Figure 4.

Values of directional ratio (color-coded) computed at various discrete scales; from left to right: $a=2^{-4}{2}^{\frac{1}{4}}$, $a=2^{-3}{2}^{\frac{1}{4}}$, and $a=2^{-1}{2}^{\frac{1}{4}}$ according to the conventions of this paper. Using the convention of the discrete shearlet transform, from left to right we show the directional ratio at two, three and five scales below the resolution level of the original. As the scale becomes coarser, the values of the directional ratio in the interior of neurites become consistently more uniform and do not exceed a certain low threshold, whose existence is predicted by Theorem 3.2. In the interior of the soma and of thicker neurites, the values of directional ratio vary wildly, once again as predicted by Theorem 3.2.