I need to find correlation of 3D+time with a time series I found function 3dTcorr1D which seems to do just that

2 questions:
1) I need to get the corrcoef along with the significances (or some stat that I can threshold for significance) in the description of function there is no mention of whether p values can be accesses ( e.g. looks like only 1 volume is returned per column of 1D input)

2) -pearson correlation option is mentioned to be a dot product. Is this calculated after subtracting the averages from to be correlated signals or should we demean the inputs before ourselves?

thanks
Ali