Thank you for the reply.
Two last quick questions:
1) I think it would be best for me to sum across lags 2-5 (which I believe correspond to time points 3-11 seconds post-stimulus) and would like to confirm this by examining the deconvolved waveforms. Exactly how do I go about doing this? I seem to be confused about how to plot the waveforms.
2) I have currently smoothed and changed the iresp files to tlrc grids. Does it matter if I do the summing before these steps, or can I do it on the smoothed/tlrc datasets?
Thanks
P.S. sorry for the questions - my adviser is currently on sabbatical