Fear Relapse: Neural Substrates Underlying Its Inhibition And Prevention
Funder
National Health and Medical Research Council
Funding Amount
$437,476.00
Summary
Exposure-based therapies are effective for anxiety disorders such as post traumatic stress, but two challenges remain: 1) patients that have learned to inhibit their fear are likely to relapse, requiring further therapy; 2) many drop out of therapy since it is aversive and anxiety provoking. We use an animal model to: 1) identify the neural substrates underlying fear inhibition; and 2) determine the conditions that prevent relapse and encourage participation in treatment.
The Effect Of Oxytocin On The Formation, Expression And Inhibition Of Fear Memories
Funder
National Health and Medical Research Council
Funding Amount
$390,243.00
Summary
Oxytocin is a hormone peptide which reduces amygdala activation to threatening stimuli and reduces anxiety in people and laboratory rodents. These results suggest that oxytocin could be a valuable pharmacological adjunct to exposure-based therapy for anxiety disorders. However, several questions must be answered before its therapeutic potential can be determined. As such, this project examines the effects of oxytocin on fear-related behaviours in rats, and neural fear circuits in the amygdala.
The Extinction Of Conditioned Fear And Its Implications For Cue Exposure Therapy
Funder
National Health and Medical Research Council
Funding Amount
$322,430.00
Summary
This project studies extinction of Pavlovian conditioned fear reactions in rats. Extinction of these reactions is an animal model for exposure therapy used in the treatment of anxiety disorders in people. In exposure therapy, the patient, aided by the clinician, confronts trauma-related cues in the absence of any overt danger. The intention of this therapy is to reduce the ability of the trauma-related cues to provoke the fear reactions that are undermining the patient's quality of life. In Pavl ....This project studies extinction of Pavlovian conditioned fear reactions in rats. Extinction of these reactions is an animal model for exposure therapy used in the treatment of anxiety disorders in people. In exposure therapy, the patient, aided by the clinician, confronts trauma-related cues in the absence of any overt danger. The intention of this therapy is to reduce the ability of the trauma-related cues to provoke the fear reactions that are undermining the patient's quality of life. In Pavlovian conditioning, subjects (typically rats) are exposed to a signaling relation between an initially neutral stimulus (e.g., a noise) and a feared outcome (e.g., foot shock). When later repeatedly exposed to the initially neutral but now feared stimulus (the noise) in the absence of the feared outcome, the fear reactions it acquired progressively decline until eventually it fails to elicit any such reactions. The fear reactions are said to have been extinguished. There has been significant progress in understanding the psychological processes and neural mechanisms underlying the acquisition of fear reactions, but much less is known about the processes and mechanisms underlying the extinction of these reactions. The project has two general objectives. The first is to determine the conditions of extinction training that promote long-term loss of fear reactions. The second objective is to determine how the brain controls this extinction of learned fear. Achieving these aims will be significant for two reasons. First, it will contribute to understanding the mechanisms by which animals (including people) learn to adjust their behaviour to bring it into line with the current relations that exist between events in the world. Second, it will provide important information about how such adjustment is facilitated or impaired across extinction training and, thereby, contribute towards understanding both the successes and failures of cue exposure therapy for fear-related disorders.Read moreRead less
The prevalence of asthma in Australia is amongst the highest in the world yet no trials of primary prevention have been conducted which address the most common known causative agent (housedust mite allergens) and the most common known protective factor (dietary omega-3 fatty acids). Until the effectiveness of interventions which address these factors is certain, the value of the wide array of advice given to asthmatics by various health institutions will not be known. We are applying to continue ....The prevalence of asthma in Australia is amongst the highest in the world yet no trials of primary prevention have been conducted which address the most common known causative agent (housedust mite allergens) and the most common known protective factor (dietary omega-3 fatty acids). Until the effectiveness of interventions which address these factors is certain, the value of the wide array of advice given to asthmatics by various health institutions will not be known. We are applying to continue the Childhood Asthma Prevention Study (CAPS) which has been underway since mid-1997. CAPS is a randomised controlled trial in which 616 infants at high risk of developing asthma because of a family history have been enrolled. The interventions include allergen reduction and dietary supplementation with omega-3 fatty acids. The interventions are designed to have maximum effect but be simple to implement by parents. Several measures of compliance are being collected and regular contact is maintained though telephone calls and frequent home visits. Objective and subjective measurements of exposures, atopy, diet and asthmatic symptoms are being collected at 3 month intervals and at medical assessments when the children are 18 months, 3 and 5 years old. It is essential that we continue the study until all children are aged 5 and we will be able to test conclusively whether the interventions have had a positive effect. If so, CAPS will form the basis for a nationwide public health campaign which will have the potential to reduce the incidence of childhood asthma in Australia.Read moreRead less
Increased Vulnerability To Stress During Opiate Dependence: Molecular, Anatomical, And Behavioural Correlates
Funder
National Health and Medical Research Council
Funding Amount
$272,640.00
Summary
Heroin addiction is a major health and societal problem in Australia. It is consistently associated with an adverse impact upon individual users, their families, and communities. It is a chronically relapsing condition for which few, if any effective prevention and treatment strategies exist. Moreover, why an individual initiates and maintains heroin taking remains unclear. Stress and negative emotions have a strong impact on heroin use. Stress may drive some individuals to start using heroin, s ....Heroin addiction is a major health and societal problem in Australia. It is consistently associated with an adverse impact upon individual users, their families, and communities. It is a chronically relapsing condition for which few, if any effective prevention and treatment strategies exist. Moreover, why an individual initiates and maintains heroin taking remains unclear. Stress and negative emotions have a strong impact on heroin use. Stress may drive some individuals to start using heroin, stress increases the pleasurable effects of heroin and stress increases the aversive effects of heroin withdrawal. These effects will encourage addiction and discourage addicts from seeking treatment. Stress can also cause an otherwise drug-free individual to relapse to heroin addiction despite having been drug-free for some time. In this project we will study why stress has such a large impact on heroin addicts and heroin addiction. We will test the hypothesis that heroin use actually produces profound alterations in the neural network in the brain which controls responses to stress. This project uses a simple animal model of heroin addiction whereby rats are injected with morphine to study the regulation of several genes which are important in responding to stress. We will also study how this exposure and changes in gene expression alter neurobiological, cardiovascular, and behavioural responses to stress. This project will identify parts of the brain that are altered during heroin addiction, and will also identify why heroin addicts are more vulnerable to stress than the general population. Therefore, this project will help us to identify targets for therapeutic intervention (both psychological and pharmacological) and possibly disrupt the addictive cycle.Read moreRead less
Environmental Influences On Allergic Airways Disease From Birth To 8yrs: Long-term Outcomes Of A Randomised Trial (CAPS)
Funder
National Health and Medical Research Council
Funding Amount
$530,000.00
Summary
The prevalence of asthma in Australia is among the highest in the world yet no trials of primary prevention have been conducted which address the most common known causative agent (housedust mite allergens) and the most common known protective factor (dietary omega-3 fatty acids). Until the effectiveness of interventions which address these factors is certain, it will not be possible to give confident advice about how to prevent asthma. We are applying to continue follow up of the cohort of the ....The prevalence of asthma in Australia is among the highest in the world yet no trials of primary prevention have been conducted which address the most common known causative agent (housedust mite allergens) and the most common known protective factor (dietary omega-3 fatty acids). Until the effectiveness of interventions which address these factors is certain, it will not be possible to give confident advice about how to prevent asthma. We are applying to continue follow up of the cohort of the Childhood Asthma Prevention Study (CAPS) which has been underway since mid-1997. CAPS is a randomised controlled trial in which 616 infants at high risk of developing asthma because of a family history have been enrolled. The interventions include allergen reduction and dietary supplementation with omega-3 fatty acids. The interventions are designed to have maximum effect but be simple to implement by parents. Objective and subjective measurements of exposures, atopy, diet and asthmatic symptoms are being collected at 3 month intervals and at medical assessments when the children are 18 months, 3 and 5 years old. The interventions are stopped at age 5 years. The continued follow up of the cohort to age 8 will enable us to test conclusively if the interventions have had a positive effect. If so, CAPS will form the basis for a nationwide public health campaign which will have the potential to reduce the incidence of childhood asthma in Australia.Read moreRead less
Exploration Of Exposures Associated With Bedding That Are Risks For Childhood Allergy And Asthma Symptoms
Funder
National Health and Medical Research Council
Funding Amount
$263,500.00
Summary
Asthma prevalence in Australia has doubled in the last 20 years, with 1 in 4 children now affected. House dust mites are probably the single most important allergen associated with asthma. The prevalence of mite allergy is linked to exposure, and such allergy when combined with high exposure, is a potent risk factor for asthma exacerbations. The current international advice for managing mite-allergic asthma, strongly advocates the use of bedding encasings as the best way to reduce exposure. Howe ....Asthma prevalence in Australia has doubled in the last 20 years, with 1 in 4 children now affected. House dust mites are probably the single most important allergen associated with asthma. The prevalence of mite allergy is linked to exposure, and such allergy when combined with high exposure, is a potent risk factor for asthma exacerbations. The current international advice for managing mite-allergic asthma, strongly advocates the use of bedding encasings as the best way to reduce exposure. However, three recent major trials using encasings and a meta-analysis of earlier trials all fail to show a clinical benefit. One of the applicants (ET) recently showed, using expertise in measuring personal exposure, that these encasings, as used, fail to significantly reduce aeroallergen exposure. By contrast, 3 recent Australian studies, involving the applicants, AK, ALP and NG showed that feather bedding compared to synthetic bedding, was strongly protective for asthma - the opposite of public advice. The suggested mechanisms involve reduced exposure to mite allergens, or altered exposure to bacterial endotoxin, but persuasive experimental support is lacking. We also propose a novel hypothesis that feather exposure may induce allergic 'tolerance'. Currently there is a lack of certainty about valid approaches to prevent asthma, and the Global Initiative for Asthma has described the need to understand mechanisms and improve interventions as urgent. This project is an ideal opportunity to combine the expertise of the CIA (ET) in measuring airborne exposures (mite, endotoxin, proteins) with that of the others who have expertise in children's asthma, and who are already involved in two large clinical trails involving different bedding and allergen avoidance. Our measurements of these bedding exposures and their clinical outcomes will provide, for the first time, a quantitative basis to refine public health allergen-based interventions to prevent and manage asthma.Read moreRead less