Peripheral and Central Organization of the Extraocular Muscle Proprioception in the Ungulata

Abstract

Publisher Summary This chapter presents the results obtained in investigations carried out in laboratories and analyzes the peripheral and central course of the proprioceptive afferents from the eye muscles in the ungulata. On the basis of histological and electrophysiological investigations the first-order neurons of the extraocular muscle proprioception have been localized in the medial dorsolateral portion of the semilunar ganglion. While the peripheral process attains the eye muscle proprioceptors, the central one enters the brain stem through the sensory trigeminal root and terminates ipsilaterally in the oral portion of the spinal trigeminal nucleus and in the main sensory trigeminal nucleus. Such nuclei contain the second-order neurons of the eye muscle proprioception which project on the cerebellum and on the mesodiencephalic areas. Axons reach the ipsilateral ventrobasal nuclear complex of the thalamus through the ipsilateral medial lemniscus and the dorsal trigeminothalamic tract. Collaterals are abandoned in the tectum and in the tegmentum of the mesencephalon. A somatotopic arrangement of the eye muscle proprioception has been found in the semilunar ganglion, in the pontine trigeminal nuclei and in the mesencephalon.