Hi Sahil, in the paper we looked at the clusterwise false positive rates (FPRs) of thickness, surface area, and volume as a function of smoothing level and cluster forming threshold (CFT). I've attached plots for each measure. Thickness is much better than volume and surface area in all cases. For thickness, CFT=.05 is pretty liberal (FPR about 20%). For more stringent thresholds, the FPRs drop to 5-10% (expecting 5%). With thickness, you are safe if you use CFT=.001. This only applies to clusters that are near the 5% level. For more significant clusters, the computed p-value may be too liberal but the actual p-value may still be below 5%. We found that permutation always properly controlled the FPR regardless of measure or CFT.

Hopefully, the paper will be out soon.

doug

On 11/27/2017 11:26 AM, Sahil Bajaj wrote:

Thanks a lot Dr. Fischl. I am looking forward to hearing back from Dr. Greve soon.

That's really exciting news that a paper addressing this issue (authored by Dr. Greve and his team) will be out very soon.

Thanks for the updates !

Best, Sahil

On Thu, Nov 23, 2017 at 8:15 AM, Bruce Fischl <fischl@nmr.mgh.harvard.edu mailto:fischl@nmr.mgh.harvard.edu> wrote:

Hi Sahil

Doug has a paper submitted on this topic and will probably respond
soon, but give him a couple of days due to Thanksgiving

cheers
Bruce


On Wed, 22 Nov 2017, Sahil Bajaj wrote:

    Hi,
    I was wondering if there is any paper published by FreeSurfer
    team or
    FreeSurfer experts (after Eklund's 2016 paper) stating that
    the cluster
    failure issue is not an issue in FreeSurfer toolbox and/or
    whether CFT of
    less than 0.05 or 0.01 to estimate cortical
    thickness/volume/area maps is
    fine to use if Monte-Carlo simulations (MCZ) in FreeSurfer.

    I am looking for any such paper to cite in one of my papers I
    am working
    on.

    Thanks !
    Sahil


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