Dear Ahmad,
One can always consider the possibility that an experimental effect can have both driving (C)and modulatory (bilinear - B) effects at the same time. This is
not very common in most designed experiments because one usually has a driving (stimulus or task-bound factor) and a modulatory or contextual factor – for example, visual stimuli (animate vs. inanimate) could drive V1 while attention (to motion or colour)
could modulate V1 to V5 connections. However, attention could also act as a driving input to a parietal region to account for baseline shifts in V5. This would be an example where the attention factor (input) meditated its effects via both driving and bilinear
effects.
With very best wishes,
Karl
From: Ahmad
Amini [mailto:[log in to unmask]]
Sent: 18 December 2012 14:58
To: Friston, Karl
Subject: RE: [SPM] simulated data
Dear Prof. Friston
Please Let me know when I define an input for Direct input, should I consider that possibility which that input is a modulatory input simultaneously
or not.
I’ve asked of some expert DCM about my problem and they've answered that I should consider that possibility but in most your paper which I’ve
read , the input has been only a direct input or a modulatory input.
Thank you for your help in advance
All the best.
Ahmad Amini
PhD student
Institute for Analysis
and Scientific Computing
Vienna University of Technology
Austria