I have a block design experiment. After analyzing the data and plotting the response magnitude across the TRs, we see that there is a systematic lag in the response. For example, in a 16s block (TR=2s), at TR-1 and TR-2 the response goes down and then starts rising from TR-3. This is consistent across the subjects and blocks. 

We used to shift our raw data by 2 TRs when we were using SPM. 

How can we do this in FreeSurfer?

Thank you,

Sarah