Organization of projections from the superior colliculus to the thalamic lateral posterior nucleus in the rat.

Injections of horseradish peroxidase into the lateral posterior nucleus (LP) of the rat thalamus resulted in retrograde labeling of neurons in the superior colliculus (SC). Approximately 80% of the labeled cells occurred in the stratum opticum and 20% in the stratum griseum superficiale. The system of projections is organized such that medial parts of SC project to dorsal LP and lateral parts of SC project to ventral LP.