Cell adhesion molecule with an important role in the development of the nervous system. Involved in neuron-neuron adhesion, neurite fasciculation, outgrowth of neurites, etc. Binds to axonin on neurons (By similarity). Expressed in postmitotic neurons in 16-36 hours embryos, including those in the brain, cranial ganglia and otic and olfactory placodes, and in all classes of spinal neurons. Onset of expression correlates with the initiation of axonogenesis in 16-36 hours embryos. Belongs to the immunoglobulin superfamily. L1/neurofascin/NgCAM family.