stroke
Funder
National Health and Medical Research Council
Funding Amount
$408,842.00
Summary
How does the brain control movement without vision? We cannot see our mouth but can easily put food in it. The brain uses a combination of sensory signals and stored models of the body, to control movement. The body models, and their interaction with sensory information, is not well understood. but they are disrupted by common clinical disorders. This research project investigates unsolved questions about the body model including how it is affected by stroke.
Functional Anisotropies In The Processing Of Orientation And Direction-of-motion By Human Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$366,164.00
Summary
We will study patterns of activity in the human brain to identify the cortical signature of normal visual function. The correspondences between patterns of brain activity and the structure and motion of the visual image in the normal human brain will provide data against which brain activity in a range of disorders from amblyopia to schizophrenia can be assessed.