Figure 5.

Tonotopic field sign maps. A, For left and right hemisphere (top and bottom row, respectively), the anatomy is shown as an inflated mesh. The narrowly tuned regions (i.e., high values in the maps of tuning width) in left and right hemisphere are outlined in black, showing that the main axis of these narrow regions is oriented along the main axis of HG. B, Group tonotopic maps as extracted from natural sounds (also displayed in Fig. 2B). The black outline shows the narrowly tuned region. C, Field sign maps based on the tonotopic maps shown in B. Blue and green colors indicate low-to-high and high-to-low tonotopic gradients with respect to the reference axis (i.e., the main axis of the narrowly tuned region, outlined in black), respectively. The reversal of the field sign defines the border between tonotopic maps (e.g., border between hA1 and hR). The reference axis is displayed by the black arrow in the circular blue-green color legend, and the main anatomical axis of HG is shown in white. The triangle indicates an additional frequency reversal at the medial convergence of HG and HS.