Fig. 2.

Navigability of mammalian connectomes. (A–D) Success ratio ($S_R$), binary efficiency ratio ($E_R^{bin}$), weighted efficiency ratio ($E_R^{wei}$), and distance efficiency ratio ($E_R^{dis}$) for human connectomes ($N=360$) at several connection density thresholds. Empirical measures (red) for group-averaged connectomes were compared with 1,000 rewired (green) and spatially repositioned (blue) null networks. Shading indicates 95% confidence intervals. (E) The same performance metrics shown across different parcellation resolutions of mammalian structural networks ($S_R$ shown in blue, $E_R^{wei}$ in orange, $E_R^{bin}$ in yellow, and $E_R^{dis}$ in purple). Triangles denote nonhuman species while circles denote human data. Dashed lines denote the same connection density (15%) across all human networks. (F) Navigability stratified by hop count ($N=360$ at 15% connection density). Blue box plots indicate the quartiles of $E_R^{wei}$ navigation paths benchmarked against shortest paths with matching hop count. Bar plots show the number of shortest paths for a given hop count, with colors indicating the proportion of successful (green) and failed (red) navigation paths. Brain diagrams reproduced from ref. 9, with permission from Elsevier.