Dear Matt,
If your custom HRF can still be parametrised as the difference of two
Gamma functions then you can just change the default values
'stats.fmri.hrf', see spm_hrf.m.
Otherwise the function constructing the design matrix is
spm_fMRI_design.m, which starts by calling spm_get_bf.m. You would have
to modify this last function to return your custom HRF at the requested
sampling rate.
Best regards,
Guillaume.
On 16/12/2018 15:40, Heard, Matt wrote:
> Hello SPM users,
>
>
> I am trying to create a Matlab script that will construct a first-level
> GLM, just like SPM, but using a custom hemodynamic response function
> (HRF) for convolution. My questions are as follow:
>
>
> 1) Rather than write an entire script to create the GLM matrix, are
> there any options using SPM GUI to import your own custom HRF function?
>
> 2) My understanding is that creating a GLM includes the following steps:
> (a) introducing a high-pass filter to detrend data, (b) address
> autocorrelation within the data, and (c) convolve functional data with
> the HRF. Am I missing any steps?
>
> 3) For the above steps, is there a correct order to execution?
>
>
> Thanks so much,
>
>
> Matthew Heard
> Graduate Student
> *The Ohio State University*
> Arts and Sciences Neuroscience Graduate Program
> 004 Pressey Hall, 1070 Carmack Road, Columbus, OH 43201
> 214-458-7255 Mobile
> [log in to unmask] <mailto:[log in to unmask]>
> <http://osu.edu>https://osu-slam.github.io/
>
> /Buckeyes consider the environment before printing./
>
>
--
Guillaume Flandin, PhD
Wellcome Centre for Human Neuroimaging
UCL Queen Square Institute of Neurology
London WC1N 3BG
|