Modiwl PPP-4023:
Adv. Neuroimaging Concepts

Overview

1. Neurophysiological basal of the BOLD signal.

2. Functional connectivity. Neuro-physiological correlates of slow BOLD fluctuations and spatial BOLD coherence. Analysis of BOLD coherence: correlation and independent components analysis. Pre-processing issues. Effective connectivity, theoretical underpinnings and analytical limitations. Ethical considerations of the possibility o detect psychiatric diseases due to early changes in connectivity are raised.

3. Structural Imaging. T1 and T2 contrast and the use of multi-spectral imaging for tissue classification. Image data representation, e.g. volumetric vs. surface based. Assessing severity and extension of lesions. Assessing disease processes.

4. Diffusion Tensor Imaging (DTI). Physical principles. Grey and white matter diffusion characteristics. Application of DTI to estimation of Wallerian degeneration, white matter injury, fibre tracking.

5. Perfusion imaging. Overview of non-MR based techniques for estimation of cerebral blood flow. MR perfusion: contrast based vs. non-contrast based estimation of local cerebral blood flood.

6. Spectroscopy. Physical principles. Basic biochemistry of cerebral metabolism. Applications of spectroscopy to the study of metabolic disorders. Principles of analysis and technical limitations.

7. MRI for medical discovery. Establishing MR correlates of disease processes. Voxel Based Morphometry. Multivariate techniques.

8. Ethical implications regarding incidental findings, and possible impact of advanced techniques are introduced and discussed. Discussion will include the ethical implications that arise from the ability to map brain pathways, patterns and metrics of neural connectedness and how these measures may be used in diagnosis, the potential for incidental findings of clinical importance in research participants and how to deal with these findings, and the wider implications of neuroimaging findings and how it may be applied in the wider community.

Learning Outcomes

• 1) Knowledge of imaging relevant aspects of neuroanatomy, neurophysiology and neuropathology. This should include ability to properly name and identify major landmarks on the cortical surface, i.e. sulci and gyri, and subcortical structures and understand their broad functional significance and connectivity. Students should also be able to explain basic concepts pertaining to the transmission of neural impulse and the synaptic organisation in the CNS. The student should also become familiar with how to asses major alteration in brain structure and function due to disease.

• 2) Understanding the physical principles underlying structural, functional and metabolic MRI. This ideas should be supported by a proper appreciation of how a number of other physiological techniques have helped understand the relation between functional signals and neural activity and how physiological modifiers (e.g. hypoxia, hypercarbia, inflammation) may alter the relation between functional signals and neural activity.

• 3) Ability to choose proper analytic tool to determine MR correlates of disease markers.

• 4) Develop an understanding of how imaging protocols and techniques can be used to study a specific cognitive, physiological or disease process. Be able to understand the limitations of functional brain signals and how experimental design need to be tailored to their temporal and spatial characteristics. Understand the ability of different techniques (e.g. block vs rapid event related design, repetition suppression and multivariate approaches) to reveal different aspect of the neural organisation of processes in the human brain.

• 5) Ability to understand and summarise scientific findings reported in the peer-reviewed literature. In particular, how are figures and tables used to illustrate the findings reported by a study. How are statistical test used to support conclusion drawn by the study's authors.

• 6) Critical appraisal of scientific findings. Can the student understand the value of a particular piece of research, its implications for our understanding of brain function. What questions are raised by the study and should be answered? is the interpreatation of the findings in this study crucially dependent on assumptions that have not been fully verified?