Study on afferent projections from the abducens nucleus to the contralateral medial rectus subnucleus of the oculomotor nucleus in the rat

Objective: To investigate afferent projections from the abducens nucleus to the contralateral medial rectus subnucleus of the oculomotor nucleus in rats.Methods:The means of retrograde hoseradish peroxidase tracing was used.Results:The internuclear neurons in the abducens nucleus were divided into two subgroups,the ventromedial and the ventrolateral ones. The axons of the internuclear nurons crossed the midline,ascended in the contralateral medial longitudinal fasciculus and intermediated exclusively in the contralateral medial rectus subgroups.Conclusion:The results imply that the internuclear meurons could play a major role in conjugate horizontal eye movement.