Hi guys,

I use tkmedit (current MGH beta release) to manually select my ROIs. I overlay the functional contrast, move the cursor inside the cluster of interest, and then go Tools/fMRI/Select contiguous voxels by threshold (after setting the threshold for a proper value of course). Works great, the volume turns green, and can be saved as a label.

But only for positive contrast values.

When I point the cursor inside a negative cluster and Select Contiguous Voxels by Threshold, nothing will turn green. Saving the label will result in a file with contents zero.

Reversing values in "Configure functional overlay" does not help.

Same problem with the alpha release.

However, selecting with "Select contiguous voxels by Func Value" can pick also negative clusters. But then it is more difficult to control the threshold of course - I would prefer to use the Threshold.

Any suggested ways around this? Or am I just doing something plain wrong?

Thanks,

Tommi

--- Tommi Raij, M.D., Ph.D. MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging Bldg 149, 13th St Charlestown, MA 02129