Dear SPM group,
In planning event related fMRI experiments with the expectation of
analysis by SPM99 I am wondering what the minimum average ISI can be. We
would like to optimize the number of stimuli we can present in a scan
session. Assume the ISI is randomized within a defined window about the
mean ISI and a TR of 3.3s for whole brain acquisition. I realize that with
ISI's less than 16-20s we will limit our ability to characterize
differential onset and temporal pattern of HRFs. So my question is, if we
primarily want to detect relative HRF amplitude differences among classes of
items, what is the smallest mean ISI that can be appropriately analyzed by
SPM99. Has anyone tested this or run simulations? I'd greatly appreciate any
thoughts.
Best wishes,
Andy Saykin
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Andrew J. Saykin, Psy.D., ABPP-CN
Associate Professor
of Psychiatry and Radiology
Brain Imaging Laboratory
Psychiatry/DHMC
Dartmouth Medical School
Lebanon NH 03756
USA
email: [log in to unmask]
phone: 603-650-5824
fax: 603-650-5842
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