Title: Regenerating nerve fiber innervation of extraocular muscles and motor functional changes following oculomotor nerve injuries at different sites Author(s): Zhang Wenchuan; Visocchi Massimiliano; Fernandez Eduardo NEURAL REGENERATION RESEARCH Volume: 6 Issue: 26 Pages: 2032-2036 DOI: 10.3969/j.issn.1673-5374.2011.26.006 Published: SEP 15 2011 In the present study, the oculomotor nerves were sectioned at the proximal (subtentorial) and distal (superior orbital fissure) ends and repaired. After 24 weeks, vestibulo-ocular reflex evaluation confirmed that the regenerating nerve fibers following oculomotor nerve injury in the superior orbital fissure had a high level of specificity for innervating extraocular muscles. The level of functional recovery of extraocular muscles in rats in the superior orbital fissure injury group was remarkably superior over that in rats undergoing oculomotor nerve injuries at the proximal end (subtentorium). Horseradish peroxidase retrograde tracing through the right superior rectus muscle showed that the distribution of neurons in the nucleus of the oculomotor nerve was directly associated with the injury site, and that crude fibers were badly damaged. The closer the site of injury of the oculomotor nerve was to the extraocular muscle, the better the recovery of neurological function was. The mechanism may be associated with the aberrant number of regenerated nerve fibers passing through the injury site.