How do neurofibrils differ from nerve fibers?

Neurofibrils are bundle of thin microtubules and microfilaments formed by the cell's cytoskeleton, they serve as a passage for rapid transport of molecules to and from a far end of a neuron but they do not conduct impulses while nerve fibers conduct impulses.

The two structures differ in their functions. Neurofibrils serve to transport molecules, while nerve fibers transport electrical impulses.