Fig. 4. Central connections of the horizontal and anterior semicircular canals mediating angular vestibulo-ocular reflex. Primary afferents of the horizontal semicircular canal (HC) project to the medial vestibular nucleus (MVN). Neurons in the medial vestibular nucleus project across the midline to terminate in the VIth nerve nucleus. Two types of neurons are in the VIth nerve nucleus, abducens neurons that project to the lateral rectus (LR) muscle, and interneurons that cross the midline and travel up the medial longitudinal fasciculus (MLF) to innervate the medial rectus subnuclei of the IIIrd nerve nucleus. Primary afferents of the anterior semicircular canal (AC) project to the lateral vestibular nucleus (LVN) and MVN, which in turn project across the midline and travel up the MLF to terminate in the superior rectus and inferior oblique subnuclei of the IIIrd nerve nucleus.