Projects
Available Masters and PhD Projects - 2011
Executive control of attentional networks across the lifespan: implications for neuropsychiatric and addictive disorders
Over the past decade, The Melbourne Neuropsychiatry Centre has used the Multi-Source Interference Task (MSIT) in several functional MRI (fMRI) studies to examine brain networks underlying attentional control in healthy controls and clinical patients. We have now collected nearly 300 healthy controls (age range 16-55 years) and 300 clinical patients (with schizophrenia, bipolar disorder, depression, obsessive-compulsive disorder, as well as cannabis and opiate dependence).
By virtue of its strong demands on attentional and inhibitory response control, this task also consistently engages other frontal, cingulate, parietal and cerebellar regions. Many of these brain regions have been found to be undergoing developmental changes from early adolescence through to late adulthood. These same regions have also been implicated in a variety of neuropsychiatric and addictive disorders.
A major challenge is that this data has been acquired across 3 different scanners and 2 different field strengths (i.e., 1.5T Siemens, 3.0T Siemens, 3.0T GE) and slightly different parameters (e.g., TR, TE, number of slices, number of volumes). The role of the PhD candidate will be to integrate this data in a way that enables analysis of the full dataset. Once this is achieved, the PhD candidate will then have rich and complex database and have the opportunity to ask many questions about normal and abnormal development and functioning of the brain networks underlying attentional control in healthy and clinical populations. Specifically, the current PhD will address the following issues:
- GENERAL OBJECTIVES
- What is the best method(s) to combine data from multiple scanners, field strengths and parameters into one comparable dataset?
- What are the key age-related characteristics of the attentional control networks?
- How does demographic and background variables influence the findings? For example, are males are more likely to have certain patterns of network characteristics? How do other demographic, and mental health variables (e.g., anxiety, depression) influence the manifestation of these patterns of brain activity?
- Can statistical techniques such as via factor, cluster, ICA, and discriminant analysis be used to define functional/neurobiological phenotypes that are informative and independent of diagnostic labels?
- What is the degree of comorbidity across neuropsychiatric and addictive disorders can be explained? Does one functional network disturbance lead to an increased vulnerability for other disturbances? Does this suggest shared vulnerability?
- How might dopamine and genetic variables influence the findings (future implications) ? For example, striatal dopamine and genetic variations (e.g., SLC6A3) have been found to influence activation patterns. How does this fit with predicting, characterising illness specific versus general factors?
A/Prof Murat Yücel will primarily supervise the candidate, while Dr Ben Harrison will co-supervise. Prof Christos Pantelis, A/Prof Stephen Wood and Mr. George Youssef will also be involved in the project. The candidate will be required work across multiple research organizations across the University of Melbourne (i.e., Melbourne Neuropsychiatry Centre and Orygen Youth Health Research Centre).
Supervisors: Assoc Prof Murat Yücel, Dr Ben Harrison
Location: Melbourne Neuropsychiatry Centre, National Neuroscience Facility (NNF),
Alan Gilbert Building, Level 3, 161 Barry Street, Carlton South, Vic 3053
Orygen Youth Health Research Centre, 35 Poplar Road, Parkville 3052
Contact: Assoc Prof Murat Yücel E:muratATunimelb.edu.au T: 8344 1877
Dr Ben Harrison E: habjATunimelb.edu.au
Impulsive-Compulsive Behaviours in Parkinson’s Disease following Dopamine Agonist Therapy
Growing evidence suggests that ICBs are significantly more prevalent in patients with Parkinson’s disease who are receiving dopamine agonist treatment. Specifically, dopaminergic medication-related disorders such as pathological gambling, hyper-sexuality, and to a minor extent over-eating and shopping have been reported in Parkinson’s disease. While such treatments may have significant implications for the affected individual, the issue has not been comprehensively investigated. One major hurdle has been the clear lack of instruments to measure and characterize ICBs. We have now developed a testing battery that is able index inter-individual variations to ICBs (see Methods for details). The role of the PhD candidate will be to apply this battery of tests and conduct neuroimaging to investigate the neural and psychological bases of these ICBs in patients with Parkinson’s disease undergoing dopamine therapy. These measured would be acquired several times through the different stages of illness and therapy. The findings will likely have implications for understanding the fundamental neurobiology of ICBs, as well as clinical implications (i.e., help predict vulnerable individuals most at-risk of going on to develop ICBs). The PhD candidate will address the following:
- GENERAL OBJECTIVES
- Does dopaminergic treatment in Parkinson’s disease lead to an increased prevalence of Impulse Control Disorders (ICDs)? Is there a greater prevalence of ICBs that are not case-level?
- Is this association the same for all dopamine treatments (e.g., l-dopa versus other dopamine agonists)? Is the association dose-dependent? Does the severity decrease when treatment is ceased? What role do drugs of abuse (also dopamine agonists) play in this association?
- Can we prospectively predict ICBs in Parkinson’s disease using brain imaging, cognitive and affective neuroscience techniques?
- Does a family history of ICBs and ICDs lead to an increased vulnerability? Are these direct vulnerabilities (i.e., family history of problem gambling leads to a vulnerability to the same) or more diffuse (i.e., family history of problem gambling leads to a vulnerability to other ICBs?
- Are ICBs dependent on socio-cultural factors? For example, are males are more likely to develop gambling and sexual problems while females develop eating and buying disorders?
- How do other demographic (e.g., age), and mental health variables (e.g., anxiety, depression) influence the manifestation of ICBs?
- How do other stereotypes behaviours such as punding and compulsive behaviours such as dopamine dependency syndrome for into the picture of ICBs?
- Interrogation of retrospective clinical notes/assessments
- determine incidence of ICBs
- determine incidence of co-morbidities and confounds (eg., anxiety/mood, Family History Personal History of ICBs, form of DA use [fast or slow acting agonists], [DDS, DA++ vs L-Dopa])
- select groups to study (case level and/or spectrum)
- Prospective Assessment of a large series of cases (anxiety/mood, motivation, state/trait, neurocog, FH, other confounds)
- Conduct a fMRI/MRS study (task, resting and MRS of dorsal versus ventral striatum to test ICB models)
- Write-up as Case-Studies (unique cases or a series of n=1 cases)
A/Prof Murat Yücel will be the primary supervisor, while Dr Andrew Evans will co-supervise. The scientific and clinical directors, Prof Christos Pantelis and Dr Dennis Velakoulis will also be involved. The candidate will be based at the Melbourne Neuropsychiatry Centre.
Supervisors: Assoc Prof Murat Yücel, Dr Andrew Evans
Location: Melbourne Neuropsychiatry Centre, National Neuroscience Facility (NNF),
Alan Gilbert Building, Level 3, 161 Barry Street, Carlton South, Vic 3053
Contact: Assoc Prof Murat Yücel E:muratATunimelb.edu.au T: 8344 1877
Impulsive-Compulsive Behaviours in Severe Obesity: Prospective predictors or treatment success/failure following LAP-BAND surgery
Growing evidence suggests that ICBs are significantly more prevalent in patients with eating disorders, including severe obesity. While such difficulties may have significant implications for the affected individual (e.g., maintaining maladaptive eating behaviours, and leading to an a reduced capacity to take advantage of external resources such as educational opportunities and treatment options), the issue has not been comprehensively investigated. One major hurdle has been the clear lack of instruments to measure and characterize ICBs. We have now developed a testing battery that is able index inter-individual variations to ICBs. The role of the PhD candidate will be to apply this battery of tests to investigate the neural and psychological bases of these ICBs in patients with obesity about to undergo LAP-BAND (adjustable gastric band) surgery. The findings are likely to have translational implications in helping to identify optimal patients for LAP-BAND surgery, for psychological interventions targeting self-control, and to set more realistic goals in therapies. This knowledge will also be used to create more homogenous cohorts of obese individuals with “pure” impulsive or compulsive or “mixed” behavioural problems and facilitate the study of its fundamental neurobiology (via fMRI and genetic studies), as well as have implications for diagnosis and treatment (e.g., the discovery of crossover pharmacotherapies). Specifically, the PhD candidate will address the following questions:
- GENERAL OBJECTIVES
- Do obese patients about to undergo LAP-BAND surgery have problems with impulsivity and compulsivity (using state [neurocognitive] and trait [temperament/personality] measures)?
- How common are ICBs such as excessive internet usage, gambling, substance abuse in obese individuals undergoing LAP-BAND surgery? Is there a shared vulnerability?
- Does LAP-BAND surgery lead to changes in impulsivity, compulsivity or ICBs?
- Can we prospectively predict which individuals: (i) will respond best (or worst) to; and (ii) be most (or least) compliant with LAP-BAND surgery at 12-24 month follow-up using brain imaging, cognitive and affective neuroscience techniques?
A/Prof Murat Yücel will be the primary supervisor, while Dr Melissa Hayden will co-supervise. A/Prof Wendy Brown and Dr Manjula O’Connor will also be involved in supervision. The candidate will be based across the Melbourne Neuropsychiatry Centre (MNC), and the Centre for Obesity Research and Education (CORE).
Supervisors: Assoc Prof Murat Yücel, Dr Melissa Hayden
Location: Melbourne Neuropsychiatry Centre, National Neuroscience Facility (NNF),
Alan Gilbert Building, Level 3, 161 Barry Street, Carlton South, Vic 3053
Centre for Obesity Research and Education
Contact: Assoc Prof Murat Yücel E:muratATunimelb.edu.au T: 8344 1877
Predictors of Impulsive-Compulsive Behaviours during Adolescence
It is well known that “compulsive” and “impulsive” behaviours relate to a host of personal and social problems (e.g., excessive eating and internet useage, pathological gambling etc), which are commonly observed in the general population. Despite the prevalence of these problematic behaviours, very little is known about how individual differences in the psychological and biological aspect of self-regulation influence impulsive and compulsive behaviours (ICBs), and lead to a vulnerability to mental health problems. The role of the PhD candidate will be to apply this battery of tests (see Methods for details) to investigate the neural and psychological bases of these ICBs in a healthy population of nearly 200 adolescents (now aged 18-19 years) that we have been following since late childhood (since age 12-13 years) as a part of a Adolescent Development Study (ADS) in Melbourne. Once the current level of ICBs have been characterized in these adolescents, the candidate will be given access to the wealth of brain imaging, as well as cognitive-affective, neuropsychological, psychophysiological, and genetic data that has been collected from these same individuals over the past 6 years. This will provide a rich prospective dataset to investigate how brain networks and cognitive-affective processes mature through the life-span and how disruptions to them or genetic polymorphisms can lead to the maladaptive ICBs. This knowledge will then be used to create more homogenous cohorts with “pure” impulsive or compulsive behavioural problems or “mixed” groups to facilitate the study of its fundamental neurobiology (via fMRI and genetic studies), as well as having implications for the diagnosis and treatment of behavioural problems and associated disorders. Specifically, the PhD candidate will address the following questions:
- GENERAL OBJECTIVES
- What are the psychological, motivational, and neurocognitive underpinnings of ICBs?
- What is the degree of comorbidity across ICBs? Does one ICB lead to an increased vulnerability for other ICBs? Does this suggest shared vulnerability?
- How do other demographic (e.g., age, gender), and mental health variables (e.g., anxiety, depression) influence the manifestation of ICBs?
- Can statistical techniques such as via factor, cluster, and discriminant analysis be used to define behavioural phenotypes (impulsive versus compulsive versus mixed)?
- Can brain imaging be used to define neurobiological phenotypes?
- Can we predict individuals at-risk for developing ICBs using brain imaging, cognitive and affective neuroscience techniques?
- Conduct ICB screener on ALL participants (~150) (short & at home/internet)
- determine incidence of ICBs
- determine incidence of co-morbidities among various ICBs
- select ICB groups to study (case level and/or spectrum)
- Conduct more detailed follow-up assessment of ICBs in a smaller subgroup (~100) (motivation, state/trait, neurocog, other)
- Look at T1-T3 data to predict ICBs prospectively (sMRI, fMRI [rest/msit], Npsych, PPhysi, other)
- Conduct fMRI study in small ICB subgroups (~50) (task & resting of dorsal vs ventral striatum to test ICB models)
A/Prof Murat Yücel will primarily supervise the candidate, while Prof Nick Allen will co-supervise. Dr Sarah Whittle and Dr Ben Harrison will also be involved. The candidate will be required work across multiple research organizations across the University of Melbourne (i.e., Melbourne Neuropsychiatry Centre and Orygen Youth Health Research Centre).
Supervisors: Assoc Prof Murat Yücel, Prof Nick Allen
Location: Melbourne Neuropsychiatry Centre, National Neuroscience Facility (NNF),
Alan Gilbert Building, Level 3, 161 Barry Street, Carlton South, Vic 3053
Orygen Youth Health Research Centre, 35 Poplar Road, Parkville 3052
Contact: Assoc Prof Murat Yücel E:muratATunimelb.edu.au T: 8344 1877
To enquire about current available student projects please send an email