In order to better understand Dynamic Causal Modeling I developed a while ago a small program that allows me to setup a model and to immediatly see how the neural parameters influence the hemodynamic and neural signal generated by the equations. The program is far from being complete and comfortable but I think it helps already a lot to understand the internal dynamics and how the signal generated by estimated parameters look under noise-free conditions. I don’t have time any more to continue the development on this program. But I release it here under a Creative Commons License.
The program is started with “dcm_create” which opens a window in which you can setup a new DCM.
After a click on “Create” another window opens in which you can modify the neural parameters of your model and see how the signals look like.
You can modify the parameters of the A, B and C matrix
And select whether you would like to see the hemodynamic signal (default) or the neural signal (identity).
After a click on “Update” you see the updated signal.
It is important that SPM 8 is in the search path of Matlab. The program was developed for the first SPM8 versions (e.g. spm_dcm_create.m 4310 2011-04-18) which uses the same structure and model than DCM in SPM5, before it was revised after this work.
Feel free to modify and extend the code for your purposes.