[pymvpa] Temporal filtering and smoothing

[Yaroslav Halchenko]

On Wed, 11 Apr 2018, Alyson Saenz wrote:

>    Dear PyMVPA community,
>    Hi, it has being a while since I worked with a new database, I'm starting
>    a new project and was about to do some preprocessing, I remember to have
>    read somewhere that it was recommended not to apply temporal filtering to
>    the data nor smoothing. 

"It depends" ;-)

> I did found the no smoothing part, but I havent
>    had any luck with the temporal filtering part. I'm also concern that I
>    might not remember something important or that there have been some new
>    findings in similar regards, so, just to be sure.
>    Can anyone tell me what kind of preprocessing is recommended?

It depends on what effects you are aiming for, and classification task.
Typically at least some minor spatial "smoothing/filtering" (~4-6mm
gaussian) and temporal filtering  lowpass (to despike motion etc) and
highpass (to remove lengthy trends, might be done via regressing out
nuisance regressors such as first N PCA components from ventricles etc).

-- 
Yaroslav O. Halchenko
Center for Open Neuroscience     http://centerforopenneuroscience.org
Dartmouth College, 419 Moore Hall, Hinman Box 6207, Hanover, NH 03755
Phone: +1 (603) 646-9834                       Fax: +1 (603) 646-1419
WWW:   http://www.linkedin.com/in/yarik        
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