Dear Sungho,

Thanks for your quick response.
I have tried the updates codes that you gave me but still, have the same problem after trying to upload "multiple_conditions.mat" file.
Also, I tried to follow the steps for entering the experimental design instead of using "multiple_conditions.mat" and I got this error:

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Specify GLM-fNIRS for the 1st level analysis...
---------------------------------------------------------
Hemoglobin signal to be analysed: HbOHbR

Specify experimental design...
Reference to non-existent field 'K'.
Error in spm_fnirs_specify1st_ui (line 115)
Error in spm_fnirs>push_specify_Callback (line 75)
function push_specify_Callback(hObject, eventdata, handles)
Error in gui_mainfcn (line 95)
feval(varargin{:});
Error in spm_fnirs (line 25)
gui_mainfcn(gui_State, varargin{:});
Error in
@(hObject,eventdata)spm_fnirs('push_specify_Callback',hObject,eventdata,guidata(hObject))
Error while evaluating UIControl Callback

Your help would be really appreciated.

Bests,
Bahareh