Dear all,
I don't think that this question has been addressed before:
I would like to set up a DCM analysis with fMRI data to investigate the
following issue: we have identified an activation in a very well known network
of 4 brain regions (A,B,C,D), and we believe that, in our task, this network can
be gated - depending on which one of 2 different input modalities is involved -
by the activity of two other distinct networks, each including 3 brain regions
(E,F,G, or H,I,J).
That is, we would like to assess how network EFG interacts with network ABCD in
modality 1 and how network HIJ interacts with network ABDC in modality 2, in the
context of a sort of 2x2 (Modality x network-network interaction) factorial design.
I presume that one could address this, by simply treating each brain region
independently, and for instance by using BMS to test whether the preferred model
fits the expected interaction patterns, but I think that there may be problems
with the relatively large number of regions (>8).
I also presume that the question could be approached by non-linear DCM, even
though I think that non-linear DCM has been only used in the context of the
influence of one single region on a system of interconnected regions, and not in
the context of network-network interactions.
Can anyone suggest a more direct way to approach this issue?
Thank you and all the best,
Marco
--
Marco Tettamanti, Ph.D.
San Raffaele Scientific Institute
Via Olgettina 58
I-20132 Milano, Italy
Tel. ++39-02-26434888
Fax ++39-02-26434892
Email: [log in to unmask]
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