Dear SPMers,
There has been some discussion about fractions of image onsets in the past
but I wanted to bring up that point again to gain more insight.
Is it true that using a TR of 3.0s and entering fMRI_T as 30, an IMA value
of 1.5 will cover durations of e.g. 4.46s to 4.54s? That is, SPM99 would
then sample with 100ms bins?
Using "E-Prime" for stimulus presentation you get a log that claims to be
1ms exact. However, with a repetition rate of 60Hz for the stimulus
projector, a range of 16 to 20ms seems sufficient. Does it really make sense
in this situation to enter fMRI_T as 150 to achieve sampling at 20ms? Are
fractional onset values in this range of real use for the subsequent data
evaluation in SPM99?
> PD Dr. Adrian Danek
> Cognitive Neuroscience Section, NINDS
> National Institutes of Health
> Building 10, Room 5C205
> 10 Center Drive
> Bethesda, Md 20892-1440
> e-mail: [log in to unmask]
> Fax: 301-480-2909
>
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