Hi David - The path.map file is the maximum a posteriori (MAP) estimate of the path. That is, of all the paths that were generated by the algorithm and summed to create the posterior distribution path.pd, this is the path that on average over all its voxels maximizes the posterior probability given the data. Thus this is just a single path (a one-dimensional curve) and not a thresholded version of path.pd. You could create a new ROI by thresholding path.pd at your desired level if you wanted to get statistics of the FA, MD, etc at a new threshold.
Hope this helps, a.y
On Tue, 23 Aug 2011, David Coynel wrote:
Dear experts, Could you please tell me how the path.map for a given pathway is computed, and especially if it is a thresholded version of the posterior distribution path.pd. In this case, would it be possible to re-run the tract-statistics using different path.map files ?
Thank you Dr. David Coynel Division of Cognitive Neuroscience
University of Basel Birmannsgasse 8 4055 Basel - Switzerland
david.coynel@unibas.ch tel: +41(0)612.670.240
Am 23.08.2011 um 04:03 schrieb Anthony Dick:
The subcortical segmentation identifies subcortical structures such as thalamus, basal ganglia structures, hippocampus, amygdala, and cerebellum. The cortical parcellation delineates different areas of the cortex, such as the superior temporal sulcus, the central sulcus, the pars triangularis, opercularis, and orbitalis of the inferior frontal gyrus. A recommendation is to get a copy of the Duvernoy atlas, which covers definitions of different parts of the cortex. The Mai atlas is good for learning subcortical structures. On 8/22/11 9:45 PM, Kenichiro Tanaka wrote: Hello All, I have a question about "segmentation" and "parcellation". What is the difference between the subcortical segmentation and the cortical parcellation? Especially I do not understand the difference between subcortical and cortical and between segmentation and parcellation. I tried to read FreeSurfer Wiki, but I did not understand it well. Could you tell me it? Thanks. Kenichiro Tanaka. _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail. -- Anthony Steven Dick, Ph.D. Assistant Professor Department of Psychology Florida International University Modesto A. Maidique Campus DM 296B 11200 S.W. 8th Street Miami, FL 33199 Phone: 305-348-4202 Fax: 305-348-3879 Email: adick@fiu.edu Webpage: http://www.fiu.edu/~adick _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer