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Hi On 12 Apr 2012, at 06:45, Jeroen Siero wrote: > Hi, > > I am using the high pass filter in Feat on my BOLD data (6s ON / 14 s OFF) and I was wondering what kind of filter is implemented? On the feat-log page I can't find the commandline which is used (is it flsmaths using the -pbtf option?) . yes - -bptf the highpass is a subtraction of a Gaussian-weighted running line fit to the data > Also it recommends a filter cutoff off A+r length in seconds, this seems quite strict as it can affect the activation evolution. But then it also depends on what kind of filter is implemented, i.e. what is the filter roll-off. Is there a way to look up what filter is used and how it affects the temporal frequencies using a certain cut-off setting in Feat? For this short paradigm I would stick to something like 60-100s (ie can leave the default), because if you remove too much low frequency then this could affect the robustness of the autocorrlation modelling. Cehers. > > thanks! > > Jeroen Siero > --------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------