Hi Cedric,
this is as expected, the data changes when using the longitudinal stream (it will become more reliable, removing some of the variance you get in the independent processing). Becuase of the different processing approaches, the results from independent processing (cross) and long will not be directly comparable.
Cheers, Martin
On 06/25/2013 04:02 AM, Koolschijn, Cédric wrote:
Hi FreeSurfers,
I ran the longitudinal processing pipeline on my subjects, FS 5.0. Following the tutorial, first independently, then base, then long etc. Everything works well, no problems there.
Out of curiosity I compared the asegstats & aparcstats within subject at baseline (i.e. The same timepoint): so the independent fsid vs the same_fsid.long.same_fsid_template, and there are (large) differences between all volumes/thicknesses. The independent measures are in almost all brain areas larger compared to those derived from the longi-stream. Except for the IC, which is completely the same, but of course, this measure is based on the Buckner method and calculated differently.
Overall this seems a bit strange to me, because I believe there shouldn't be differences within subject on the same time-point. Is this the result of the within-subject template use for the longitudinal data or is something else going wrong, or is this normal?
Many thanks!
Cheers, Cédric
P.C.M.P. Koolschijn (Cédric), PhD Dutch Autism & ADHD Research Center Brain and Cognition Amsterdam, The Netherlands /E /P.C.M.P.Koolschijn@uva.nl mailto:P.C.M.P.Koolschijn@uva.nl /W /http://www.dutcharc.nl
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