Hello,
I have a pretty basic question:
Suppose I have and fMRI experiment with two conditions (condition A and condition B).
I want to test if condition A is associated with more BOLD signal intensity compared to
condition B. This would be a [1 -1] contrast. Correct?
I now want to test if condition B is associated with more BOLD signal intensity compared
to condition A. This would be a [-1 1] contrast. Correct?
Now I want to know if compared to no condition (baseline), either A or B are associated
with a higher BOLD signal intensity. This would be a [1 1] contrast. Correct?
The above tests correspond to t-tests. What would an F-test with the following contrast
[1 -1
-1 1]
show. Wouldn't that be the same question as the [1 1] contrast above?
Where I am getting with this is how I set up contrasts to find A. activation only B.
deactivation only and C. activation and deactivation. I assume the latter (activation or
deactivation) would be an F-test. How would I set that question (Is there either activation
or deactivation) up in a second level analysis?
Hope these questions make sense.
Michael
University of Alabama
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