Dear Dr. Morita,
> Is a meaning of "epoch" correct?)
Yes
> number of conditions or trials : 1
> (is this correct? Should I enter "2"?)
Yes. With one condition alternating with rest it is appropriate to model the
rest implicitly by specifying just the active condition onsets. To use 2
conditions would not be wrong, but is redundant.
> I do not use high-pass filter and low-pass filter.
> (should I use these filter?)
I would use these filters. Accept the default duration for high pass filter
and specify 'hrf' for low pass filter
> epoch length for trial 1 : 7
> (is this correct in this situation?)
Yes.
> Results button
> -> I set default value for mask, threshold and so on.
> I set t-contrast "1 -1" or "-1 1", is it correct?
> I want to z-score, which is (mean(rest)-mean(activation))/SE,
> but the different options give different z-scores.
This is what you are doing wrong I think. You specified one condition so
have two columns in the resulting design matrix. One represents the boxcar
(activation vs rest), the other is a constant term modeling the mean
activity over all conditions. Your t-contrasts are comparing these two
regressors, which will give weird results.
What you should do is use contrasts [1] or [-1] to see areas where
activation>rest, or rest>activation respectively. If you had used two
regressors to model activation and rest separately then the corresponding
contrasts would be [1 -1] and [-1 1].
Best wishes,
Geraint
--
Dr. Geraint Rees
Wellcome Advanced Fellow, Lecturer,
Division of Biology 139-74, Institute of Neurology,
California Institute of Technology, University College London,
Pasadena CA 91125 London WC1N 3BG
voice 626-395-2880 020-7833-7472
fax 626-796-8876 020-7813-1420
web http://www.klab.caltech.edu/~geraint
--
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
|