On 4/18/2024 1:59 PM, Tejaswi D. Sudhakar wrote:

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Hello Freesurfer team,

I am interested in doing one glm analysis using both the thickness and cortical surface area.

My question is two-fold:

First, is it possible to provide both the thickness and area files to mris_preproc and mri_surf2surf commands or is it only possible to run two separate glms (one for thickness and one for area)?

You must run two separate glms

Second, can we consider thickness and area as separate values or are they both correlated? In other words, how correlated are the thickness and area values?

They should be uncorrelated by construction (ie, the noise in the thickness should be uncorrelated from that in the area), but they may biologically correlated (don't know). When doing an area analysis, make sure to turn on jacobian correction (on by default when you spec area to mris_preproc) and correct for total head size. You will also need to do the permutation corrections for multiple comparisons (for both thickness and area but esp for area).

Thanks in advances,

Tejaswi

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