Fig. 6.

R1 vs. position along trajectories through high R1 regions on Heschl’s gyrus. (A) View of the superior temporal lobe showing the approximate orientation of the trajectories (green arrows). The actual trajectories followed the cortical surface. Red and blue lines indicate the antero-medial and posterolateral edges (respectively) of the high R1 regions on Heschl’s gyrus. (B) R1 vs. position (i.e., surface vertex number) averaged across hemispheres and trajectories (four trajectories per hemisphere, each located at a different position along the length of Heschl’s gyrus). Data from the three hemispheres with potentially less accurate segmentation (to right of dashed line in Fig. 5) were not included. Prior to averaging, individual trajectories for the left panel in B were aligned relative to the posterolateral edge of the high R1 region (blue line). Individual trajectories for the right panel in B were aligned relative to the antero-medial edge (red line). The horizontal axes are colored green to highlight the fact that they correspond to the postero-lateral (B, left) and antero-medial (B, right) trajectories schematized in panel A. Gray background shading indicates that the plotted data lie outside the region of high R1 as defined by the thresholding procedure (see Methods). Each hemisphere was considered a data point in calculating the standard error of the mean (shading indicates ± one SEM). The spacing between vertices is approximately 1 mm. Note that the edges of the high R1 region (red and blue vertical lines in panel B) coincide with the sharpest spatial change in R1.