The brain is a complex system of cellular networks and communication pathways, whose structure and function are regulated by a vast number of genes and gene products (i.e. proteins). Despite rapid advances in genomic and proteomic technologies in the past decade, the specific functions of most genes expressed in the brain, and the proteins for which they encode, are largely unknown. Therefore, the problem of determining the underlying causes of debilitating brain disorders, such as depression, schizophrenia and drug addiction, which are strongly influenced by environmental as well as genetic factors, is a very challenging one. Recent human imaging studies have used sophisticated analysis methods to reveal subtle changes in the structure and connectivity of brain regions in subjects with early onset schizophrenia. While these results are intriguing and may be used in the future as biomarkers for detecting early signs of disease, they do not shed much light on the underlying molecular mechanisms that lead to these changes. These mechanisms need to be understood in order to identify potential molecular targets for new drugs that may be able to treat the disease.
This presentation will focus on the role of positron emission tomography (PET) and related molecular imaging techniques in tackling this complex problem. The recent convergence of genomic and imaging technologies will be reviewed, together with recent advances that have led to the widespread application of molecular imaging studies in animal models of brain disorders. For example, we have developed methods to image molecular brain function using PET in awake, freely moving rats while simultaneously observing behavioural changes due to environmental stimulus. The current status of this research will be presented, along with future challenges and prospects for exploring the interactions between genetic, molecular and environmental factors underlying brain function in health and disease.
Steven Meikle is Professor of Medical Imaging Physics and Head of the Imaging Physics Laboratory at the Brain and Mind Research Institute (BMRI). He received his Bachelor of Applied Physics degree from the University of Technology, Sydney in 1988 and his Ph.D. degree from the Graduate School of Biomedical Engineering, University of New South Wales in 1995. He was a medical physicist at Royal Prince Alfred Hospital in Sydney (1987-2004), a visiting research associate at the Division of Nuclear Medicine and Biophysics, UCLA School of Medicine in Los Angeles (1991-2) and a post doctoral research scientist at the MRC Cyclotron Unit, Hammersmith Hospital in London (1995-6) before joining the University of Sydney in 2004. Steven has published 7 book chapters and 166 research papers which have been cited more than 3,000 times in the scientific literature. He is a Fellow of the Australian Institute of Physics, a Senior Member of the IEEE and a Visiting Professorial Fellow at the Centre for Medical Radiation Physics at the University of Wollongong. He serves on the Editorial Board of the journal Physics in Medicine and Biology, the Governing Board of the NCRIS National Imaging Facility, the ANSTO Life Sciences Advisory Committee and is Co-Director of the Ramaciotti Imaging Centre at the BMRI. He received the Horvath Energy International Prize in 1986, the Australian Institute of Physics Award in 1987, the University Medal from the University of Technology, Sydney in 1988, the Boyce Worthley Prize for distinction in the practice of physical and engineering sciences in medicine from the ACPSEM in 1994 and the Siemens Preclinical Image of the Year Award in 2009.