High voltage electron microscopy (HVEM) stereo images of whole mounted cells have revealed that the cytoplasmic ground substance comprises a three-dimensional lattice of slender strands from 4 to 10 nm dia. (termed microtrabeculae). The lattice, in effect, forms an integral cytoskeletal component that cross-links other filamentous elements to function in one fashion or another as a framework for the maintenance of cell anisometry. In Neuroblastoma, the lattice emerges from the subplasmalemmal surfaces as one of the main cytoskeletal elements involved in growth cone formation and axonal elongation. Most importantly, the microtrabeculae cross-link axonal microtubules in parallel arrays to form linear channels that direct the bidirectional flow of particles from the cell soma to the growth cone. The microtrabeculae (3–7 nm dia.) also seem to interconnect particles (lipid, lysosomal, vesicular, mitochondrial) with microtubules to facilitate their translocation. In time lapse studies, the particles in nearby channels are seen to move simultaneously by linear saltations in opposite directions, and often to reverse their direction of motion in subsequent saltations. This suggests that microtrabeculae behave as nonstatic structures capable of constantly changing, and displaying localized contractions and extensions which result in particle transport through the lattice. Further, the apparently non-ordered process of particle motion suggests that highly localized cellular control mechanisms exist to regulate lattice structure and function within individual microtubule channels. We have investigated how changes in divalent cation ratios ( Ca 2+Mg 2+) affect both lattice organizational properties and the saltation of particles along microtubule channels. Based on these studies, possible mechanisms controlling the behavior of nerve cells in general are discussed.