Table 1.

A list of model variables.

symbol	definition	unit
$n_{\mathrm{a}}^{\ast }$	concentration of on-track tau moving along MTs anterogradely, propelled by molecular motors	μm−1
$n_{\mathrm{r}}^{\ast }$	concentration of on-track tau moving along MTs retrogradely, propelled by molecular motors	μm−1
$n_{\mathrm{a}0}^{\ast }$	concentration of pausing on-track tau that is still associated with molecular motors and can resume its anterograde motion	μm−1
$n_{\mathrm{r}0}^{\ast }$	concentration of pausing on-track tau that is still associated with molecular motors and can resume its retrograde motion	μm−1
$n_{\mathrm{free}}^{\ast }$	concentration of free (off-track) tau in the cytosol	μm−1
$n_{\mathrm{st}}^{\ast }$	concentration of stationary tau bound to MTs, no association with motors	μm−1
$n_{\mathrm{dif}}^{\ast }$	concentration of tau diffusing along MTs, no association with motors	μm−1
t*a	time	s
x*	Cartesian coordinate along the axon	μm

^aNote that, as the equations are solved for a steady-state situation, time is not involved.