Why do you want the jacobian? The surface area is a more interpretable
measure. If you use surface area, make sure you get the patch for
mris_preproc.
doug
On 4/23/12 8:07 PM, Jeff Sadino wrote:
Hello,
Thank you Michael for your input. My feeling was that surface area
would scale with ICV.
Hello,
Thank you Michael for your input. My feeling was that surface area would
scale with ICV. In any case, is there any recommendation on how to
normalize the Jacobian? My other ramble is that since it is already mapped
into a common space, would I normalize the Jacobian, or would I have to
n
Thank you everyone for your great input. After reading through all of the
suggestions and references, I like the idea of using ICV rather than global
averages, at least for this current study. However, I do have one more
question. All the papers normalize on surface area. If we want to present
*De:* Anderson Winkler
*Para:* freesurfer@nmr.mgh.harvard.edu
*Enviado:* Lunes 26 de marzo de 2012 13:56
*Asunto:* Re: [Freesurfer] Cortical Normalization Questions
Hi Jeff and all,
For normalization (i.e., divide the
erson Winkler
>>Para: freesurfer@nmr.mgh.harvard.edu
>>Enviado: Lunes 26 de marzo de 2012 13:56
>>Asunto: Re: [Freesurfer] Cortical Normalization Questions
>>
>>Hi Jeff and all,
>>
>>For normalization (i.e., divide the measurement under study by some
>>
Hi Jeff and all,
For normalization (i.e., divide the measurement under study by some
global measurement), I would not argue favourably, as this procedure can
bias the results in the opposite direction if a global effect is present.
Instead, include it as a covariate is not as harmful. My sugges
Our reply to that is here
http://bjp.rcpsych.org/content/196/5/414.2.long
which reminded me of other papers that have also used a global thickness
measure to covary for mean cortical thickness and thereby "address whether
any regional thickness differences were in excess of global cortical
thickn
Hi Michael and others,
maybe it's this one:
http://bjp.rcpsych.org/content/196/5/414.1.long
best,
-joost
On Fri, Mar 23, 2012 at 2:15 AM, Michael Harms wrote:
>
> Hi Jeff,
> I personally like the idea of using average thickness as a covariate to
> control for a reduction in "whole brain" thic
Yes, I think Mike's approach is a good one also, although you have to be clear
about the somewhat different hypothesis you are testing
On Mar 22, 2012, at 9:15 PM, Michael Harms wrote:
>
> Hi Jeff,
> I personally like the idea of using average thickness as a covariate to
> control for a redu
Hi Jeff,
I personally like the idea of using average thickness as a covariate to
control for a reduction in "whole brain" thickness, and have used that
approach in a paper. If the Abstract that you mentioned indicated that
this is flawed, I'd be curious to know what the reason was...
cheers,
-MH
Hi Jeff
yes, I think this is still our recommendation for thickness, although
perhaps David Salat can verify. As far as surface area, you might get
Anderson Winkler to send you a preprint of his newly accepted paper on
surface area comparisons and how to do them properly. I would have said
no
Hello,
For cortical thickness normalizations, Bruce said not to normalize based on
a HBM abstract (
http://www.mail-archive.com/freesurfer@nmr.mgh.harvard.edu/msg06646.html).
Is this still the consensus?
For cortical volume, it is pretty standard to normalize to eTIV.
For cortical surface area
12 matches
Mail list logo
