Assessing the hemodynamic signal sources of fMRI based spontaneous connectivity maps and how neuronal plasticity such as increased spatial working memory can change these networks

Many psychiatric (e.g. schizophrenia) and neurological diseases are characterised by a disturbance of the connections between different parts of the brain that need to communicate with one another. A technique called blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) can determine levels of different activity in parts of the living human brain and how malfunctions can occur in disease. However, this technique has been extended to look at communication between brain regions based on the similarity between ongoing signals (‘brain waves’) in connected parts of the brain. Neuroimaging allows precise information to be gathered about the breakdown of this communication between structures in disease states. However, these magnetic techniques are based on changes in the oxygen content of the blood rather than direct measures of brain activity. They are used because changes in oxygen content can be observed with an MRI scanner without performing surgery on the brain. There is concern, however, because the manifestation of these ongoing brain waves in blood oxygen content is poorly understood and as such the validity of using them to infer communication between brain structures has been questioned. By directly measuring spontaneous brain activity, neuroimaging signals and blood oxygen content at the same time we hope to understand the relationships between them and allow this potentially important aspect of neuroimaging to further our understanding of brain function and its malfunction in disease states.

Research Groups Involved: Dr Myles Jones, Dr Jason Berwick, Dr Aneurin Kennerley, Dr Ying Zheng, Dr CHUANG Kai-Hsiang – Singapore Bioimaging consortium