Re: [Freesurfer] Freesurfer templates for cross-ethnicity comparisons

2014-01-09 Thread Bruce Fischl

Hi Mike

nice to be right once in a while :). You shouldn't have to register to an 
atlas brain to build the folding pattern template though - you can pick 
one of your own dataset to start with.


cheers
Bruce
On Thu, 9 Jan 2014, Michael Chee 
wrote:



Hi Bruce and Linda,

Yes, this is my work email. Pacific internet shut down email operations in
Singapore in Dec 2012…

We built an ‘Asian Only’ template with around 30 Chinese participants but
the use of this template did not generate a result that differed from that
obtained using the stock MGH template. We were quite disbelieving of Bruce’s
prediction that this would be so but he proved to be correct. The caveat
(and its not a small one) is that to BUILD the template, one has to register
to an atlas brain which is presumably Caucasian weighted. 

The paper comparing predominantly Caucasian and Chinese brains using FS was
published in 2011 in J Cog Neurosci and can be found on my lab website. We
did not mention building the custom atlas in that work because of the lack
of a difference in using this vs. the standard template. 

Zheng Hui (copied) did all the hard work on this.


Michael Chee MBBS, FRCP(Edin)
Professor
Cognitive Neuroscience Laboratory
Neuroscience and Behavioral Disorders Program
Duke-NUS Graduate Medical School
8 College Rd, #06-18
Singapore 169857.

email: michael.c...@duke-nus.edu.sg   
office: (65) 65164916
CNL Home page: http://www.cogneuro-lab.org

From: Bruce Fischl fis...@nmr.mgh.harvard.edu
Date: Thursday, 9 January, 2014 5:24 am
To: Linda Zhang lzhan...@gmail.com
Cc: Freesurfer freesurfer@nmr.mgh.harvard.edu, Michael Chee
michael.c...@duke-nus.edu.sg
Subject: Re: Freesurfer templates for cross-ethnicity comparisons

Hi Linda

I had an old address for Mike in the first email. I think this one is
correct. Building a folding atlas is pretty quick, depending on how many
subjects you have. You'll need to pick one subject, run mris_make_template
to build a single-subject template (for each hemi), register everyone to
it, rerun mris_make_template to build a multi-subject atlas, rerun
mris_register with the new atlas as the target and iterate this procedure
until it converges (atlas building and reregistering). Usually it does
after only one additional round.

cheers
Bruce




On Wed, 8 Jan 2014, Linda Zhang wrote:

  Thanks Bruce!  How long would it take to build an atlas?

What are your thoughts Mike?


On 7 January 2014 14:38, Bruce Fischl fis...@nmr.mgh.harvard.edu
wrote:
  Hi Linda

I actually don't know the ethnicity of the subjects in our
atlas. I wouldn't
expect it to be an issue for folding patterns, but it is
possible. You could
build your own atlas and redo the analyses if you want to see if
that
changes things. I'll cc Mike Chee who I think has looked at this
question as
well.

cheers
Bruce





On Tue, 7 Jan 2014, Linda Zhang wrote:

  Hi Bruce,

I've been using Freesurfer to compare subcortical volumes
and cortical
thickness between Caucasian and Chinese controls.  There
are some
significant findings, but the question of whether or not
these may be
biased due to the template has been raised (the assumption
being that
the majority of subjects used in the template are
Caucasian).  Is it
possible to reduce the weight of the atlas during
normalisation (or
some other method to address the issue)?  I would greatly
appreciate
your thoughts on this.

Cheers,
Linda





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Re: [Freesurfer] Freesurfer templates for cross-ethnicity comparisons

2014-01-08 Thread Linda Zhang
Thanks Bruce!  How long would it take to build an atlas?

What are your thoughts Mike?


On 7 January 2014 14:38, Bruce Fischl fis...@nmr.mgh.harvard.edu wrote:
 Hi Linda

 I actually don't know the ethnicity of the subjects in our atlas. I wouldn't
 expect it to be an issue for folding patterns, but it is possible. You could
 build your own atlas and redo the analyses if you want to see if that
 changes things. I'll cc Mike Chee who I think has looked at this question as
 well.

 cheers
 Bruce





 On Tue, 7 Jan 2014, Linda Zhang wrote:

 Hi Bruce,

 I've been using Freesurfer to compare subcortical volumes and cortical
 thickness between Caucasian and Chinese controls.  There are some
 significant findings, but the question of whether or not these may be
 biased due to the template has been raised (the assumption being that
 the majority of subjects used in the template are Caucasian).  Is it
 possible to reduce the weight of the atlas during normalisation (or
 some other method to address the issue)?  I would greatly appreciate
 your thoughts on this.

 Cheers,
 Linda





 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
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Re: [Freesurfer] Freesurfer templates for cross-ethnicity comparisons

2014-01-08 Thread Bruce Fischl
Hi Linda

I had an old address for Mike in the first email. I think this one is 
correct. Building a folding atlas is pretty quick, depending on how many 
subjects you have. You'll need to pick one subject, run mris_make_template 
to build a single-subject template (for each hemi), register everyone to 
it, rerun mris_make_template to build a multi-subject atlas, rerun 
mris_register with the new atlas as the target and iterate this procedure 
until it converges (atlas building and reregistering). Usually it does 
after only one additional round.

cheers
Bruce




On Wed, 8 Jan 2014, Linda Zhang wrote:

 Thanks Bruce!  How long would it take to build an atlas?

 What are your thoughts Mike?


 On 7 January 2014 14:38, Bruce Fischl fis...@nmr.mgh.harvard.edu wrote:
 Hi Linda

 I actually don't know the ethnicity of the subjects in our atlas. I wouldn't
 expect it to be an issue for folding patterns, but it is possible. You could
 build your own atlas and redo the analyses if you want to see if that
 changes things. I'll cc Mike Chee who I think has looked at this question as
 well.

 cheers
 Bruce





 On Tue, 7 Jan 2014, Linda Zhang wrote:

 Hi Bruce,

 I've been using Freesurfer to compare subcortical volumes and cortical
 thickness between Caucasian and Chinese controls.  There are some
 significant findings, but the question of whether or not these may be
 biased due to the template has been raised (the assumption being that
 the majority of subjects used in the template are Caucasian).  Is it
 possible to reduce the weight of the atlas during normalisation (or
 some other method to address the issue)?  I would greatly appreciate
 your thoughts on this.

 Cheers,
 Linda





 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
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 but does not contain patient information, please contact the sender and
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[Freesurfer] Freesurfer templates for cross-ethnicity comparisons

2014-01-07 Thread Linda Zhang
Hi Bruce,

I've been using Freesurfer to compare subcortical volumes and cortical
thickness between Caucasian and Chinese controls.  There are some
significant findings, but the question of whether or not these may be
biased due to the template has been raised (the assumption being that
the majority of subjects used in the template are Caucasian).  Is it
possible to reduce the weight of the atlas during normalisation (or
some other method to address the issue)?  I would greatly appreciate
your thoughts on this.

Cheers,
Linda
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dispose of the e-mail.



Re: [Freesurfer] Freesurfer templates for cross-ethnicity comparisons

2014-01-07 Thread Bruce Fischl
Hi Linda

I actually don't know the ethnicity of the subjects in our atlas. I 
wouldn't expect it to be an issue for folding patterns, but it is possible. 
You could build your own atlas and redo the analyses if you want to see if 
that changes things. I'll cc Mike Chee who I think has looked at this 
question as well.

cheers
Bruce




On Tue, 7 Jan 2014, Linda Zhang wrote:

 Hi Bruce,

 I've been using Freesurfer to compare subcortical volumes and cortical
 thickness between Caucasian and Chinese controls.  There are some
 significant findings, but the question of whether or not these may be
 biased due to the template has been raised (the assumption being that
 the majority of subjects used in the template are Caucasian).  Is it
 possible to reduce the weight of the atlas during normalisation (or
 some other method to address the issue)?  I would greatly appreciate
 your thoughts on this.

 Cheers,
 Linda



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