Dear Jason,
if you already constructed your regressors to enter the design matrix,
you can enter them directly under the 'Regressors' option (instead of
Conditions) - they will be added to the design matrix as is.
Otherwise, you can tweak SPM as you attempted to (it didn't work in your
case because the batch system mistakenly didn't find any basis function
and then put the default, ie canonical HRF). For example, for a NONE
option, edit spm_config_fmri_spec.m:
l.427:
o5 = branch('None','none',{},'');
o5.help = {'None'};
bases = choice('Basis Functions','bases',{hrf,o1,o2,o3,o4,o5},'');
l.750:
if strcmp(fieldnames(job.bases),'hrf')
...
elseif strcmp(fieldnames(job.bases),'none')
SPM.xBF.name = 'NONE';
else
...
and if you have a custom convolution model, you will also have to adapt
spm_get_bf.m
Best regards,
Guillaume.
On 07/09/10 15:19, Jason Steffener wrote:
> Hello all.
> I am interested in either using a custom HRF basis set for an fMRI
> model, or creating my design matrix with a series of regressors that I
> create but then having NO convolution with an HRF model in SPM. I see in
> the code that there is an option for 'NONE' as the basis set. Even if I
> load a job into MatLab and change the bases set to 'NONE' it still
> convolves the model with the default 'HRF' model. I run the job via:
> spm_jobman('run',jobs)
>
>
> My attempt to add custom basis set functionality to SPM was to add a
> case called 'CUSTOM' to the following code:
> spm_config_fmri_design
> spm_config_fmri_spec
>
> and then to add the a "CUSTOM' case to the code:
> spm_get_bf
> I then edited a job and ran it with spm_jobman.This didn't work though.
> It did not even get an error saying that the basis set was unknown.
> Any help on what I am missing would be great.
>
> Thank you,
> Jason.
>
> --
> Jason Steffener, Ph.D.
> Department of Neurology
> Columbia University
> http://www.cumc.columbia.edu/dept/sergievsky/cnd/steffener.html
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
|