Phil,
> could you clarify why it's not DOF-3 as was suggested in Daniele's original post?
The conventional formula of converting Pearson correlation to standardized Z-score is (1/2) * ln((1+r)/(1-r)) * sqrt(N-3), where N is the sample size (number of time points in the time series in FMRI data), or (1/2) * ln((1+r)/(1-r)) * sqrt(DOF-2), in which DOF is N-1 for the typical Pearson correlation computation in a regression model with only one regressor (intercept). I just generalized the latter formula to the situation with multiple regressors.
Gang
