[VoxBo] Questions about Modify>Convolve

[Joonkoo Park]

When I load a condition function (in .ref) - which is simply 1's and 
0's - and add a diagonal set (or a covariate), the G Design Workshop 
displays the covariates graphically in peaks. The first "1" starts 
around 25 seconds and peaks every 16 second. When I use 
Edit>Modify>Convolve, this covariate is convolved, and the graphical 
display shows smooth hemodynamic responses.

Q1 - Why do I see a portion of hemodynamic response decreasing at the 
very beginning of the run? (I do not have any "1" at the beginning of 
the run; the first "1" happens at 25 sec) I checked that the CONVOL 
function in IDL does not do this. I guess VoxBo is doing something more 
here, but I don't understand why VoxBo is assuming a decline of 
hemodynamic response at the beginning.

Q2 - When I load the G matrix later, I can see the hemodynamics 
response graph again, but this time with jagged lines instead of smooth 
curves. Is this just a graphics issue or have my covariates actually 
changed?

The attached is the .ref file causing this phenomenon.
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;VB98
;REF1
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