in general people have not found much of a relationship between ICV and thickness, so correcting for icv just reduces your # of degrees of freedom without removing any unwanted variance. You can remove the global mean thickness, which is testing a slightly different hypothesis than not doing so.

cheers Bruce On Mon, 25 Jan 2010, lordowen wrote:

Hi, Bruce:

Why should not be corrected for thickness? Or you mean the cortical thickness should be corrected using mean thickness but not intracranial volume? Can you explain more?

Thank you for your advise.

2010/1/23 Bruce Fischl fischl@nmr.mgh.harvard.edu:

...

Hi LJ,

yes, the volume of the amygdala is in the stats/aseg.stats file for each subject. There should also be an estimated intracranial volume and brain size that you can use to account for either one (which represent somewhat different hypotheses). In general I think the consensus is that volumes should be corrected, but not thickness.

cheers Bruce

On Sat, 23 Jan 2010, liyari5018 wrote:

...

Hi all, When I completed the recommended recon-all step, I want to get the volume(or size) of amygdala for ecah individual subject and to do correlation analysis with psychological scale, how can I do this ??? For a group level analysis , should i do some head size correction befor ???

Thanks for your reply!!! L J

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