Figure 4.

(a) Dimensionless concentration of free cytosolic tau, $n_{\mathrm{free}}=n_{\mathrm{free}}^{\ast }/n_{\mathrm{tot},x=0}^{\ast }$, versus position in the axon. Free tau can polymerize and be converted to the misfolded tau, see equation (2.6). (b) Percentage of MT-bound tau, defined by equation (2.10), versus position in the axon. Modelling results without tau agglomeration and with tau agglomeration are shown to validate the QSSA for computing distributions of tau concentrations in various kinetic states along the axon. Results with tau agglomeration are shown at the time when n_mis(x*) reaches its steady-state distribution. (Online version in colour.)