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Hi, On 9 Feb 2009, at 21:16, Michael wrote: > Hello, > > I'm using MELODIC for the 1st time. > > Here are my questions: > > 1) Is the resulting time course for each component the average of > all voxels > significantly activated (based on the threshold) in the > corresponding spatial > activation map for that component? Nearly, yes, in effect they are more like the average across voxels _without_ the thresholding applied to the corresponding spatial map - it's not _exactly_ that, but it's close. > 2) are the resulting maps the result of a correlation analysis? Not sure what you're asking.....the maps are the result of ICA (see the MELODIC, McKeown, etc, journal papers), which is not accurately simply summarised as a "correlation analysis", though that is part of it. > 3). what exactly do the negative (blue) cluster of voxels of > activation indicate? In any given component the voxels with negative values have negative correlation with the component's timecourse. Cheers. > > > Your help would greatly be appreciated. > > Michael > --------------------------------------------------------------------------- Stephen M. Smith, Professor of Biomedical Engineering Associate Director, Oxford University FMRIB Centre FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK +44 (0) 1865 222726 (fax 222717) [log in to unmask] http://www.fmrib.ox.ac.uk/~steve ---------------------------------------------------------------------------