Hi - I don't know you - you'll need to ask the fslstat people - but I
suspect it may be like the "Sine" option in FEAT.
Cheers.
On 9 Sep 2009, at 00:07, Yoon Han wrote:
> Dear FSL experts,
>
> I'm currently trying to replicate the findings with FMRILM (of
> FMRIstat package) using FEAT. The command in question is:
>
> [df, spatialav] = fmrilm(infname, [repmat('stats/', ncontrasts,
> 1) ...
> strvcat(contrastnames)], xcache, contrasts, exclude,
> whichstats, fwhmcor, ntrends, confounds)
>
> in fmrilm.m, usage is shown as
> % [DF, SPATIAL_AV] =
> % FMRILM( INPUT_FILE, OUTPUT_FILE_BASE, X_CACHE, CONTRAST
> % [, EXCLUDE [, WHICH_STATS [, FWHM_COR [, N_TRENDS [, CONFOUNDS
> % [, CONTRAST_IS_DELAY [,NUM_HRF_BASES [, BASIS_TYPE [,NUMLAGS
> % [, DF_LIMIT ]]]]]]]]]] )
> % NUM_HRF_BASES is a row vector indicating the number of basis
> functions
> % for the hrf for each response, either 1 or 2 at the moment. At least
> % one basis functions is needed to estimate the magnitude, but two
> basis
> % functions are needed to estimate the delay. If empty (default), then
> % NUM_HRF_BASES is 2 for each response where CONTRAST is non-zero and
> % _del appears in WHICH_STATS, otherwise NUM_HRF_BASES = 1. By setting
> % NUM_HRF_BASES = 2 you can allow for an unknown delay, without
> % actually estimating it. Example:
> % CONTRAST=[1 -1 0 0; 1 0 -1 0]; WHICH_STATS=['_mag_t'; '_del_t']
> % The first contrast is the magnitude of response_1 - response_2;
> % the second contrast is the delay of response_1 - response_3.
> % The default setting of NUM_HRF_BASES is [2 1 2 1]. By setting
> % NUM_HRF_BASES=[2 2 2 1] unknown delays are allowed for the second
> % response but not actually estimated.
> %
> % BASIS_TYPE selects the basis functions for the hrf used for delay
> % estimation, or whenever NUM_HRF_BASES = 2. These are convolved with
> % the stimulus to give the responses in Dim 3 of X_CACHE.X:
> % 'taylor' - use hrf and its first derivative (components 1 and 2), or
> % 'spectral' - use first two spectral bases (components 3 and 4 of
> Dim 3).
> % Ignored if NUM_HRF_BASES = 1, in which case it always uses
> component 1,
> % i.e. the hrf is convolved with the stimulus. Default is 'spectral'.
>
> What i'm particularly confused is the num_hrf_bases and basis_type.
> Since my command didn't specify the basis_type, the basis_type is
> 'spectral' using FMRIstat package. Which convolution in FEAT is this
> equivalent to? Thank you for your help.
>
> Yoon Han
>
---------------------------------------------------------------------------
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
---------------------------------------------------------------------------
