I am trying to run 3dDeconvolve with the tent functions. I ran an event related design with a stimulus presentation time of 3 s and an inter stimulus interval of 1 s. My TR is 2.5 and i chose tent (0,12,6). I get the warning:
ESC[7m*+ WARNING:ESC[0m -stim_times 1 … TENT(0,12,6) has inter-knot TR=2.4 but -iresp output TR=2.5
++ ** GUESSED ** -stim_times 1 using LOCAL times
ESC[7m*+ WARNING:ESC[0m -stim_times 2 … TENT(0,12,6) has inter-knot TR=2.4 but -iresp output TR=2.5
++ ** GUESSED ** -stim_times 2 using LOCAL times
Is this a problem for my analysis? And would it be better to change the expected response duration to 13, so that I end up with a slightly higher inter-knot time (than my TR) of 2.6 instead?
It is not clear to me based on what criteria I should chose the expected response duration and the number of tent functions. What would be the perfect parameters for the tent functions in this case?
Thank you very much