An anterogradely-labeled prefrontal cortico-oculomotor pathway in the monkey demonstrated with HRP gel and TMB neurohistochemistry.

Implants of horseradish peroxidase gel6 in the sulcus principalis and/or area 8 "frontal eye field" cortex of macaque and cebus monkeys, processed with tetramethyl benzidine (TMD) neurohistochemistry9, resulted in anterograde labeling of a prominent "prefrontal oculomotor bundle" which traversed the medial subthalamic region at the diencephalic-mesencephalic junction to terminate directly in accessory and principal oculomotor nuclear groups. This report provides clear evidence suggesting direct cortical involvement in ocular motility, and the location of the pathway contributes to our understanding of ophthalmoplegias resulting from lesions in the rostralmost mesencephalon.