It's hrad to tell as the image you sent is very low res, but this
looks like a motion artefact. View the data as a movie before and
after motion correction and see if this makes sense....
Cheers.
On 13 Feb 2007, at 14:42, Clare Kelly wrote:
>
> Hello all,
>
> I've been running some connectivity analyses with resting data and
> see some fairly large rim artifact for several seeds in many of my
> subjects.
>
> I re-ran my preprocessing with melodic and I see a component such
> as the one in the attached figure in several subjects. For this
> subject (who probably showed the most severe artifact), this was
> the second component, explaining 8.16% of the explained variance
> (7.6% of the total variance).
>
> I'm planning to include the timeseries for this component as a
> nuisance covariate in my analysis, but I'm wondering if anyone has
> any idea what it is, and if it's something I can prevent in the
> future. I didn't think it could be movement as the total (absolute)
> movement in this subject was only 0.23mm, relative movement was
> 0.08mm.
>
> Thanks for your help!
>
> Clare Kelly
> <IC_2_thresh.jpg>
> <f2-t2.jpg>
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