Hi Alfonso,

thank you very much for your helpful reply. I will follow your suggestion and include the conditions as Confounds.

Just to make sure I understand: if I do _not_ do this, the "effect of X" item which is included in the list of 'sources' would correspond to a ROI defined by the "activation" of the BOLD signal in response to the effect of X, as determined by a classical GLM?

Thanks again

Nicola