Neural Computations For Predictive Coding In Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$479,832.00
Summary
The project aims to use the principle of "predictive coding" - a theory that promises to be a unified theory of the brain - to understand how the visual cortex makes predictions about future events, at cellular level. This basic knowledge will not only shed light on how the cerebral cortex functions at the cellular level, but may also clarify the neuronal basis of mental conditions such as schizophrenia and autism.
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 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.
A Role For The Pulvinar Nucleus In Visual Cortical Development And Plasticity
Funder
National Health and Medical Research Council
Funding Amount
$844,435.00
Summary
This project will investigate a part of the brain responsible for processing visual information, the pulvinar. This area has received little attention but has more recently been associated with the capacity for infants to recover vision following injuries such as stroke, as well as in mental health conditions such as schizophrenia. We will take a cell-to-system approach to uncover how this area develops and modulates the processing of visual information.
Rapid Plasticity In Sensory Systems - Linking Neuronal Adaptation And Perception
Funder
National Health and Medical Research Council
Funding Amount
$650,810.00
Summary
The activity of individual sensory neurons in the brain is surprisingly variable and continuously changing. It is unclear how reliable perception of the world can be generated from the activity of “noisy” neurons, and it remains unclear why neuronal sensitivity should change in the first place! This project will give insights into how groups of sensory neurons collectively overcome their intrinsic variability to support reliable visual perception.
Neural Basis Of The Functions Of The Primary Visual Cortex: Roles Of Feedforward And Intracortical Inputs
Funder
National Health and Medical Research Council
Funding Amount
$486,280.00
Summary
Signals from the eyes undergo extensive processing at the level of the primary visual cortex so that basic features in the scene such as lines, edges, colours and movement are coded in the activity of individual neurones. This project aims to further our understanding of this process at the basic cellular level. This will not only enable interventions that would help those with poor sight but also give us an insight into basic brain circuitry and its derangement in many neurological disorders.
Understanding The Organisation Of The Medial Parietal Cortex: Sensorimotor Integration For Goal-directed Behaviour
Funder
National Health and Medical Research Council
Funding Amount
$551,862.00
Summary
Reaching and grasping are of obvious significance for a productive life, and many of the brain areas known to be involved in the direction of arm movements are located in the parietal lobe. Stroke affecting this part of the brain causes disability, as people become unable to reach accurately, or to close their hands around objects with appropriate strength. This project will combine modern physiological and anatomical methods to reveal the brain circuitry responsible for such crucial skills.
Mechanisms And Pathways Leading To Saccadic Suppression In Primate Brain
Funder
National Health and Medical Research Council
Funding Amount
$858,086.00
Summary
Only the central few degrees of the visual field are viewed in high resolution. Consequently, the eyes must be pointed at targets of interest using saccadic eye movements. Each saccade generates potentially disturbing image motion but this is never perceived: saccadic suppression. This project aims to characterise the neural basis of saccadic suppression using modern techniques. As a result, a prime question in Neuroscience for over 100 years can now be answered.
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.
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