Hi Katie,
you can use the custom fill tool in tksurfer for this. Display your activation map at whatever threshold you want, then click in the middle of the blob you want to create an ROI for and do custom fill with "up to functional threshold". This will floodfill from that point outwards stopping when it reaches vertices that are below threshold
cheers Bruce
On Fri, 1 Jul 2011, Katie Bettencourt wrote:
I'm trying to draw an ROI by selecting the center of activation for a particular contrast and then selecting nearby voxels within a certain range (for example. say 20 voxels). Ideally I'd like to select only the voxels within this range that are activated by my contrast. However, I can't see how to do this, any help would be appreciated. Thanks,
Katie