Dear Jack,
> |5- The way I figure it could only be name functional connectivity, not
> |effective, since no model is imposed. True ? Thus to do effective connec
> |tivity, one should plot the intensity of one voxel against the one of
> |another that have to be specified (another activated regions for example).
>
> I would defer to others on the subject of effective connectivity. My
> understanding is that by imposing a model, an analysis of effective
> connectivity allows an estimation of the relative contribution of multiple
> other ROIs to evoked activity in a voxel of interest. In the analyses
> discussed here, only the contribution of a single physiological source of
> activity (in ROI X) is considered.
Geraint is absolutely right. However you could think about a design
matrix in which the time-series of multiple voxels is used. This would
then allow the contribution of multiple areas on certain target areas
and therefore enter the area of effective connectivity. If you would
further consider non-linear effects (and temporal memory) amongst those
areas this would conceptually lead to the idea of Volterra-kernels.
-Christian
--
Dr. C. Buechel
Research Fellow
Functional Imaging Laboratory
Wellcome Dept. of Cognitive Neurology
12 Queen Square
WC1N 3BG London
UK
Tel.: +44-171-833-7483
Fax.: +44-171-813-1420
email: [log in to unmask]
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