Hi all :)

When I calculate the duration of the recordings, physiologic signals are always some ms longer, but not constantly the same. How do I know how fMRI and physiological signals are aligned? 

For example, for one sample I get the following:
rs-fMRI:
120 Volumes * 2500 ms/Volume = 300000 ms
Physiological Data:
19004 samples * 16 ms/sample = 304064 ms

Or is it just that timepoint zero is the same for both signals, just that physiological recording had to be stopped manualy and therefore is a little longer?

Thanks in advance :)

Norman