A nucleus of the midbrain located dorsomedially to the oculomotor nucleus. It gives rise to the visceral efferent fibers terminating in the ciliary ganglion, the axons from which innervate the ciliary muscle and the sphincter iridis of the eye.
A small group of nerve cells in the rostral portion of the nucleus of the oculomotor nerve. Efferent fibers pass to the ciliary ganglion conveying impulses destined for the intrinsic muscles of the eye.