Hello Courtney,
1. The realignment parameters (translation and rotation) estimated during the realignment step are saved in the same folder as your data in a txt named rp_*txt.
You can directly load this text file in matlab and plot them.
2. If you formulate a model considering the HRF derivatives, it is recommendable that you specify an F-contrast.
You can have a look to Chapter 7 in the Human Brain Function Book, http://www.fil.ion.ucl.ac.uk/spm/doc/books/hbf2/
This chapter explains the differences between T-test and F-test and how to specify contrasts.
Hope this helps,
Cesar
On Sep 22, 2010, at 12:32 AM, Courtney Brown wrote:
> Hello all,
>
> I have two somewhat unrelated issues I am hoping others will be able to shed some light on for me:
>
> 1. I have preprocessed my data and would like to view movement parameters for individuals. The SPM manual discusses a specific file holding the movement parameters (with a prefix "rp"). Does SPM automatically generate this file during realignment (I used the "realign and unwarp" option)? If so, is there a specific folder where it saves this file? If it does not generate such a file, is there a method available to view movement parameters after processing has moved beyond the realignment phase?
>
> 2. I have an event-related study involving a sample of healthy young adults (TR = 2 sec, 2 conditions of interest). I am debating use of the HRF derivatives to allow for more subject-subject and voxel-voxel HRF differences to be taken into account. How would one specify the contrasts in order to take both derivatives into account when comparing conditions of interest? Also, are there factors that would deem only 1 type of derivative as necessary rather than needing to include both within the model?
>
> Any input would be greatly appreciated.
>
> Thank you,
>
> Courtney Brown, B.A.
> Graduate Student
> University of Georgia
> Department of Psychology
> Athens, GA 30602
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