Figure 1.

Schematic of a neuron cell along with dendrites and its axon. (a) A zoomed-in view of the axon initial segment showing the bundled MTs. MT filaments, represented by helical structures of heterodimers (blue and green beads), are bundled by MAP tau crosslinks (red). Discontinuities are randomly placed along the length of the filaments. (b) A zoomed-in view of two MT filaments and one MAP tau protein, showing a detailed schematic of the bead-spring model. Bundle filaments are represented by a network of beads (blue) connected by spring elements of axial constant k^MT (dark blue). Torsional springs (white), representing bending stiffness of k_b, were also included for each MT element. Crosslinks (red) are modeled as spring elements with axial spring constant k^CL. (Not drawn to scale.) To see this figure in color, go online.