Sherif,
Take a look at these papers and others that cite them:
Liu, T. T., Frank, L. R., Wong, E. C., & Buxton, R. B. (2001). Detection power, estimation efficiency, and predictability in event-related fMRI. Neuroimage, 13(4), 759-73.
and look at
Neuroimage 2003 Mar;18(3):806-10. [MEDLINE]
Comparing event-related and epoch analysis in blocked design fMRI.
Mechelli A, Henson RN, Price CJ, Friston KJ.
Best of luck,
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Robert C. Welsh, PhD
Research Investigator
Department of Radiology
University of Michigan
(734) - 764 - 2412 (fax)
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>>> Sherif Karama <[log in to unmask]> 11/11/05 12:46 AM >>>
Dear SPM users,
I need a little help responding to a reviewer's comment.
We have shown, in a submitted manuscript, that a conventional short block design (around 30 sec per block) was more efficient than longer block designs (e.g. 180 sec per block) for a given type of study. Obviously, not a surprise...
In the manuscript, we explain this by the decreased susceptibility of shorter block designs to low frequency noise.
A reviewer comments that we have not considered the possibility that "shorter blocksf (all being equal) allow more 'contrast' data to be obtained in a given time and THEREFORE increase statistical power".
Is this correct?
Thanks in advance,
Sherif
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