Figure 3.

Tractography in the left hemisphere of a single subject for areas 44 and 45. The tractography revealed that the connections (shown in green) between the large Broca area ROI (purple) and the ROI in the rostral inferior parietal lobule within the supramarginal gyrus (yellow) began mainly in area 44. In contrast, the connections (shown in red) between the large Broca area ROI and the ROI in the superior temporal gyrus and sulcus originated mainly in area 45. The colored pathways are surfaces encompassing all nonzero voxels in the connectivity map for each connection. Although the tract data displayed here are projected on a single plane, investigation using our 3D tract display demonstrated that projections from area 44 likely travel along the SLF III to the inferior parietal cortex. In contrast, the projections of area 45 traveled through the ECFS into the superior temporal gyrus and sulcus, anterior to Heschl's gyrus. This is demonstrated in the coronal sections within a single subject (a–h).