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
A novel sensory neural circuit has been identified innervating the airways and lungs. The anatomical organisation of this circuit has been described to some extent in previous studies, however there is a significant gap in knowledge with respect to its functional importance. This project will develop methods to address this knowledge gap and in doing so the project will firstly describe how this circuit controls breathing under normal conditions and secondly how this becomes dysregulated during
How Intestinal Motility Activates Sensory Pathways
Funder
National Health and Medical Research Council
Funding Amount
$555,875.00
Summary
Pain and discomfort from the gut are common and unpleasant. We understand how gut sensory nerve cells work, at the cellular, molecular and genetic level. However, movement of the gut wall and contents are the major cause of activation of sensory neurons. We know little about which particular patterns of movement cause pain. This is crucial information for accurately diagnosing human gut disorders, for monitoring effectiveness of treatments and for identifying potential new drug targets.
How The Lateral Habenula Integrates Behavioral And Autonomic Functions: The VTA Dopamine Connection
Funder
National Health and Medical Research Council
Funding Amount
$819,904.00
Summary
When adverse events occur, the lateral habenula, an old brain nucleus, helps calculate the wisest corrective action by contributing to the “brake” that controls the brain’s dopamine reward system. Our research will show how the lateral habenula links corrective changes in behavior with coordinated changes in temperature. Understanding this link will greatly contribute to understanding the brain mechanisms that regulate our physiology during stressful situations and as part of mental illness.
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
How the gut nervous system interacts with bacteria. This project aims to reveal how the enteric nervous system of the gastrointestinal (GI) tract interacts with the gut microbiota. Gut function has largely been studied without considering microbiota. The project will use genetically modified animal models, image analysis of gut motility and sequencing of gut microbes, and develop neurophysiological methods to understand gut function. Expected benefits include better understanding of mechanisms u ....How the gut nervous system interacts with bacteria. This project aims to reveal how the enteric nervous system of the gastrointestinal (GI) tract interacts with the gut microbiota. Gut function has largely been studied without considering microbiota. The project will use genetically modified animal models, image analysis of gut motility and sequencing of gut microbes, and develop neurophysiological methods to understand gut function. Expected benefits include better understanding of mechanisms underlying antibiotic resistance, risks associated with discretionary caesarean sections and the benefits of breastfeeding.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.
Development of sympathetic nerve pathways. The mature nervous system contains many types of neurons connected in precise ways. Developing neurons must make many decisions about what type of neuron to become and what connections to make. This study looks at the mechanisms that guide the developing neurons in these important decisions.
Neural migration: Which cells advance and which stay behind? This project aims to examine the neural crest cells that colonise the developing gut and to identify why some cells advance while others stay behind to populate a region. Directed cell migration is essential for normal development, including for the nervous system. In most of the migratory cell populations that have been analysed to date, all of the cells migrate as a collective from one location to another. However, there are also mi ....Neural migration: Which cells advance and which stay behind? This project aims to examine the neural crest cells that colonise the developing gut and to identify why some cells advance while others stay behind to populate a region. Directed cell migration is essential for normal development, including for the nervous system. In most of the migratory cell populations that have been analysed to date, all of the cells migrate as a collective from one location to another. However, there are also migratory cell populations that must populate the areas through which they migrate, and thus some cells get left behind while others advance. The planned data are likely to be relevant to other cell populations that also populate the areas through which they migrate, including neural crest-derived melanocytes and Schwann cell precursors.Read moreRead less
The Identification Of Thoracic Targets For Prevention And Intervention In Bronchopulmonary Dysplasia
Funder
National Health and Medical Research Council
Funding Amount
$316,449.00
Summary
The persistence of breathing problems from infancy to later life is a complication of premature birth with lifelong consequences. Breathing problems often occur together with lung disease, but prematurity can also affect heart and blood vessel development, and weakness of the main breathing muscle. We will find out how much the heart, lungs and diaphragm contribute to breathing problems in babies; helping us to better predict, diagnose and treat severe breathing problems in babies born preterm.