Convergence of the descending pathways of motor, visual and limbic cortex in the cat di- and mesencephalon.

Comparisons of the descending pathways of the motor, visual and limbic cortex in the cat revealed a number of structures in di- and mesencephalon that receive projections from all these fields. They are centrolateral (CL), paracentral (Pc), central medial (CeM) and centre median (CM), nuclei of the thalamus, zona incerta (ZI) and Forel's field H1 of the subthalamus, nucleus of the posterior commissure and anterior and posterior nuclei of the pretectum (Prt), stratum griseum intermedial and profundum of superior colliculus (CS), periaqueductal gray matter (GC) and pontine nuclei (NP). The projections from the striate field of the visual cortex to ventrobasal complex of the thalamus (VB) are shown. The results are discussed with recent data on the anatomy and physiology. A possible role of corticocortical and corticofugal fiber connections is dealt with.