Effects Of Saccadic Eye Movements On Perception And Visual Memory.
Funder
National Health and Medical Research Council
Funding Amount
$255,750.00
Summary
We all make rapid eye movements, called saccades, three times a second all our waking lives. They allow us to direct our gaze at what catches our attention, but they sweep images across our retinas and alter all the linkages between the eyes and the brain. The question at the heart of this project is how the visual system maintains perceptual stability given the disruption to the flow of visual input that saccades necessarily cause. It has to do more than suppress disturbing signals; it has to l ....We all make rapid eye movements, called saccades, three times a second all our waking lives. They allow us to direct our gaze at what catches our attention, but they sweep images across our retinas and alter all the linkages between the eyes and the brain. The question at the heart of this project is how the visual system maintains perceptual stability given the disruption to the flow of visual input that saccades necessarily cause. It has to do more than suppress disturbing signals; it has to link the present with the past. In recent years we and others have made substantial progress toward answering this question. In this project we plan a four-pronged attack that will take us further. We anticipate that our results will reveal how the visual system maintains and adjusts its representations of space and time, integrates signals from before and after saccades, and regulates the flow of information from memory to achieve a seamless melding of the present with the past. This project is not directed at any particular clinical problem, but disturbances of perception and memory are aspects of many clinical conditions. If we succeed in our aims what we discover will constitute a major scientific discovery which should find application to many conditions in which perception and memory are disturbed, from dyslexia to brain damage and even affective disorders such as schizophrenia and depression.Read moreRead less
Mechanisms Of Mechanotransduction In Primary Visceral Afferents
Funder
National Health and Medical Research Council
Funding Amount
$253,500.00
Summary
Mechanotransduction is the process whereby mechanical stimuli are converted into signals in sensory nerves. This forms the basis of touch, hearing, position sense and many aspects of internal perception. It also constitutes a major component of pain. Our group aims to discover the molecular basis of mechanotransduction in mammals, and in particular how it relates to signaling of events in the digestive system. We and our collaborators have been among the first to explore this question, and have ....Mechanotransduction is the process whereby mechanical stimuli are converted into signals in sensory nerves. This forms the basis of touch, hearing, position sense and many aspects of internal perception. It also constitutes a major component of pain. Our group aims to discover the molecular basis of mechanotransduction in mammals, and in particular how it relates to signaling of events in the digestive system. We and our collaborators have been among the first to explore this question, and have found that three genes are responsible for many aspects of mechanotransduction. Each gene is transcribed to produce a channel or pore in the membrane of sensory nerve fibres which responds to mechanical forces by allowing ions to enter and induce electrical signals. Our early findings in mice with disruption of individual genes indicate that a complex positive and negative interaction of these channels must underlie normal mechanotransduction. However, these channels must represent only a part of the transduction mechanism, with extracellular and intracellular anchors inevitably playing a major role. The identity of such anchoring proteins in mammals is currently emerging, and we are fortunate to have access to mice deficient in specific genes that will provide information about candidates for this role. Through our studies on mechanotransduction in the digestive system in parallel with our collaborators' studies on mechanotransduction in skin we shall not only identify the fundamental mechanisms of mammalian mechanotransduction, but also reveal which components of mechanotransducers are peculiar to the gut. Such peculiarities provide molecular targets for therapy of diseases in which alteration of mechanosensory signaling is itself an aim.Read moreRead less
Interaction Of TRP Channels And Inflammatory Mediators: A Critical Role In Visceral Pain
Funder
National Health and Medical Research Council
Funding Amount
$308,747.00
Summary
Transient receptor potential, or TRP channels, are involved in generating many of the sensations we feel, such as touch and pain. The function of these channels can be altered by substances released by the body during inflammation. Some TRP channels have specialized roles in signalling pain from the colon which can be enhanced during colonic inflammation. Understanding how TRP channels and inflammatory mediators function and interact is essential if we are to find treatments for colonic pain.
One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. We will address one particular aspect of this problem, namely the organisation of the cortical areas that provide visual control for skilled movement ....One of the main trends in the evolution of the primate brain was the huge expansion of the cortical areas devoted to visual processing. However, the exact role of individual areas remains highly controversial, making detailed physiological and anatomical studies in suitable primate models a key step to elucidating their function in the human brain. We will address one particular aspect of this problem, namely the organisation of the cortical areas that provide visual control for skilled movements. It is proposed that there are two parallel brain circuits involved in the analysis of motion, one tracking the movement of objects, and the other analysing a person s self-motion. Consider, for example, the task of a tennis player who has to return a serve. In order to achieve this, the brain must precisely integrate information about the ball s motion, as well as information about the player s speed and direction. This requires precise control of eye movements (to keep the eyes on the ball), as well as the ability to control the limb and trunk muscles. The aim of this study will be to map the anatomical framework underlying our ability to process all the relevant visual motion information, and to coordinate the appropriate motor responses. Such work is fundamental for understanding the functional organisation of the brain. It also has the potential to lay the groundwork for developments in areas of applied research, including medicine (e.g. the design of better rehabilitation strategies for people with brain damage), robotics- artificial intelligence (e.g. the improvement of artificial systems capable of vision), and the cognitive sciences (e.g. a better understanding of factors that limit human responses to visual stimuli).Read moreRead less
Interactions Of Gastric Hormones With Vagal Afferent Pathways And The Role Of This System In Obesity
Funder
National Health and Medical Research Council
Funding Amount
$550,918.00
Summary
When we feel full after a meal it is the result of a variety of different nerve signals from the gut in response to distension of the stomach and specific nutrients. These signals are disordered in obesity and this project aims to find out how to correct this problem in this modern day epidemic.
Peripheral Neuropathy And Pain: Role Of The Sphingosine Kinase-sphingosine 1-phosphate System
Funder
National Health and Medical Research Council
Funding Amount
$282,905.00
Summary
Understanding the neural mechanisms that generate pathological pain remains one of the essential goals for the development of effective treatments for pain, chronic pain with less side effects. Lipids are able to modulate pain perception. We will determine the role of a molecule named sphingosine 1-phosphate as a basis for the development of therapies for the treatment of neuropathic pain.
Transient Receptor Potential Channels (TRPs) As Transducers And Targets In Primary Visceral Afferents
Funder
National Health and Medical Research Council
Funding Amount
$669,130.00
Summary
Transient receptor potential, or TRP channels, are involved in generating many of the sensations we perceive, such as heat, cold, touch and pain. Some TRP channels are specialized to signal pain from visceral organs, which we must investigate if we are to find treatments for visceral pain, which are currently lacking.
Signalling Of Muscle Force By Golgi Tendon Organs During Exercise And Fatigue
Funder
National Health and Medical Research Council
Funding Amount
$181,320.00
Summary
It is a common experience for objects being carried to feel heavier and tasks needing muscular effort to become more difficult as one becomes tired and the muscles fatigue during exertion. The sensation of muscle force depends on two factors. One, a sense of the effort required to perform a task, is generated in the central nervous system and. The other, a sense of the force actually developed by the muscles, is generated in the muscles themselves by signals from sensory receptors called Golgi t ....It is a common experience for objects being carried to feel heavier and tasks needing muscular effort to become more difficult as one becomes tired and the muscles fatigue during exertion. The sensation of muscle force depends on two factors. One, a sense of the effort required to perform a task, is generated in the central nervous system and. The other, a sense of the force actually developed by the muscles, is generated in the muscles themselves by signals from sensory receptors called Golgi tendon organs. The sensation of muscle force and the heaviness of objects results from a combination of both senses, but the contribution of each is unknown. The aim of the project is to determine whether the disturbance of force sense in fatigued muscles results from changes in the way tendon organs signal the actual force developed by the muscles. This will be important for understanding how force sense is disturbed following exercise and in disease states, and for understanding the normal way muscle force is sensed in everyday situations. Disturbances of force sense after exercise will be documented in human subjects by asking them to generate what they perceive to be equal forces in both arms or legs, before and after one limb only is exercised. Errors in force estimation will show up as mismatches between the two limbs. The difficulty with human experiments is that the signals generated by tendon organs cannot be measured directly, but only inferred, perhaps wrongly. This difficulty will be overcome by measuring tendon organ activity directly in anaesthetised animals, where the muscles will be electrically stimulated to perform exercise similar to that in the human experiments. A change in tendon organ signalling will be taken to mean that similar changes in humans could be responsible for disturbances of force sense. In further experiments, the mechanism of the changes will be explored.Read moreRead less
Examining The Role Of ASIC Channels In Pain Through The Development Of Subtype-specific ASIC Channel Modulators.
Funder
National Health and Medical Research Council
Funding Amount
$617,256.00
Summary
Acid sensing ion channels (ASICs) sense changes in acidity in the body. They are found throughout the body and may underlie nerve damage in stroke and some types of pain. ASICs also have many as yet unknown functions. A lack of selective tools to study ASICs is a major barrier to a complete understanding of what they do. This proposal aims to modify three animal toxins which block these receptors to make useful tools to study their function, in particular their role in sensing pain.