Does anybody know: are the graphs that SPM produces with motion
correction graphs of motion detected, or of motion corrected?
--Steve
> Hello Lila,
> two relevant things beyond what Russel mentioned is that rotational
> motion is much more difficult to correct for and thus more critical when
> deciding to further analyze the data or not. The 2nd issue is whether
> your motion peaks are correlated with your events or not. If so, motion
> correction might strongly influence your signal.
> Regards, Bartosz
>
>> On Aug 2, 2005, at 7:54 AM, Lila Davachi wrote:
>>
>>> Hi all
>>> I am looking for some guidance into how to decide if a subject has
>>> simply moved "too much", in other words, how much motion is too much
>>> motion?
>>>
>>> I have been using a shorthand guide and only have included Ss who
>>> moved less then one voxel (in this case, 3mm) and trusted that
>>> motion correction could handle that. But does the kind of motion
>>> matter? For example, I have a subject now who only moved ~ 2mm across
>>> a 1/2 hour scan but the motion was concentrated at specific times
>>> with sharp peaks in the graph.
>>>
>>> So, my question is how can I convince myself that SPM has done a good
>>> job at correcting the motion?
>>> What are some tests of the data that I can implement (besides
>>> including motion as a regressor..).???
>>>
>>> thanks much
>>> lila
>>>
>>
>> ---
>> Russell A. Poldrack, Ph.d.
>> Assistant Professor
>> UCLA Department of Psychology
>> Franz Hall, Box 951563
>> Los Angeles, CA 90095-1563
>>
>> phone: 310-794-1224
>> fax: 310-206-5895
>> email: [log in to unmask]
>> web: www.poldracklab.org
>>
>>
>
> --
> Dr. Bartosz Zurowski
> Klinik für Psychiatrie und Psychotherapie
> UKSH Campus Lübeck
> &
> Department of Systems Neuroscience
> NeuroImage Nord, Bldg. S10, UKE
> Martinistrasse 52 phone: 040-42803-3683
> 20246 Hamburg fax: 040-42803-9955
>
|