Dear SPM users,
I am attempting PPI in SPM5. After selecting my VOI, then selecting
'psychophysiological interactions', i get the hemodynamic and neuronal
responses, [convolved] psych.variable, and PPI as I should, but also the
following message:
Warning: Matrix is close to singular or badly scaled.
Results may be inaccurate. RCOND = 1.266417e-20.
> In spm_PEB>spm_inv at 371
In spm_PEB at 244
In spm_peb_ppi at 325
the RCOND value stays the same no matter what effects of interest or
regressors are in the model, the VOIs selected, or subject being processed.
Could this possibly be a bug or am I doing something incorrect?
Would greatly appreciate assistance.
thanks,
Hemu
Emory University
Dept. Psychiatry
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