3.9 Analyzing Functional and Effective Connectivity with fMRI

Abstract Functional neuroimaging techniques, e.g. positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), and neurophysiological methods, e.g. electroencephalography (EEG) and magnetoencephalograpy (MEG), are used widely in cognitive and clinical neuroscience. A common aim is to understand brain function along two dimensions: functional specialization and functional integration. Functional specialization assumes that AQ1 distinct brain regions are specialized for certain aspects of information processing, but allows for the possibility that this specialization is anatomically segregated across multiple regions. Most current functional neuroimaging experiments have adopted this view and interpret the areas that are activated by a certain task component as the elements of a distributed system. However, this characterization does not address how the locally specialized areas are bound together by context-dependent interactions among these areas, i.e. the functional integration within the system. This chapter reviews established techniques for characterizing functional integration on the basis of functional magnetic resonance imaging (fMRI) data.