Hello SPM-ers,
We are new to Event-Related design and analysis
and decided to start with a simple single event
paradigm. The results have been mixed. Below
is a transcript of the steps we used in
conducting the statistical analysis. If you
have a chance, please let me know if I appear to
be doing everything reasonably correct. Thanks.
Ed Modestino
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SPM99 Event Related fMRI Experiment:
a flickering checkerboard shown for 2 seconds
every 5, 6 and then 7 scans (variable SOA).
This is alternated with a blank screen with a
central fixation cross. The subject was
instructed to press a pushbutton at the
beginning of the checkerboard presentation to
monitor attention and wakefulness.
TE= 800 TR= 3.97
slices=28 5 mm thick, 64*64, FOV=240
EPI image sets=198
Slice Timing:
interleaved
reference slice 2 (this is the slice taken in
the middle of the acquisition time)
ISI (TR) =3.97
TA=3.88
STATS:
upper tail F prob. threshold: 0.01
number of bins/TR: 16
sampled bin: 1
fMRI models:
specify a model
TR/ISI= 3.97
198 scans
1 condition= checkerboard
stochastic: NO
SOA: variable
vector of onsets (plugged in scan numbers
associated with
each onset of
stimulus presentation: 0 5 11 18 23 29 36 41 47
54 59 65 72 83 90 95 101 108 113 119 126 131 137
144 149 155 162 167 173 180 185 191)
variable duration: NO
parametric modulation: NONE
Events
Select a basis set: HRF alone
interactions among trials: NO
user specified regressors: 0
fMRI models:
estimate a specified model
global effects: scale
high-pass filter: specify
cutoff period: 56 (sec)
low-pass filter: Gaussian
FWHM: default of 4
model intrinsic correlations: NONE
setup trail specific F-contrasts: NO
Results:
choose spm.mat file
define a new contrast:
contrast= 1 0
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Edward Justin Modestino
M.Phil. Candidate in Cognitive Neuroscience
University of Pennsylvania
Research Assistant
Visual Processing fMRI Lab
Department of Neurology
University of Pennsylvania School of Medicine
(215) 590-5498/5499
Fax to email (775) 416-8688
http://www.sas.upenn.edu/~ejmodest/
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