Spatial Filter Specifications (Conversion To Mm); Co-Registration Between Data Sets; Fmri Data Analysis - Siemens fMRI User Manual

fMRI User Guide
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3.2.11 Spatial Filter specifications (conversion to mm)

From the BOLD Apps Brochure: Filter strength: A Gauss filter is used for image filtration. Smaller filter values effect
a stronger limitation of high signal values and therefore a stronger filtration.
Filter value
2
1.0
0.5
From ICE programming manual:
<Label> "Filter Setting"
<Precision> 1
<LimitRange> {0.1 5.0}
// "Filter parameter for the 3D spatial filter. Please enter the value below (value must be > 0)."
// "Meaning: The filter window has reached zero for 'value'-times of the Nyquist frequency."
// "eff. resulting voxelsize is approx. = voxelsize * sqrt( 1+4/(value^2) )"
// "Note: smaller value = stronger filter."
<Default> 1.0
So, for 2 mm isotropic voxels, a fiter setting of 2 (weak) gives a resulting approximate voxel size of 2*sqrt( 1+4/
(1^2) ) = 2.8 mm isotropic. Average (1.0) gives 4.4 mm, strong (0.5) gives 8.2 mm.

3.2.12 Co-registration between data sets

There is no co-registration done in the Neuro3D taskcard. The recommendation is to use AutoAlign during data
measurement. This will automatically place all the data sets in the same reference frame.

3.3 fMRI Data analysis

For details on how to analyze the BOLD data, please refer to the BOLD Imaging Application brochure.
Effect
weak
average
strong