Dear SPM experts,

I re-submit this mail b/c I’m still in trouble.

 I’m very new SPMer and statistical approach, so making effort to catch up and understand the procedure.

For now, I’m trying to analyze multi-subject NIRS data based on FDR.

 I found that we can get the threshold for activation from ‘spm_uc_FDR.m’.

 In the ‘spm_uc_FDR.m’, it converts the t-values (which I’m using) to p-values, sort p-values,

find the p-value’s index which decides the activation, and get the threshold from reconverting the p-value to t-value.

Am I understanding well?

If it’s right, here’s some question.

1) In the spm_uc_FDR.m, there’s some code, ‘Ps = (1-spm_Tcdf(Ts,df(2))).^n;’

   I’m not sure what the conjunction number ‘n’ means.

   For now, I’m doing work with 5 subjects’ data (they did same task),

in this case, how do I determine the conjunction number?

2) and, we need degree of freedom for converting between t-values and p-values.

   As far as I know, degree of freedom is the number of subject (minus one) for multi-subject analysis.

   So, for my case, I thought it has range from 0~4. Is that right?

Actually, I could not see any activation from that. That’s why I’m confused.

In each individual analysis, I can see the activation. And those df values are around 90~92

 Any suggestion or advice would be very appreciate for me.

 Thank you.

 Jin