Dear Isabel
That's fine. It just means that your A-matrix will represent the baseline connectivity, and the B-matrix will add onto this. In which case, the regressor was probably mean-centred because you had orthogonalisation of parametric regressors turned on when you specified the GLM. If you don't want this, in the specify GLM batch, set 'orthogonalise modulations' to 'No'.
Let me know if that doesn't clear things up.
Best
Peter
-----Original Message-----
From: Isabel Wunder [mailto:[log in to unmask]]
Sent: 04 September 2017 12:59
To: [log in to unmask]; Zeidman, Peter <[log in to unmask]>
Subject: Re: DCM - height of parametric modulatory input
Dear Peter,
thank you very much for your quick reply.
No I did not specify central input! What does that mean for my calculations?
Cheers,
Isabel
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