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I've done it with 1mm voxels - it comes out to 1.21 million voxels in the mask for an analysis. It ran fine on my machine but it is 64 bit so perhaps that is why. ----- Darren Gitelman On Wed, Apr 22, 2009 at 10:00 PM, MCLAREN, Donald <[log in to unmask]>wrote: > I've done .5mm^3 in macaques, but that only had 700,000 voxels, which > is less than a human processed at 1.5mm. > > Human data (assuming LR is 160mm, SI is 149mm, APis 193mm) yield ~1.2 > million voxels @1.5mm or ~4.6million voxels @1mm isotropic resolution. > > I'm not sure what the time trade off is for the higher resolution. > > On Wed, Apr 22, 2009 at 6:17 PM, Jeff Browndyke <[log in to unmask]> > wrote: > > I would add to Philipp's cogent response below that the simple > > calculation is complicated by the default voxel dimensions preferred by > > Dartel and most computers (i.e., 1.5 mm3). This prompts me to ask...has > > anyone successfully run Dartel at 1mm3 voxel size output? > > > > Jeff > > > > > > > > ________________________________ > > > > Jeffrey N. Browndyke, Ph.D. > > Duke University Medical Center > > 2200 West Main St., Suite A-200 > > Durham, NC. 27705 > > _________________________________ > > > > > > -----Original Message----- > > From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] > > On Behalf Of Saemann Philipp > > Sent: Wednesday, April 22, 2009 1:11 PM > > To: [log in to unmask] > > Subject: Re: [SPM] Relationship between probability maps and volume > > > > Hello, > > > > what you suggested as answer is basically true for the modulated GM > > images > > (i. e. images that have been produced by the segmentation algorithm or > > DARTEL > > with the modulation step switched on). > > > > Only the modulation step garantues the transition of the probability > > value > > to a volume value. > > Then, the resulting value of the voxel is - in practical terms - > > directly > > equivalent to a volume. A value of 1 in a voxel of > > 1x1x1 mm3 would (theoretically) be equivalent to 1 microliter. > > > > As lit. you could cite basic papers e. g. of John Ashburner on voxel > > based > > morphometry in general, > > or Unified Segmentation, or the diffeomorphic algorithm of DARTEL - > > depends, on what you did. > > > > All links to the literature you find on the SPM homepage & the > > respective > > sections. > > > > Hope this helps, > > Philipp > > > > Max Planck Institute of Psychiatry > > NMR Research Group > > Kraepelinstr. 2-10 > > 80804 Munich > > Mail: [log in to unmask] > > Phone: 0049-89-30622-413 > > > > > > -- > Best Regards, Donald McLaren > ===================== > D.G. McLaren > University of Wisconsin - Madison > Neuroscience Training Program > Office: (608) 265-9672 > Lab: (608) 256-1901 ext 12914 > ===================== > This e-mail contains CONFIDENTIAL INFORMATION which may contain > PROTECTED HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED > and which is intended only for the use of the individual or entity > named above. If the reader of the e-mail is not the intended recipient > or the employee or agent responsible for delivering it to the intended > recipient, you are hereby notified that you are in possession of > confidential and privileged information. Any unauthorized use, > disclosure, copying or the taking of any action in reliance on the > contents of this information is strictly prohibited and may be > unlawful. If you have received this e-mail unintentionally, please > immediately notify the sender via telephone at (608) 265-9672 or > email. >