[Freesurfer] fdr thresholds in tksurfer compared to Nichol's function

Hi,

I've used the fdr function in tksurfer and compared the results to Tom Nichol's matlab function (http://www.sph.umich.edu/~nichols/FDR/). I use p = 10.^-abs(pfile), where "pfile" is 'sig.mgh'.

I find that the p-threshold (pID, assuming positive dependence) is usually exactly the same as the one in tksurfer (probably because you use the same algorithm..?).

But in some cases where pID is empty, which should mean that there is no suprathreshold vertex, I do get a threshold in tksurfer. Here's an example:

For one contrast where pID was returned empty in Nichol's matlab function, I got a threshold of 1.927741 in tksurfer.

Is this supposed to happen?

The output is:

MRISfdr2vwth(rate=0.05000, sign = 0, 1, only marked = 0) = 1.927741

surfer: MRISfdr2vwth with rate 0.05 and sign 0 returned threshold 1.927741

Thank you!

yours,

LMR