FIG. 3.

Montage of probabilistic tractography data from representative cases. Probabilistic streamlines are shown for the lateral forebrain bundle (LFB), superolateral medial forebrain bundle (slMFB), fornix, and cingulum bundle in the axial, coronal, and sagittal planes. Voxels are color coded according to the number of streamlines passing through, with yellow indicating higher numbers and red indicating fewer. Streamline thresholding (i.e., minimum and maximum number displayed) was adjusted to optimize visualization of the pathways of interest. In the LFB analysis, the turquoise arrows indicate LFB streamlines connecting with the amygdala (semitransparent blue target region of interest [ROI]). In the slMFB analysis, streamlines connect with the insula (semitransparent green ROI). In the fornix analysis, the pink arrows indicate fornix streamlines connecting with the amygdala (axial and coronal images) and hippocampus (sagittal image). In the cingulum bundle analysis, the green arrows indicate cingulum streamlines connecting with the hippocampus (semitransparent turquoise, axial and coronal images) and the entorhinal cortex (sagittal image). All streamlines are propagated from the caudal raphe seed ROI to demonstrate long-range connectivity between the caudal medulla and forebrain targets.