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Hi SPMers,

I am looking at the relationship between neural activity and behavioral
performance, and was hoping for some insight for correct interpretation of
a particular analysis.

On the first level, I have a model with my fMRI signal (first column), my
behavioral performance as a parametric modulator (second column), and my 6
motion regressors. I am interested in the behavioral parametric modulator,
so I put a contrast over the second column.

When I forward these individual subject contrasts to the second level, and
do a one-sample t-test to look at group, with t-contrast [-1], I find
certain task-related regions show significance. Would it be correct to say
that the behavioral performance modulates neural activity, with
improvements in performance across time reflecting decreases in neural
activity in these certain regions?

Additionally, I conduct a 2-sample t-test, forwarding the first-level PM
contrasts to the second-level, comparing young and old subjects. Here I
find young>old gives me some interesting task-related regions. Am I correct
to say that young adults' neural activations are more closely tied to
behavioral performance than for old adults?

Thanks in advance,
Joelle