Figure 5.

Identification of the regions of constrained diffusion. (A) Distribution of measured Φ(r₀) values for the case of isotropic diffusion (upper) and constrained diffusion (lower) presented in Fig. 4. (B) Scatter plot of the measured Φ(r₀), $D_{\text{avg}}^{\ast }\left({\mathbf{r}}_0\right)$ pairs for the case of isotropic diffusion (blue dots) and diffusion with barriers (red dots). The presence of barriers leads to a more dispersed distribution characterized by lower $D_{\text{avg}}^{\ast }\left({\mathbf{r}}_0\right)$ and higher Φ(r₀) values. (C) The points corresponding to the Φ(r₀), $D_{\text{avg}}^{\ast }\left({\mathbf{r}}_0\right)$ pairs in the boxed region in (B) are highlighted in red and identify the region of constrained diffusion. The position of the barriers is readily deduced, thus demonstrating that the diffusion tensor is able to unveil the localization of anisotropic diffusion areas. Scale bar, 500 nm. To see this figure in color, go online.