Organelles in neuroplasmic ("axonal") flow: neurofilaments.

The electronmicroscopically conspicuous "neurofilaments" in axons manifest a marked constancy of mutual distance at all levels of a nerve fiber regardless of the wide variation of cross-sectional area along the course of a single axon or between different axons. The filaments conform to the rheological flow patterns of the axonal flow and must be viewed as discontinuous, metastable, and transitory linear assemblies of subunits present in the axonal matrix. The grid-like distribution of the filaments in the matrix suggests properties akin to those of liquid crystals of heterogeneous composition.