Representation Of Spatial Coordinate Systems Within Posterior Parietal Cortex And Hippocampus
Funder
National Health and Medical Research Council
Funding Amount
$43,759.00
Summary
To accurately reach for an object or walk from one room to another, our brains need to be able to locate objects around us and detect obstacles in our path. Our amazing ability to make an accurate eye movement directly towards an object such as a cup of tea and move our hand smoothly and directly to the cup is something we all take for granted. However, this ability requires enormous computational complexity which our brains have evolved to handle with ease. We plan to determine the parts of the ....To accurately reach for an object or walk from one room to another, our brains need to be able to locate objects around us and detect obstacles in our path. Our amazing ability to make an accurate eye movement directly towards an object such as a cup of tea and move our hand smoothly and directly to the cup is something we all take for granted. However, this ability requires enormous computational complexity which our brains have evolved to handle with ease. We plan to determine the parts of the brain that perform these computations by using a relatively new technique called functional magnetic resonance imaging or fMRI. This is a non-invasive technique that requires a person to lie in an MRI scanner and perform simple eye movement tasks while the scanner takes images of the brain. With this technology we are able to determine which regions of the brain are most active during the performance of each task, thereby giving us an insight into how the brain works. An area of the brain called the parietal lobe is thought to be involved in the localization of objects, such as reaching for a cup of tea. We will study this area using fMRI to determine how a map of space is represented within the parietal lobe. This region of the brain communicates with another region, the hippocampus which is thought to be involved in navigation, such as walking about the house or driving in the city. Functional MRI will be used to study the hippocampus of our subjects while they perform simple navigational tasks through a maze which is simulated on a computer screen. This will reveal the role hippocampus plays in navigation and the relationship between the parietal lobe and hippocampus. We hope that the greater understanding of hippocampus that will arise from this study will enable us to devise a robust method for imaging hippocampal function with fMRI. We expect that these techniques will aid in the diagnosis of hippocampal abnormalities in patients with temporal lobe epilepsy.Read moreRead less
Plasticity Of Sensorimotor Representations In Adult Primate Cortex
Funder
National Health and Medical Research Council
Funding Amount
$554,656.00
Summary
Cells in some regions of the brain, collectively known as the sensorimotor cortex, control our capacity to purposefully move the arms and hands. Damage to these regions in adults causes severe deficits. However, rehabilitative training can restore some control over the muscles. To understand how the brain circuits change to compensate for injury, and what effect rehabilitation may have on these changes, I will study cellular alterations in the movement control pathways in the cerebral cortex.
NEURONAL RESPONSES ELICITED BY VIEWING HUMAN BODY MOTION AND GESTURE.
Funder
National Health and Medical Research Council
Funding Amount
$135,822.00
Summary
This project aims to study human brain regions active in viewing movements of the body, face and hands, as well as gestures (i.e. movements with meaning). We will map the location of these human motion sensitive brain regions relative to brain areas dealing with other visual functions. We will use a new method of brain scanning (functional MRI) and recordings of the electrical activity of the brain to achieve these goals. Subjects for this project will be epilepsy patients undergoing investigati ....This project aims to study human brain regions active in viewing movements of the body, face and hands, as well as gestures (i.e. movements with meaning). We will map the location of these human motion sensitive brain regions relative to brain areas dealing with other visual functions. We will use a new method of brain scanning (functional MRI) and recordings of the electrical activity of the brain to achieve these goals. Subjects for this project will be epilepsy patients undergoing investigation for seizure surgery at the A and RMC and Royal Children's Hospitals in Melbourne. Functional MRI - a new non-invasive method for studying brain function - will locate the brain structures involved in the detection and analysis of human motion. Recording electrodes are surgically placed inside the brains of these patients in order to find the source of their seizures, and these electrodes will be utilised for this study. A number of facial, hand and body movement and gestural stimuli will be used. First, brain locations responding to face, hand and body movements will be identified. It is predicted that regions sensitive to hand motion could be located near areas known to participate in adjusting the subject's own visually-guided reaching behaviour. Similarly, regions sensitive to facial motion could be located near areas thought to deal with lip-reading. Second, differences in brain activity to gestures and movements of the face and hand will be studied, so as identify brain regions that process increasingly complex information. Third, differences in brain responses to incompatible (e.g. head facing left and moving right) versus compatible human motion will be studied. A brain 'map' with locations of these human motion sensitive regions relative to visually sensitive regions will be generated. These data will not only aid planning for future seizure surgery, but have implications for our understanding of the visual aspects of motor apraxia.Read moreRead less
Auditory Attentional Processes In Stroke Patients With Unilateral Neglect And In Normal Listeners
Funder
National Health and Medical Research Council
Funding Amount
$281,900.00
Summary
A common consequence of a stroke affecting the parietal lobe of the right hemisphere of the brain is a failure to attend to stimuli presented to the left side of the patient. This disorder, called unilateral spatial neglect, affects up to 50% of all stroke sufferers, and poses a significant problem for recovery of function. Neglect has been most widely studied in the modality of vision. Although neglect of auditory stimuli and of stimuli in other modalities has been reported, it has been studied ....A common consequence of a stroke affecting the parietal lobe of the right hemisphere of the brain is a failure to attend to stimuli presented to the left side of the patient. This disorder, called unilateral spatial neglect, affects up to 50% of all stroke sufferers, and poses a significant problem for recovery of function. Neglect has been most widely studied in the modality of vision. Although neglect of auditory stimuli and of stimuli in other modalities has been reported, it has been studied in much less detail, and the relationship between visual and auditory neglect has not been investigated using tasks of similar complexity. One aim of this project is to examine the relationship between auditory and visual neglect using tasks that are carefully matched for complexity and cognitive demands. A second aim relates to the important recent discovery that substantial changes in a visual scene can go unnoticed unless the observer's attention is drawn to them, a phenomenon termed change blindness. The project will examine the ability of normal listeners and of stroke patients to detect changes in complex auditory environments in which sounds arise from multiple sources located in different regions of space. We aim to establish whether there is a change deafness phenomenon analogous to change blindness, and if this is exacerbated in stroke patients with neglect. The results of this project will increase our understanding of the nature of normal auditory attentional processes and of their disruption as a consequence of stroke. The importance of these studies derives from the fact that hearing and attention to auditory stimuli serve a critical role in human communication and as an early warning system for events in the environment that are not within a person's visual field. Increased understanding of disturbances in auditory attention in neglect patients could lead to better rehabilitation of neglect, for which there is currently no effective treatment.Read moreRead less
Visuomotor Integration In The Medial Parietal Cortical Areas
Funder
National Health and Medical Research Council
Funding Amount
$665,163.00
Summary
This project will find out how the electrical activity of brain cells is used to direct the arms to a specific position in the space around a person's body. By understanding the code used by brain cells to perform this control of the arms, we will be able to "read" the brain activity directly, and use it to allow control of artificial arms by people who have been paralysed or had amputations.
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.