You should smooth your images. Typically, researchers use 6mm for DARTEL.
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Postdoctoral Research Fellow, GRECC, Bedford VA
Research Fellow, Department of Neurology, Massachusetts General Hospital and Harvard Medical School
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
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On Jul 15, 2013, at 4:47 AM, Antoinette Nicolle <[log in to unmask]> wrote:
> Hi SPMers,
>
> Sorry for reposting this same message but I didn't receive a response and I hope someone can advise me.
>
> I'm attempting to use Ged Ridgway's get_totals script to extract grey matter volume from some ROIs but I'm unsure whether it is appropriate to do this with smoothed images or whether I need to have unsmoothed images.
>
> I've used Dartel to get my modulated, normalised, smoothed images but, as I understand it, my images will suffer from "aliasing" artifacts if I set the smoothing to 0, 0, 0. Presumably, then, I need to use smoothed data if I want to use Dartel? But is it appropriate to extract grey matter volume from smoothed images? Perhaps if I were to smooth my images by a very small kernel (e.g. 1.5, 1.5, 1.5)?
>
> Many thanks,
> Antoinette
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