Right we will recommend using the areal classifier to find these areas rather 
than the group parcellation once the areal classifier is available.

Peace,

Matt.

From: 
<hcp-users-boun...@humanconnectome.org<mailto:hcp-users-boun...@humanconnectome.org>>
 on behalf of Timothy Coalson <tsc...@mst.edu<mailto:tsc...@mst.edu>>
Date: Wednesday, October 4, 2017 at 4:36 PM
To: Romuald Janik <romuald.ja...@gmail.com<mailto:romuald.ja...@gmail.com>>
Cc: "hcp-users@humanconnectome.org<mailto:hcp-users@humanconnectome.org>" 
<hcp-users@humanconnectome.org<mailto:hcp-users@humanconnectome.org>>
Subject: Re: [HCP-Users] Surfaces, coordinates and beginner questions

This is not something that QC can catch, it requires extensive processing to 
discover this.  The individual subject parcellations that are generated during 
the MMP 1.0 process do reflect these differences, so these will be able to be 
used instead of the group label map when using HCP data.

I believe these issues affect relatively few areas and are somewhat rare, for 
instance 55b (and therefore also some of its neighbors) is one of the most 
affected areas, however 89% of subjects had the typical pattern for 55b.  See 
"Individuals with atypical areal patterns" supplemental information in the MMP 
paper:

https://www.ncbi.nlm.nih.gov/pubmed/27437579

Tim


On Wed, Oct 4, 2017 at 1:38 PM, Romuald Janik 
<romuald.ja...@gmail.com<mailto:romuald.ja...@gmail.com>> wrote:
Thanks for the detailed explanations!

I have just one follow up question regarding this point:

On Tue, Oct 3, 2017 at 11:57 PM, Timothy Coalson 
<tsc...@mst.edu<mailto:tsc...@mst.edu>> wrote:


Some techniques like hyperalignment use this "correspondence" concept 
aggressively, and allow you to have discontinuities (this area is on the 
"wrong" side of this other area in this subject - we have evidence that some 
subjects do actually have areas shifted or split), however MSMAll doesn't allow 
this (the constraints it imposes to prevent this make the problem easier to 
solve, and possibly more robust to noise).  When we talk about "spherical 
distortion", we are talking about artifacts of this "correspondence-finding" 
process, there is still no anatomical distortion caused to individual data.



Such splitting or shifting of areas would make comparisons with other subjects 
(like averaging statistics etc.) in principle problematic - also using the 
MMP1.0 parcellation for these subjects would be wrong for these areas. Are 
these subjects indicated in some way? (like having the QC_Issue codes A or B? 
or these problems are more subtle?)
Once again many thanks,
Romuald




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