> From [log in to unmask] Tue Sep 28 09:26:58 1999
> Original-Sender: [log in to unmask]
> Date: Tue, 28 Sep 1999 10:27:05 +0200
Dear Christian,
> Again, please assume the following fMRI-experiment where eight
> conditions are presented pseudo-randomised:
>
> C A D G B F R* E G C F B D A E R* B D A C F D R* E
>
> R* refers to "Rest". Each condition is repeated three times and lasts
> 30 sec (TR 3 sec). What would the appropriate HPF cut-off be in this
> case?
>
> Following previous comments on this issue I am not sure about the
> biggest minimum interval for this kind of experiment. If we take the
> minimum SOA for the rest condtion (70 scans) would it be reasonable to
> specify a HPF of 420 (210 sec * 2)?
Because you have multiple conditions you can afford to use a smaller
cutoff period than twice the maximum (within conditions) minimum (among
conditions) SOA. This is because condition-specific differences have
frequency components higher then the fundamental frequency. There is no
absolute rule but you could try anything between 120 and 420 seconds.
I hope this helps - Karl
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