Thank you so much Doug! I just have one more question: Before convolving regressors with HRF, I looked at X matrix and noticed that the values of regressors have been changed/scaled. For example, the original values in a regressor file are:
134.8300 0 141.1200 0 91.5310 0 96.1870 0 But they have been apparently shifted by a constant value in the X matrix: 91.8168 -43.0132 98.1068 -43.0132 48.5178 -43.0132 53.1738 -43.0132 Why is there such a change in the regressor values? Thanks, Reza You can use the following matlab code. You can ignore the warning printed after the toepliz operation. The OriginalRegressor should be a vector of length Ntp, then write out the NewRegressor to a new external regressor file. TR=2; % seconds Ntp=100; t = TR*[0:Ntp-1]'; h = fast_spmhrf(t); a = zeros(Ntp,1); a(1) = 1; X = toeplitz(h,a); NewRegressor = X*OriginalRegressor; On 02/21/2017 04:02 PM, Reza Rajimehr wrote: >* Hi Doug, *>>* Since our external regressors are stimulus-related (e.g. mean *>* luminance of stimuli), we need to convolve them with a hemodynamic *>* response function. In mkanalysis-sess, we have used -spmhrf 0 to model *>* conditions. Is there a code or Matlab script for HRF convolution, so *>* that we apply exactly the same spmhrf function for modeling the *>* external regressors? *>>* Thanks, *>* Reza *>>* No, they are not *>>>* On 02/17/2017 05:09 PM, Reza Rajimehr wrote: *>* >/During the functional analysis in FS-FAST, are the external regressors />/convolved with the hemodynamic response function? />//>/Thanks, />/Reza />//>//>/_______________________________________________ />/Freesurfer mailing list />/Freesurfer at nmr.mgh.harvard.edu <http://nmr.mgh.harvard.edu> *>* <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer>> />/https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> / *>* -- *>* Douglas N. Greve, Ph.D. *>* MGH-NMR Center *>* greve at nmr.mgh.harvard.edu <http://nmr.mgh.harvard.edu> *>* <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer>> *>* Phone Number: 617-724-2358 *>* Fax: 617-726-7422 *>>* Bugs:surfer.nmr.mgh.harvard.edu/fswiki/BugReporting <http://surfer.nmr.mgh.harvard.edu/fswiki/BugReporting> *>* <http://surfer.nmr.mgh.harvard.edu/fswiki/BugReporting <http://surfer.nmr.mgh.harvard.edu/fswiki/BugReporting>> *>* FileDrop:https://gate.nmr.mgh.harvard.edu/filedrop2 <https://gate.nmr.mgh.harvard.edu/filedrop2> *>* www.nmr.mgh.harvard.edu/facility/filedrop/index.html <http://www.nmr.mgh.harvard.edu/facility/filedrop/index.html> *>* <http://www.nmr.mgh.harvard.edu/facility/filedrop/index.html <http://www.nmr.mgh.harvard.edu/facility/filedrop/index.html>> *>* Outgoing:ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/ <ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/> *>>>* _______________________________________________ *>* Freesurfer mailing list *>* Freesurfer at nmr.mgh.harvard.edu <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> *>* https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> * -- Douglas N. Greve, Ph.D. MGH-NMR Centergreve at nmr.mgh.harvard.edu <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: https://gate.nmr.mgh.harvard.edu/filedrop2www.nmr.mgh.harvard.edu/facility/filedrop/index.html Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/
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