Hi RIck,
Sorry for the late reply. I thought this message board conversation had moved to an email conversation.
I populated the datasets by looking at a CT showing implanted electrodes fused to a T1 MRI scan using Brainlab software. I took the datasets to AC-PC space in Brainlab.
Then I reconstructed the dicoms in afni for the T1 MRI and took the anatomical dataset to AC-PC space. Then I visually matched where the electrode tips were in Brainlab and drew a 'dot' on that voxel in afni. Then I proceeded as previously described.
I suppose it would be fine to keep all the files (brainlab and afni) in orig space, eyeball the electrode tips, then transform them to talairach space in afni. For some reason, I thought it would be easier to eyeball the electrode tips if all the scans were in AC-PC. It seems to have caused more problems than it solved.
Christine