Light Microscopy, Scanning and Transmission Electron Microscopy of Vertebrate Cerebellar Golgi Cells

The cerebellar Golgi cells of mouse, teleost fish, primate and human species have been studied by means of light and Golgi light microscopic techniques, slicing technique, ethanol-cryofracturing and freeze fracture methods for scanning electron microscopy and ultrathin sectioning for transmission electron microscopy. The Golgi cells appeared in the granular layer as polygonal, stellate, round or fusiform macroneurons surrounded by the granule cell groups. They exhibited ascending and horizontal dendrites and a short beaded axonal plexus. Scanning microscopy revealed three-dimensional neuronal geometry and smooth outer surfaces. Freeze-fracture method showed stereospatial arrangement of endoplasmic reticulum, organelles and nuclear envelope. By means of transmission electron microscopy asymmetric synaptic connections of horizontal dendrites of Golgi cells with mossy fiber rosettes at the cerebellar glomerulus and of Golgi cell axons with granule cell dendrites were identified. Golgi cell ascending dendrites exhibited short neckless spines in the molecular layer establishing asymmetric contacts with granule cell axons or parallel fibers. Shaft asymmetric axodendritic contacts between Golgi cell dendrites and climbing fibers were also found in the molecular layer.