The Arrangement of Corpus Geniculatum Laterale Connections with Oculomotor Structures

The primary visual centres are known to be involved in the organisation of oculomotor acts, but the pathways of signal transmission from corpus geniculatum laterale (lateral geniculate nucleus, LGN) to the structures of the oculomotor system remain unknown. The aim of this study on 30 cats was to determine autoradiographically all the possible pathways of visual information transmission from both dorsal and ventral nuclei of the LGN to oculomotor nuclei.

It was found that there were no direct connections of the LGN with the oculomotor nucleus. The connection occurs either through the cortex or through the preoculomotor formations. These pathways are the following: (1) from the dorsal and ventral nuclei of the LGN to the visual pretectum (olivary pretectal nucleus, posterior pretectal nucleus, nucleus of the optic tract) and then to the vegetative part of III nucleus or through nucleus commissurae posterioris, Cajal and Darkschewitsch nuclei to the somatis part of III nucleus and along the medial longitudinal fasciculus to IV nucleus and periabducens region; (2) from the ventral LGN into the deep layers (IV and VI) of the superior colliculus, and then to the Edinger - Westphal nucleus, preoculomotor central gray substance, and VI nucleus; (3) from the dorsal LGN into the deep layers (IV and VI) of the superior colliculus with relay synapses in the parietal cortex and zona insecta; (4) from the dorsal and ventral nuclei of the LGN to nucleus pontis dorsolateralis and paramedianus, being connected with the vermis anterior lobe (V - VII lobes) of cerebellum, and then to nucleus vestibularis inferior and nucleus vestibularis lateralis.