Inhibition Of Fear Memories By Extinction: Neural Substrates.
Funder
National Health and Medical Research Council
Funding Amount
$234,250.00
Summary
Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relati ....Anxiety disorders [e.g., Post Traumatic Stress Disorder (PTSD)] are the most prevalent type of psychopathology in the industrialised world. They are associated with characteristic behavioural (e.g., heightened startle) and autonomic (e.g., cardiovascular) reactions. These disorders are often characterised as an inability to regulate the emotion of fear. Significant progress has been made in understanding the neural and cellular processes involved in the establishment of fear memories, but relatively little is known about the mechanisms by which fear memories can be inhibited or suppressed. Understanding this latter process is a key to the development of effective treatments for anxiety disorders such as PTSD where the patient suffers from persistent, intrusive, unwanted trauma memories. A common experimental procedure for reducing learned fear is to repeatedly expose the subject to a fear-eliciting stimulus but without any aversive outcome. This procedure leads to a progressive loss, or extinction, of the fear reactions elicited by the stimulus. Historically, the extinction of fear was thought to be due to an erasure of the fear memory. However, recent evidence shows that extinction inhibits, rather than erases, the fear memory. Because the fear memories remain intact, some structure(s) in the brain must inhibit activity in the fear pathway. This project uses extinction of conditioned fear reactions in rat subjects to determine the structure(s) in the brain that inhibit fear memories and their behavioural and cardiovascular expression. It brings together the expertise of four well-established researchers and uses a combination of behavioural, physiological, immunohistochemical, tract tracing, and lesion approaches to achieve this aim. The proposed experiments will reveal the structure(s) in the brain that control the inhibition of fear, as well as the site(s) of this inhibition in the fear pathwayRead moreRead less
Rhombomeric Topography of Structures in the Adult Mouse: Evidence from Avian Homologies and Transgenic Mice. The brainstem of birds has been shown to be formed by a line of segments, like carriages of a train. The same arrangement exists in the embryos of mammals, but is hidden in the adult mammalian brain. We will transfer our detailed knowledge of bird brains to make a maps of the brainstem segments in adult mice. We will then test this map with special gene markers which will reveal the occul ....Rhombomeric Topography of Structures in the Adult Mouse: Evidence from Avian Homologies and Transgenic Mice. The brainstem of birds has been shown to be formed by a line of segments, like carriages of a train. The same arrangement exists in the embryos of mammals, but is hidden in the adult mammalian brain. We will transfer our detailed knowledge of bird brains to make a maps of the brainstem segments in adult mice. We will then test this map with special gene markers which will reveal the occult segmental pattern in adult mice. This work will give us a new way of understanding the organisation of brainstem centres that control breathing, cardiovascular functions and emotional states.Read moreRead less
Sympathetic Control Of Cutaneous Blood Flow And Blood Pressure In Human Spinal Cord Injury
Funder
National Health and Medical Research Council
Funding Amount
$242,002.00
Summary
While spinal cord injury can cause devastating changes in the nervous system paralysis and loss of sensation relatively little is known about changes to the sympathetic nervous system. The sympathetic nervous system is intimately involved in the ongoing control of blood pressure, blood flow and temperature control. Loss of sympathetic control can occur following spinal cord injury. Interruption of descending pathways can result in partial or complete loss of sympathetic outflow from the thoracol ....While spinal cord injury can cause devastating changes in the nervous system paralysis and loss of sensation relatively little is known about changes to the sympathetic nervous system. The sympathetic nervous system is intimately involved in the ongoing control of blood pressure, blood flow and temperature control. Loss of sympathetic control can occur following spinal cord injury. Interruption of descending pathways can result in partial or complete loss of sympathetic outflow from the thoracolumbar segments. Complete decentralization can result in autonomic dysreflexia (autonomic hyperreflexia), in which sensory stimuli originating below the lesion evoke a reflex increase in sympathetic drive to the blood vessels, causing them to constrict. Because of this, blood pressure may rise suddenly and remain at such high levels that stroke and (occassionally) cardiac arrest may occur. This phenomenon, autonomic dysreflexia, is considered a medical emergency. The typical subjective signs of autonomic dysreflexia include a throbbing headache, tingling in the head or nasal congestion; sweating and flushing above the lesion are clinical signs that prompt medical staff to measure blood pressure and to locate the source of sensory irritation (usually a distended bladder or impacted colon, sometimes a pressure sore or ingrown toenail). Commonly, however, subclinical episodes go undetected, and this phenomenon of silent dysreflexia is of increasing concern. This project will develop means of assessing the integrity and state of the sympathetic nervous system below a lesion in patients with spinal cord injury and characterize the firing properties of reflexly activated sympathetic neurones.Read moreRead less
Towards a continuum model of orienting and defensive responses. Orienting (OR) and Defensive Responses (DR) underlie important survival functions of attending to unexpected stimuli and avoiding harm.We will establish the first integrative profile of human OR/DR function, using simultaneous recording of brain activity and 'body' responsivity. Given sex and age variation in OR/DRs, both males and females spanning six decades will be studied. OR/DR abnormalities are associated with major disorders ....Towards a continuum model of orienting and defensive responses. Orienting (OR) and Defensive Responses (DR) underlie important survival functions of attending to unexpected stimuli and avoiding harm.We will establish the first integrative profile of human OR/DR function, using simultaneous recording of brain activity and 'body' responsivity. Given sex and age variation in OR/DRs, both males and females spanning six decades will be studied. OR/DR abnormalities are associated with major disorders of attention and stress, which also vary with sex and age. We will examine relationships between OR/DR function and proneness to these disorders in healthy individuals. The results will provide a framework for developing prevention and intervention strategies.Read moreRead less
Mapping the connectome that controls blood pressure. The connections that an individual brain cell receives from other cells ultimately determines its behaviour. Using a revolutionary new technique, the project will create a map of the brain cells that control blood pressure.
The Structural Basis For Glutamate Transporter Function
Funder
National Health and Medical Research Council
Funding Amount
$373,144.00
Summary
Glutamate transporters are vacuum cleaners in the brain that suck the neurotransmitter glutamate into cells. When the glutamate vacuum breaks down or becomes blocked, glutamate levels outside cells increase, leading to cell death in the brain. This process underlies the damage in many brain diseases including Alzheimer’s disease and stroke. The aim of this project is to understand the mechanism of the glutamate vacuum cleaner so we can develop therapeutics to fix it when it breaks down.
Exploring the brain mechanisms underlying hyperactivity in Attention-Deficit/Hyperactivity Disorder. Attention-deficit/Hyperactivity Disorder (AD/HD) is the most common psychiatric disorder affecting children, resulting in substantial costs (both human and financial) to the child, their family and Australian society. The outcomes of this project will provide a better foundation for understanding dysfunctional brain mechanisms in AD/HD, which is expected to lead to better diagnosis, treatment, an ....Exploring the brain mechanisms underlying hyperactivity in Attention-Deficit/Hyperactivity Disorder. Attention-deficit/Hyperactivity Disorder (AD/HD) is the most common psychiatric disorder affecting children, resulting in substantial costs (both human and financial) to the child, their family and Australian society. The outcomes of this project will provide a better foundation for understanding dysfunctional brain mechanisms in AD/HD, which is expected to lead to better diagnosis, treatment, and community support. Ultimately this will contribute to a healthy start to life for these children. This project will also demonstrate how an integrated Australian approach can lead the research agenda in both basic neuroscience, at the interface of psychology and physiology, and its applications in health.Read moreRead less
Occupant comfort, cognitive performance and task performance in wind-excited tall buildings. Strong winds are sensitive to climate change and highly unpredictable, critically affecting the design of tall buildings and our built environment. The outcomes of this research will revolutionalise current design approach for occupant comfort in wind-excited tall buildings and deliver a new generation of tall buildings that provides a comfortable living and working environment without a degradation of w ....Occupant comfort, cognitive performance and task performance in wind-excited tall buildings. Strong winds are sensitive to climate change and highly unpredictable, critically affecting the design of tall buildings and our built environment. The outcomes of this research will revolutionalise current design approach for occupant comfort in wind-excited tall buildings and deliver a new generation of tall buildings that provides a comfortable living and working environment without a degradation of work performance due to wind-induced vibration. The transfer of this knowledge from research to practice will enhance the international competitiveness of our architecture, engineering and construction professionals, boosting our involvement in major tall building projects worldwide and bringing long-term economical benefits to Australia.Read moreRead less
External Therapeutic Device To Support Rehabilitation Of The Hand Following Trauma Or Surgery
Funder
National Health and Medical Research Council
Funding Amount
$175,000.00
Summary
The loss of hand function will affect every aspect of an individual’s life. This includes the ability to feed and care for themselves and the ability to work and participate in family life. For people recovering from problems such as trauma, burns or surgery affecting the hand, careful management of hand rehabilitation can influence the outcome for the patient significantly. In order to reduce the possibility of mobility difficulties occurring, including loss of joint range of motion, muscle and ....The loss of hand function will affect every aspect of an individual’s life. This includes the ability to feed and care for themselves and the ability to work and participate in family life. For people recovering from problems such as trauma, burns or surgery affecting the hand, careful management of hand rehabilitation can influence the outcome for the patient significantly. In order to reduce the possibility of mobility difficulties occurring, including loss of joint range of motion, muscle and tendon sheath adhesions or non-functional scar tissue formation, continuous passive motion (CPM) is often indicated. Additionally, for people with reduced mobility of the hand due to upper limb paralysis, such as those with cervical spinal cord injury, stroke, cerebral palsy or peripheral nerve injury, disregard for management of the maintenance of the joint range of motion of the effected hand will result in contracture and limited joint range of motion. Such syndromes will reduce hand function, which is already limited by paralysis, and will negatively affect potential outcomes for aggressive rehabilitation techniques, such as tendon transfer surgery and functional neuromuscular stimulation. Therefore, in such cases, CPM is also indicated. Current devices applying CPM have shown to be effective in minimising the syndromes indicated above and these results are summarised in the Background and Research Plan attached to this proposal. Unfortunately, the use of such devices is not always prescribed by clinicians. This is due, mainly, to the limitations of these devices that are in the marketplace. These limitations include lack of secure finger placement, lack of portability, the inability to provide specialised therapy to specific joints and inflexible programming. This proposal introduces an improved device to be developed and these improvements form the proposal aims below. Given such an improved device, which can overcome many of the problems with current CPM machines, it is likely that that the clinical application of CPM will achieve the greater degree of prescription and application in hand rehabilitation. These improvements should overcome the clinical reticence to use these devices and restore a balance by increasing their use to the level that the scientific literature indicates they should have. The overall aim of the proposal is to take the device to a stage where it is ready for clinical trial.Read moreRead less