Integrative Role Of Feedback Projections To Cat Primary Visual Cortex
Funder
National Health and Medical Research Council
Funding Amount
$293,321.00
Summary
Although in the last decade termed The Decade of the Brain we have learned a lot about the brain, the gaps in our understanding of brain functions are still enormous. The analysis of information in the sensory parts of the brain appears to be arranged in a distributed - hierarchical way. For example, different types of nerve fibres leaving the eye carry fairly generalised information about the external visual world along distinct parallel information channels. By the time the signals reach cereb ....Although in the last decade termed The Decade of the Brain we have learned a lot about the brain, the gaps in our understanding of brain functions are still enormous. The analysis of information in the sensory parts of the brain appears to be arranged in a distributed - hierarchical way. For example, different types of nerve fibres leaving the eye carry fairly generalised information about the external visual world along distinct parallel information channels. By the time the signals reach cerebral cortex there is a dramatic increase in complexity of visual stimuli to which cells respond (orientation, length and direction of movement of contours became important). There are at least two parallel feedforward information processing streams across the cerebral cortex involving a number of relay stations at each of which there are further specializations. For example, cells in one area appear to respond only to faces while in some other areas cells respond to motion in particular directions almost irrespective of the position of the stimuli. In the human there are more than 30 visual cortical areas. What is very surprising that from all these areas there are extensive feedback pathways running back to the lower-order areas. The feedback pathways appear to largely criss-cross different information processing streams and their function is very poorly understood. We will record from cells in lower-order areas noting the way they respond to different stimuli. Then we will block the feedback pathway from a particular higher-order area by cooling the area to about 10oC. We have confirmed that this prevents nerve impulses leaving the cooled area. Then we repeat our tests on the cell in the lower-order area. Comparing the responses with and without feedback activity will tell us what the feedback is doing. Understanding the function of feedback pathways hopefully would help us to understand the mechanisms underlying some subtle psychoneurological diseases.Read moreRead less
Interaction Between Symptoms Of Brainstem Disturbance, Sensory Disturbances And Pain In Migraine
Funder
National Health and Medical Research Council
Funding Amount
$165,509.00
Summary
Migraine affects about 18% of women and 6% of men across their lifespan and usually peaks during the most productive years of life. Although serious neurological effects of migraine are rare, some sufferers are left with permanent physical disability after attacks of migraine-related stroke. More common are debilitating side effects of medication, and the psychological and social disruption of experiencing recurrent attacks of migraine. Apart from the pain and distress experienced during migrain ....Migraine affects about 18% of women and 6% of men across their lifespan and usually peaks during the most productive years of life. Although serious neurological effects of migraine are rare, some sufferers are left with permanent physical disability after attacks of migraine-related stroke. More common are debilitating side effects of medication, and the psychological and social disruption of experiencing recurrent attacks of migraine. Apart from the pain and distress experienced during migraine, recurrent headaches are responsible for considerable health care costs and lost productivity. Thus, there are important economic and social reasons for developing new treatments, particularly treatments that reduce susceptibility to recurrent attacks. This project aims to investigate interactions among symptoms of migraine (head pain, nausea, and changes in facial blood flow), so that the sequence of symptom development can be studied systematically. We will induce motion sickness (which provokes nausea and many other symptoms of migraine), and then study the effects of head pain and strong sensory stimulation. We expect that migraine sufferers will report stronger symptoms and show greater physiological changes to these stimuli, either alone or in combination, than people who rarely suffer from headache. One of the most commonly recognized triggers of migraine is psychological stress. The aim of the second part of this project is to determine whether a substance released during stress (noradrenaline) heightens inflammation in scalp blood vessels, thus increasing the likelihood of migraine. We hope that this approach will help to identify the basis of the abnormality which increases susceptibility to migraine, so that it can be targeted for treatment.Read moreRead less
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
Are The Energy Expenditures Of Household And Garden Chores Of Sufficient Intensity To Confer Health Benefits?
Funder
National Health and Medical Research Council
Funding Amount
$322,110.00
Summary
Participation in regular moderate to vigorous intensity physical activity reduces risk for cardiovascular disease, non-insulin dependent diabetes, osteoporosis and some cancers. Recent epidemiological recommendations are that 30 minutes of moderate intensity physical activity (e.g. brisk walking at 4.8-6.4 km-hr) on most days is sufficient to confer these significant health benefits. However, many Australians spend substantial amounts of time engaged in household chores and gardening - yardwork ....Participation in regular moderate to vigorous intensity physical activity reduces risk for cardiovascular disease, non-insulin dependent diabetes, osteoporosis and some cancers. Recent epidemiological recommendations are that 30 minutes of moderate intensity physical activity (e.g. brisk walking at 4.8-6.4 km-hr) on most days is sufficient to confer these significant health benefits. However, many Australians spend substantial amounts of time engaged in household chores and gardening - yardwork activities but it is unknown whether the intensities of these activities are sufficient to confer the aforementioned health benefits. The aims of this study are therefore to: 1. Measure directly the energy cost of self-paced common household chores and gardening - yard activities. 2. Provide data that are required to estimate accurately the prevalence of 'adequate' levels of physical activity among adults. 3. Identify indirect methods (such as heart rate, motion and breathing frequency) which, in combination, are suitable for use in large scale surveys of activity levels. The outcomes of this study will be: 1. A greatly improved understanding of whether energy expenditure associated with self-paced household chores and gardening - yard activities is adequate to confer health benefits. 2. Our results will be used in key public health interventions which are aimed at modifying the physical activity levels of Australians. 3. If the public health message encourages some of the ~30% of sedentary Australians to undertake regular moderate intensity physical activity then this will: reduce the cost of the health care system, substantially reduce the premature loss of life and decrease morbidity and disability. 4. Our results will help public health epidemiologists to monitor the percentage of Australians who are adequately physically active.Read moreRead less