The neuropil in superficial layers of the superior colliculus of the mouse

Summary In a study of Golgi preparations of the superior colliculus of the mouse, three fundamental types of neurons are described. These are: horizontal cells located in the stratum zonale, short axon cells abundant in the stratum griseum superficiale, and long projecting neurons for which representative types are described in the stratum opticum. In the electron microscope these three types of cells are recognized. Peculiar collateral dendritic processes of horizontal cells and of some short axon cells are correlated in Golgi and electron microscope images. They are identified as vesicle-containing dendritic processes. Electron microscopy of the neuropil in the stratum griseum superficiale shows the existence of three major categories of vesicle-containing processes that have been identified as optic terminals, vesicle-filled dendritic profiles of short axon cells and terminals with small vesicles. Their synaptic relations are studied in normal preparations and in experimental animals after eye enucleation and cortical lesions.Supported by research grant from Fundación Eugenio Rodríguez Pascual.