:: Functional Neuroimaging & Neuroinformatics ::

Supervisors:
Dr David Abbott         Email: d.abbott (at brain.org.au)

Project 1: Exploration of functional synchrony in brain networks using MRI: Functional MRI (fMRI) has been used since the early 1990’s to image the brain’s response to specific stimuli. It is an MRI technique that makes use of an intrinsic contrast mechanism involving the different magnetic states of oxygenated and de-oxygenated haemoglobin. Recently it has been found that the blood-oxygenation level dependant (BOLD) fMRI signal measured whilst a subject is at “rest” contains low frequency (<0.1Hz) fluctuations that appear to be related to functionally connected networks. This project involves development of novel image analysis strategies to maximise information extracted from resting state fMRI time series, and to help determine how these techniques can best be applied to improve our understanding of brain networks in the healthy and diseased brain.

Project 2: The generators of epilepsy in the human brain: Combined functional magnetic resonance imaging (fMRI) and electro-encephalography (EEG) approaches will be used to define the brain networks in patients with epilepsy. The aim of this project is to identify the components of the network that are responsible for the generation of the hypersychronisation that is characteristic of the epileptic seizure.  This project uses advanced neuroimaging methods in functional imaging including functional connectivity and independent component analysis.

Project 3: Study of the effects of seizures on language organization in humans: This project will characterise language brain organization before and after surgery in a group of patients with epilepsy, as well as determine how seizures may interfere with this brain function.

Project 4: Direct detection of neuronal currents with MRI: Functional MRI (fMRI) utilizing blood oxygenation level dependent (BOLD) contrast has become one of the most widely used methods for the non-invasive mapping of neuronal activity in the human brain. It is however an indirect technique, measuring changes in the vasculature rather than neuronal activity directly. The response of the vasculature is much slower than the underlying neuronal activity, thus limiting the temporal resolution of fMRI. The spatial extent of fMRI activation is also generally somewhat larger than the presumed localized zone of firing neurons responsible for the change in blood flow. Over the last few years we have developed an MRI technique which could potentially be used to directly detect localised magnetic effects arising from neuronal currents. This could provide a neuronal mapping method with millimetre spatial resolution and millisecond timing resolution. Our preliminary results are encouraging, however there is much work still to be done to characterise and further develop the method.

Project 5: Optimisation of functional imaging acquisition and analysis: Functional MRI (fMRI) is now so widely accepted as a research tool to help map and understand the functional behaviour of the human brain, that it is easy to forget that the first human fMRI studies were conducted just fifteen years ago. There are now thousands of published fMRI studies mapping human brain function in health and disease, most driven by clinician neuroscientists successfully applying what are now considered established methods of acquisition and statistical analysis. Too often, however, the methods used are not optimal, nor even appropriate. Recent research in our own laboratory and in others indicates that there is a wealth of information that can be extracted from existing fMRI studies that is currently being ignored. The aim of this project is to systematically investigate a selection of current MRI analysis controversies, develop and evaluate several novel methods of analysis, and investigate brain function and structure using the existing imaging data of healthy individuals and patients.

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