If you're interested purely in the motion (apart from the imaging analysis itself), then I suppose you could just get the mean/median/whatever from the movement vector excluding the first timepoint of the second run. But as Marko said, the realignment parameters shouldn't contain the jump. I don't remember either way since I haven't looked at them in awhile.
Chris
________________________________________
From: SPM (Statistical Parametric Mapping) [[log in to unmask]] on behalf of Andy Yeung [[log in to unmask]]
Sent: Monday, December 02, 2013 11:45 PM
To: [log in to unmask]
Subject: Re: [SPM] Fwd: [SPM] Head movement calculation
Dear Marko and everyone,
Thanks Marko for your reply! I'm doing realignment step as follows:
After clicking realignment, I create 2 sessions, and I input files accordingly, save job, run.
The resultant graphs (translation and rotation) consist of both sessions.
So when I click data statistics and find the max, min, mean, max difference etc, they are affected by between session 'jump'.
Should I interpret head movement statistics by separating the 2 sessions and run realignment steps separately?
Best,
Andy
On Mon, Dec 2, 2013 at 4:48 PM, Marko Wilke <[log in to unmask]<mailto:[log in to unmask]>> wrote:
Andy,
as Chris said, motion in between sessions is a completely different issue from motion within sessions, and spm handles it as such. Hence, the realignment parameters are saved for each individual run, and do not contain the "jump" between sessions. If you want to check the realignment parameters for each session, look at the text file saved in each session's directory, and/or use the code snippet found at https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=SPM;8b7c5540.1102
Cheers,
Marko
Andy Yeung wrote:
---------- Forwarded message ----------
From: *Andy Yeung* <[log in to unmask]<mailto:[log in to unmask]> <mailto:[log in to unmask]<mailto:[log in to unmask]>>>
Date: Mon, Dec 2, 2013 at 4:31 PM
Subject: Re: [SPM] Head movement calculation
To: "Watson, Christopher" <[log in to unmask]<mailto:[log in to unmask]>
<mailto:[log in to unmask]<mailto:[log in to unmask]>>>
Thanks Christopher, but some subjects got a sudden jump of 5-7mm in
translation when they went from session 1 to session 2. I would like to
find a way to exclude them during reporting head movement values. Are
there ways?
Still need help.
Andy
On Sat, Nov 30, 2013 at 12:02 PM, Watson, Christopher
<[log in to unmask]<mailto:[log in to unmask]>
<mailto:[log in to unmask]<mailto:[log in to unmask]>>> wrote:
Movement in between sessions shouldn't be a problem (assuming the 2
sessions weren't acquired on separate days).
________________________________________
From: SPM (Statistical Parametric Mapping) [[log in to unmask]<mailto:[log in to unmask]>
<mailto:[log in to unmask]<mailto:[log in to unmask]>>] on behalf of Andy Yeung
[[log in to unmask]<mailto:[log in to unmask]> <mailto:[log in to unmask]<mailto:[log in to unmask]>>]
Sent: Friday, November 29, 2013 10:45 PM
To: [log in to unmask]<mailto:[log in to unmask]> <mailto:[log in to unmask]<mailto:[log in to unmask]>>
Subject: [SPM] Head movement calculation
Hi everyone,
My experiment consists of 2 sessions.
I suppose for realignment step I should input the data files into 2
sessions right?
I want to exclude the single huge movement in between sessions when
I extract info from Data Statistics. How to do so?
Also, do you guys normally quote [max-min] as the movement or just
either [max-0] or [min-0]?
Thanks.
Andy
--
____________________________________________________
PD Dr. med. Marko Wilke
Facharzt für Kinder- und Jugendmedizin
Leiter, Experimentelle Pädiatrische Neurobildgebung
Universitäts-Kinderklinik
Abt. III (Neuropädiatrie)
Marko Wilke, MD, PhD
Pediatrician
Head, Experimental Pediatric Neuroimaging
University Children's Hospital
Dept. III (Pediatric Neurology)
Hoppe-Seyler-Str. 1
D - 72076 Tübingen, Germany
Tel. +49 7071 29-83416<tel:%2B49%207071%2029-83416>
Fax +49 7071 29-5473<tel:%2B49%207071%2029-5473>
[log in to unmask]<mailto:[log in to unmask]>
http://www.medizin.uni-tuebingen.de/kinder/epn/
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