Good afternoon
I have data from an N-back working memory paradigm.
There were no rest periods, but there were 3 conditions: 0back, 1back, &
2back), the first of which was modelled implicitly.
I had been thinking of the data in terms of a parametric analysis, but it
seems from the archives that this may not be necessary and that I may be
able to get the information I want from my pre-existing categorical
analyses.
I think the only advantage of applying a parametric analysis in my situation
would be to save one degree of freedom.
Do any of you think that a parametric analysis would still be the best
option for me to pursue?
The 3 things I want to know are
- which regions are just on/off? (I have this information from my
categorical analyses)
- in which regions does activity increase linearly as a function of working
memory load?
- are there any regions in which activity increase non-linearly as a
function of working memory load (a U-shaped relationship)?
I believe from the archives that I can derive information for the 2nd and
3rd questions from the standard models I already have.
My question is therefore how do I test for the last two effects in the
contrasts (NB 0back condition modelled implicitly)?
Do I actually need to generate new models in which the N-back condition is
modelled explicitly?
Your insight on this would be much appreciated.
Rachel
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Dr Rachel L. C. Mitchell.
Lecturer in Cognitive Psychology, University of Reading.
Honorary Research Fellow, Institute of Psychiatry.
Research Psychologist, Berkshire Healthcare NHS Trust.
Correspondence Address:
School of Psychology and Clinical Language Sciences,
Whiteknights Road
University of Reading
Reading
Berkshire
RG6 6AL
Tel: +44 (0)118 378 8523
Direct Dial: +44 (0)118 378 7530
Fax: +44 (0)118 378 6715
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