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.
Neuronal Activity And Variability Underlying Perception And Action
Funder
National Health and Medical Research Council
Funding Amount
$349,802.00
Summary
Perception and behaviour are often unpredictable. We do not identically perceive repeated stimuli, and even professional athletes cannot precisely replicate their actions. This project compares variations in the activity of motion-sensitive neurons in the brain with variability in motion perception and eye movements. This should give insights into how neuronal activity underlies conscious perception and eye movements and may ultimately help treat conditions with impaired control of movement.
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.
The roles of spectral cues and auditory plasticity in auditory localisation, speech segregation and speech intelligibility. Our recent work shows that high frequency energy in speech is important for the localisation of speech and may also aid in improving speech intelligibility in noisy environments. The work proposed here will systematically explore this somewhat surprising new finding and the results will be incorporated into a predictive model of speech intelligibility under spatial listenin ....The roles of spectral cues and auditory plasticity in auditory localisation, speech segregation and speech intelligibility. Our recent work shows that high frequency energy in speech is important for the localisation of speech and may also aid in improving speech intelligibility in noisy environments. The work proposed here will systematically explore this somewhat surprising new finding and the results will be incorporated into a predictive model of speech intelligibility under spatial listening conditions. This work includes a systematic study of auditory functional plasticity to changes in the spatial cues. Taken together, the outcomes of this work will unlock a range of new approaches to enhancing spatial hearing in multi-channel communication devices and spatial hearing aids.Read moreRead less
Acoustic, spatial and informational cues used to solve the cocktail party problem. Speech is the principal mode of human communication and yet we understand little about how we are able to concentrate on one talker against a noisy background. Significant improvements in supporting listening by the hearing impaired, in teleconferencing systems and computer speech interfaces are dependent on a more advanced understanding of how we solve this cocktail party problem. This research explores the acous ....Acoustic, spatial and informational cues used to solve the cocktail party problem. Speech is the principal mode of human communication and yet we understand little about how we are able to concentrate on one talker against a noisy background. Significant improvements in supporting listening by the hearing impaired, in teleconferencing systems and computer speech interfaces are dependent on a more advanced understanding of how we solve this cocktail party problem. This research explores the acoustic, spatial and informational cues used by the healthy auditory system to achieve this remarkable feat of signal processing. There is significant potential for commercialization of the IP that will arise from this research.Read moreRead less
Signals And Noise: A Study Of The Neurocognitive Mechanisms Underpinning Habituation To Noise In Normal And Damaged Hearing
Funder
National Health and Medical Research Council
Funding Amount
$408,938.00
Summary
McLachlan and Wilson recently published the first model of hearing that combines brain structure with function. This model postulates that recognition mechanisms initiate first, and then regulate the processing of other features. This project will investigate whether recognition mechanisms enable the auditory system to adapt to repetitive (background) noise by predicting and inhibiting responses to these sounds, and any changes in these mechanisms that may accompany hearing damage and tinnitus.
The Role Of Corticothalamic Feedback On The Response Dynamics Of Thalamic Neurons
Funder
National Health and Medical Research Council
Funding Amount
$351,852.00
Summary
A fundamental question in neuroscience is how the brain selectively processes sensory information to generate a reliable representation of the world. Positioned in the centre of the brain, the thalamus plays a key role in sensory processing. This project investigates how the interaction between thalamus and cortex shapes the selection and gating of sensory information. This is a fundamental question in basic neuroscience with the potential to increase our knowledge about attentional deficits.
The Role Of Dopamine And Other Neuromodulators As Light Signals In The Inner Retina: A Link To Night Blindness Disorders
Funder
National Health and Medical Research Council
Funding Amount
$250,250.00
Summary
Although most human activities can be performed at night as efficiently as during daytime due to the use of artificial light, normal function of the circuits underlying night vision is critical. For example, when driving at night in a poorly illuminated road where the region illuminated by the headlights is processed by the cone circuit that serves daylight in the retina whilst the peripheral areas are processed by the rod driven nighttime circuit. Impairment of night vision and of the dark-ligh ....Although most human activities can be performed at night as efficiently as during daytime due to the use of artificial light, normal function of the circuits underlying night vision is critical. For example, when driving at night in a poorly illuminated road where the region illuminated by the headlights is processed by the cone circuit that serves daylight in the retina whilst the peripheral areas are processed by the rod driven nighttime circuit. Impairment of night vision and of the dark-light switch can have fatal consequences. Night blindness is a symptom characterised by reduced vision in the dark and slow adaptation to dim light. Some congenital night blindness disorders are caused by mutations in the photoreceptor calcium channels which mediate signal transmission. Additionally, patients treated with neuroleptics, a group of drugs which affect the dopaminergic system, suffer night vision disorders. Dopamine acts as a light signal in the retina. AII amacrine cells are pivotal neurones for night vision segregating two channels (ON and OFF) which convey visual information. AII cells are modulated by dopamine and thus, represent interesting targets to study the role of dopamine in the dark-light switch. Much is know about the action of dopamine on transmission of ON signals channelled by AII cells. However, its action on the OFF channel is largely unknown. We believe that some night vision disorders originate by imbalance in the dopaminergic system in the retina and its effects on AII cells. We will test our hypothesis by studying the modulatory effect of dopamine on calcium dependent signal transmission between AII cells and their partners in the OFF channel. Our hypothesis will be further tested by using animal models in which dopamine receptor function is altered. The results of these studies will provide us with an invaluable model to understand the physiological basis of the dark-light switch and of the role of dopamine in night vision disorders.Read moreRead less
This is a study of the senses which arise from our muscles and which tell us where our different body parts are, at any point in time. These senses, collectively called proprioception, are also involved in the automatic, unconscious control of our muscles. So, ultimately, they allow us to stand and to move freely with precision and confidence, even in the dark. One of these senses, the sense of effort or of heaviness, is believed to be generated within the brain. It intensifies when we become fa ....This is a study of the senses which arise from our muscles and which tell us where our different body parts are, at any point in time. These senses, collectively called proprioception, are also involved in the automatic, unconscious control of our muscles. So, ultimately, they allow us to stand and to move freely with precision and confidence, even in the dark. One of these senses, the sense of effort or of heaviness, is believed to be generated within the brain. It intensifies when we become fatigued. These experiments will be concerned with finding out more about how this works. We have a method that uses magnetic stimulation of the brain to change its control of our muscles. Using it we will learn how this sense is generated. When we close our eyes and move our limbs we realise that we know exactly where they are at any point in time. It remains uncertain exactly how this information is generated within the nervous system. One idea, arising from some recent experiments which we want to test, is that as we move the limb, the skin over the moving parts is stretched and stretch-sensitive nerve endings in the skin provide us with information about the movement. Alternatively, perhaps it is the effort we exert to maintain limb position against the force of gravity which tells us where the limb is. In another recent study we have found that when a muscle has become painful from excessive exercise or from some local strain injury, our ability to control the muscle and so move the limb is no longer as effective. We want to study the underlying nervous mechanisms responsible for the changes in movement control. Are they designed to spare the muscle while it recovers from injury? How are they brought about? All of this work is important for a better understanding of ourselves, for a better clinical diagnosis when something goes wrong and for improved treatment of diseased or injured muscles.Read moreRead less
Cochlear Type II Neurons In Contralateral Suppression
Funder
National Health and Medical Research Council
Funding Amount
$459,434.00
Summary
Sound in one ear affects hearing in the other ear. This contralateral suppression is important for hearing attention and protection from noise damage. We will test the hypothesis that cochlear type II sensory neurons provide the sensory input for this process using models where neuronal development is altered, or the neurons are removed. The study addresses hearing disability in society, facilitating cochlear prosthesis development and the understanding of hearing loss.