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Hi Esther

A quick response to your last question:

> Quickly with regard to the conditions: I want to use a factorial design, so
> I believe I need to set up my conditions as indicated (6 total).
>
> The way I am doing this right now is as follows: I include the block onsets
> together with event onsets in the same condition file, i.e., if one run has
> two blocks and five events per block, the input would look like this:
>
> onsets:
> 14 16 21 22 24 25  136 137 145 149 150 158
> duration:
> 30 0 0 0 0 0 30 0 0 0 0 0

The problem with this approach is that by including both the sustained
and transient activity in the same condition, you make it impossible
to separate the two effects.  I think what you want, as Donald
suggested, is 9 conditions:

block 1 (duration of 30 sec)
A in block 1 (duration of 0)
B in block 1

block 2 (duration of 30 sec)
A in block 2
B in block 2

etc.

This should let you test for all of the main effects and interactions
in your design.

I wouldn't think you would need to worry about different shapes of
HRF.  If there is indeed sustained activity during these blocks, then
I would think that the standard SPM convolution with the HRF would
reflect this.  If you did want to use different basis sets, I don't
think there is a way to do this in the GUI; you would probably have to
write some code to do this.

Hope this helps,

Jonathan