Understanding The Role Of Sex Hormones In Mental Illness
Funder
National Health and Medical Research Council
Funding Amount
$419,180.00
Summary
Evidence suggests that the female hormone, estrogen, protects against schizophrenia, although the exact mechanism of action underlying this effect is unclear. We believe that by measuring estrogen-induced changes in the levels of genes in the brain, we will identify the way that estrogens protect against the symptoms of schizophrenia and improve antipsychotic treatment response.
Standardisation Of Prepulse Inhibition Of The Startle Reflex For Pharmacological And Interspecies Comparisons
Funder
National Health and Medical Research Council
Funding Amount
$252,761.00
Summary
People and other animals startle when they here a sudden loud sound. How much one startles depends in part on how loud the sound is. The relationship between the loudness of the sound and the size of the startle resembles a ski slope. Each individual has a ski slope that differs from others; the beginning of the ski slope (threshold) occurs at a different loudness, the slope is a different steepness, and the height of the ski slope where the plateau occurs is different. There are genetic differe ....People and other animals startle when they here a sudden loud sound. How much one startles depends in part on how loud the sound is. The relationship between the loudness of the sound and the size of the startle resembles a ski slope. Each individual has a ski slope that differs from others; the beginning of the ski slope (threshold) occurs at a different loudness, the slope is a different steepness, and the height of the ski slope where the plateau occurs is different. There are genetic differences in ski slopes as well. The size of the startle reflex can also be reduced by preceding the startling sound with a quiet stimulus a few tens of milliseconds before the startling stimulus. This is known as prepulse inhibition of the startle reflex or PPI for short. There is much interest in PPI, because it differs in people with certain mental illnesses, such as schizophrenia or post-traumatic stress disorder, and certain neurological illnesses, such as Huntington's chorea. It is also affected by drugs, including stimulants, stress hormones, and cannabis. In almost all the hundreds of experiments on PPI the effect of the prepulse on the response to a startling stimulus is measured at only one startling stimulus loudness. This loudness can be at very different parts of the ski slope for different people or other animals: it may be in the steep slope for one person, well into the plateau for another, or even at the bottom of the ski slope below the threshold in others. The effect of PPI is very different depending on what part of the ski slope the loudness represents. A lack of consistent effects in the literature on PPI by drugs and genetics is explained by this difference. Experiments are planned that will investigate the effect of drugs that are similar to those that treat schizophrenia, stress hormones and cannabis on the effect of prepulses on the whole ski slope. This procedure will provide the consistency in results so far absent.Read moreRead less
Functional Neuroimaging Of Prepulse Inhibition In Schizophrenia And Parkinson's Disease
Funder
National Health and Medical Research Council
Funding Amount
$446,750.00
Summary
Inhibition deficits have been consistently demonstrated in a broad spectrum of neuropsychiatric conditions that have been implicated with altered neurotransmitter function of the brain. These conditions include mental disorders like schizophrenia, obsessive-compulsive disorder, and pathological gambling and neurological disorders like Huntington's disease, Gilles-de-la-Tourette syndrome and other conditions which are characterised by impaired impulse control. Studies on animal models suggest tha ....Inhibition deficits have been consistently demonstrated in a broad spectrum of neuropsychiatric conditions that have been implicated with altered neurotransmitter function of the brain. These conditions include mental disorders like schizophrenia, obsessive-compulsive disorder, and pathological gambling and neurological disorders like Huntington's disease, Gilles-de-la-Tourette syndrome and other conditions which are characterised by impaired impulse control. Studies on animal models suggest that an impaired dopamine neurotransmission - either genetically pre-determined and-or stress-induced by environmental factors - may significantly contribute to a common pathological mechanism across these conditions that, in turn, results in impaired 'sensory motor gating', a physiological measure of inhibitory brain processes. Traditionally, sensory motor gating is indirectly measured using the acoustic startle eye-blink response. However, this peripheral measure cannot directly assess the brain processes underlying sensory motor gating. This study will apply new functional brain imaging methodology and EEG-based source localisation techniques to assess the neural substrates of inhibitory processes involved in sensory motor gating in two neuropsychiatric conditions that involve dysfunctional dopaminergic mechanisms: schizophrenia and Parkinson's disease.Read moreRead less
Interaction Of Oestrogen With The Serotonin-1A Receptor: Implications For Schizophrenia
Funder
National Health and Medical Research Council
Funding Amount
$229,744.00
Summary
Gender differences have been observed in mental illnesses such as schizophrenia. It has been suggested that the female sex hormone, oestrogen, protects against schizophrenia, although how this occurs is unclear. This project aims to understand the mechanisms by which oestrogen interacts in the brain with major chemical systems (including serotonin and dopamine) that are implicated in the development and symptoms of schizophrenia.
Attentional Effects On Prepulse Inhibition Of The Acoustic Startle Reflex In Patients With Schizophrenia
Funder
National Health and Medical Research Council
Funding Amount
$278,625.00
Summary
People suffering from schizophrenia exhibit differences from healthy people in the startle reflex, which is a blink of the eyes when a sudden loud sound occurs. Normally, this reflex is reduced in size when a quiet sound occurs a few milliseconds before the startling sound, but this prepulse inhibition of the startle reflex or PPI does not occur to the same degree in people with schizophrenia. The underlying causes of this reduction in PPI in patients with schizophrenia is not known. The most co ....People suffering from schizophrenia exhibit differences from healthy people in the startle reflex, which is a blink of the eyes when a sudden loud sound occurs. Normally, this reflex is reduced in size when a quiet sound occurs a few milliseconds before the startling sound, but this prepulse inhibition of the startle reflex or PPI does not occur to the same degree in people with schizophrenia. The underlying causes of this reduction in PPI in patients with schizophrenia is not known. The most commonly accepted theory is that it reflects a deficit in a basic sensorimotor gating function which could underlie a variety of attentional abnormalities observed in schizophrenia. However, our data indicate that patients exhibit more PPI when they ignore the prepulse stimuli. We wish to test the hypothesis that alterations in PPI in schizophrenic patients are secondary to abnormalities in attention. This is significant because the theory can point to a specific cognitive deficit associated with schizophrenia. We have also found that patients treated with some kinds of antipsychotic medications (the newer atypical antipsychotic medications) do not show reductions in PPI, but patients treated with older types of antipsychotic drug do show reductions in PPI. We intend to investigate the effects of different types of antipsychotics on attentional modulation of PPI. This is significant because it may indicate that patients with a specific kind of cognitive impairment may show improvement with a specific type of medicine. Our data suggests that chronic cannabis use may associated with differences in the startle reflex and in PPI. Understanding how such cannabis use alters PPI may provide insights into why so many people with schizophrenia regularly abuse cannabis.Read moreRead less
Methods To Improve Detail Reproduction Of Elastic Impression Materials
Funder
National Health and Medical Research Council
Funding Amount
$96,656.00
Summary
If a dental prosthesis is to fit precisely in the mouth, an accurate impression must be taken of the teeth and surrounding tissues. This research aims to evaluate variable surface conditions which may be taken into consideration to achieve an accurate impression, such as moisture, temperature, and the presence of contaminants. Although any distortions as a result of material interactions would be limited to the surface interface, inaccuracies here may ultimately compromise treatment success.
Schizophrenia is classified among the world’s top ten enduring disabilities. Hearing voices are a profound and distressing symptom, which have proven difficult to successfully treat. We plan to use the latest brain imaging techniques and genetic testing to develop the most comprehensive understanding of hearing for voices to date. These data are vital to the development of novel tailored treatment for patients who hear voices.
Study Of Motor Inhibition Deficits In Schizophrenia Using MRI, EventRelatedPotentialsand Transcranial Magnetic Stimulation
Funder
National Health and Medical Research Council
Funding Amount
$261,687.00
Summary
The aim of the proposed project is to study the neural mechanism underlying failures of motor-inhibition in patients with schizophrenia. The project will involve the use of fMRI and ERP measures during performance of a Stop-Signal Task, in order to explore the neural substrates of task performance in healthy subjects, and activational differences in schizophrenia patients. In a separate experimental session TMS will be applied in order to disrupt neural processing at cortical sites identified by ....The aim of the proposed project is to study the neural mechanism underlying failures of motor-inhibition in patients with schizophrenia. The project will involve the use of fMRI and ERP measures during performance of a Stop-Signal Task, in order to explore the neural substrates of task performance in healthy subjects, and activational differences in schizophrenia patients. In a separate experimental session TMS will be applied in order to disrupt neural processing at cortical sites identified by fMRI. Systematic use of TMS across different cortical sites will be used to compare effects of cortical site and subject group on task performance.Read moreRead less