Thanks very much for your responses everyone! This does make a lot of
sense. Just to verify, I would have 9 conditions (blocks A,B,C, events
1,2) set up like this:
blocks (duration 30)
events (duration 0)
which equals 9 conditions (i.e., not A1, A2, B1, etc. with 30 duration).
Thanks for verifying!
Jonathan Peelle wrote:
> 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:
>> 14 16 21 22 24 25 136 137 145 149 150 158
>> 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
> 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,