Dear Bosky
The approach which I prefer is to let the high-pass filter cut-off be
determined by your hardware (irrespective of your choice of paradigm).
You can do this using a phantom and diagnostic statistics as
implemented in SPMd. With this approach you can justify that the system
drift is modelled adequately with a particular high-pass filter on your
scanner using a particular sequence.
Best regards,
Torben
Torben E. Lund
Danish Research Centre for MR
Copenhagen University Hospital
Kettegaard Allé 30
2650 Hvidovre
Denmark
email: [log in to unmask]
webpage: http://www.drcmr.dk
On 30 Jul 2005, at 20:18, Bosky wrote:
> Hello SPM experts:
>
> Is there a general rule for setting the High Pass Filter for a rapid
> event related design? Our design has 3 blocks , each of a different
> fixed duration. Within the first block , 2 types of stimuli are
> presented in a random fashion; in the second block, 3 types of stimuli
> are presented in a random fashion and the last block is the same as
> the first block( i e , 2 types of stimuli). For the first
> block, duration of each stimulus is 1 second and each stimulus is
> followed by an orientation cross of varying duration. In the second
> block, 2 stimulus is presented for 1 second while the 3rd one lasts
> for 2 secs.
>
> What should be my High pass filter setting for such a design. I have
> read that there is no strict rule for event related designs but one
> can set is to atleast 50s. Kindly help.
>
> Thanks,
>
> Bosky Ravindranath
>
>
>
> Laboratory for the Study of Emotion and Cognition,
> Department of Biomedical Engineering
> Stony Brook University,
> New York, 11790
> Phone- 631-444-8405/ 631-444-7868
>
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