I am just a new comer to use SPM and doing fMRI experiment. I have
encountered much difficulty in analyzing the data now. My experiment
design is a block design and the acquisition is a cluster acquisition
because it will allow for silence to present auditory stimulus.
Should I follow the Event-related analysis? In slice timing, what should I
put as TA? Is it the start time of the last slice acquisition? For
example, I have 32 slices, and they are acquired in 1.6s. Is the TA 1.55?
In the original experiment, I did the continuous acquisition and the TR is
2000ms. In the cluster acquisition, the TR is 3000ms and TD is 1400ms
allowing for silence. But the analyzed results are very different. In the
first case, most contrasts show significant differences, while in the
second case, little contrasts show differences.
I think the slice order and reference slice are all set right. What would
be the reason for such large differences? How can I check my analyze
result? I am feeling desperate about the situation now.
Thank you for your help!!