secs to TR

SPM use FIR models to calculate the PSTH (peri-stimulus time histogram). By default, the FIR models have a time bin of one TR. Let us imagine your TR is one second, as is your FIR time-bin. You can then think of the FIR as calculating the best estimate of the signal 0 seconds, 1 seconds, 2 seconds after the event has occurred, and after adjusting for other effects in the model.

Ollinger JM, Shulman GL, Corbetta M. Separating processes within a trial in event-related functional MRI. Neuroimage. 2001 Jan;13(1):210-7.

Dale AM. Optimal experimental design for event-related fMRI. Hum Brain Mapp. 1999;8(2-3):109-14.

From:

MarsBaR F&Q