Preganglionic nerve fibers

In the autonomic nervous system, fibres from the CNS to the ganglion are known as preganglionic fibers. All preganglionic fibers, whether they are in the sympathetic division or in the parasympathetic division, are cholinergic (that is, these fibers use acetylcholine as their neurotransmitter) and can be either unmyelinated or myelinated.