Hello,
I am using an awkward design. The TR is 2. The on blocks are approximately 6 seconds in duration (about 3 TR). This is followed by approximately 54 s of an off block. There is approximately 60 seconds ISI (between the onset of each on block).
Here is a list of my short blocks, 19 of them over 600 volumes, over 20.06 minutes.
Event Onsets/sec Duration
1 70 6
1 151.5 6
1 210 6
1 270 6
1 330 6
1 390 6
1 450 6
1 510 6
1 570 6
1 629.5 6
1 688 6
1 748 6
1 808 6
1 870 6
1 930 6
1 990 6
1 1048 6
1 1108 6
1 1168 6
My question involves modeling such a sparse short block design. How do I model this? What high pass filter do I use? Do I use a high pass filter of 120s? [My on blocks are approximately 6 seconds; whereas the off blocks are approximately 54 seconds, thus 60 seconds for combining on + off, double this and we have 120 seconds?) Or is there a better way to model this? Should it be modeled as an event-related design, i.e., long events?
Thanks in advance for your input!
Ed
Edward Justin Modestino, Ph.D.
Postdoctoral Research Associate
Ray Westphal Neuroimaging Laboratory
Division of Perceptual Studies
Department of Psychiatry and Neurobehavioral Sciences
University of Virginia
Email: [log in to unmask]
Phone: 434-982-5780
Fax: 434-924-1712
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