Dear SPMers,
I'm somewhat of a novice at SPM and hope you don't mind an elementary
question on how closeness and jitter of intermixed events affects
differential sensitivity to their BOLD effects. We wish to conduct an
event-related experiment to look at task switching. Switch effects
diminish as interstimulus intervals increase so rapid trials (2
seconds) provide the strongest psychological effect. From what I've
read, the ability to see the separate BOLD effects of switch and
non-switch trials in a design with trials this closely spaced will be
low. How will the ability to detect separate BOLD effects be impacted
as the interval varies between 2 and 5 seconds? Also, I know that
jittering will be desirable.....if our interval is X seconds, what
percentage of this interval is necessary to form helpful jitter in this
scenario?
Many thanks in advance for any help or references.
Jim
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