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
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.
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.
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.
Context Is Everything – Understanding How Spatial, Temporal And Behavioural Context Affect Sensory Processing
Funder
National Health and Medical Research Council
Funding Amount
$512,382.00
Summary
A possum in a tree is cute to see on a bushwalk, but scary to hear when we are trying to sleep. This illustrates that how we perceive a “target” is affected by “modulators” that are close in space or time to the target, or by the task at hand. Deficits in contextual modulation are apparent in many neurological conditions. This project will investigate the neural circuitry that mediates spatial, temporal and task-related contextual modulation.
The Pulvinar Is Instrumental In The Development Of Visual Cortical Networks
Funder
National Health and Medical Research Council
Funding Amount
$1,192,911.00
Summary
This Project will elucidate the mechanisms and brain structures involved in visual system development and how their perturbation in early life can lead to neurodevelopmental and cognitive brain disorders, such as Williams and fragile-X syndromes as well as dyslexia. Furthermore, it will demonstrate how the visual brain has a greater capacity to compensate and achieve preservation of vision following an injury in early life.
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.
Cortical Excitation In Migraine: Using Vision To Understand And Track Brain Excitability
Funder
National Health and Medical Research Council
Funding Amount
$521,628.00
Summary
Migraine is a common neurological condition affecting approximately 15% of adults. Therapies are most effective if used early, yet many people are unable to predict their migraines or to recognize early signs. In addition to headache, key symptoms include abnormal visual and auditory experience. We propose that aspects of vision and hearing will vary systematically according to the current brain status. Our translational goal is to develop tests that allow individuals to better manage migraine.
Eye Movements And The Neural Representation Of Visual Space
Funder
National Health and Medical Research Council
Funding Amount
$459,061.00
Summary
This project will investigate the brain mechanisms that underlie our ability to perceive the locations of objects using vision. This fundamental ability supports a range of important functions including visually-guided reaching, navigation during walking, and spatial awareness, but remains poorly understood. Using physiological, behavioural, and analytical methods, this project will fill a key knowledge gap in visual neuroscience and form a basis for a range of clinical and biomedical advances.
Interaction Of Thalamic And Cortical Activity In The Primate Visual System
Funder
National Health and Medical Research Council
Funding Amount
$487,580.00
Summary
We recently discovered that a primitive part of the visual pathway shows rhythmic nerve cell activity similar to slow brain waves recorded in sleep, anaesthesia, and epilepsy. We now plan to discover whether these primitive cells help to generate brain waves by measuring the timing of their activity together with brain waves in different visual and non-visual parts of the brain. This project will contribute to understanding the role of brain waves in normal brain function and epilepsy.