Abstract

The afferent fibers (mossy and climbing fibers), and the efferent fibers represented by Purkinje cell axons of the cerebellar white matter have been described by means of conventional scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) and SEM cryofracture technique, transmission electron microscopy conventional (TEM), and confocal laser scanning microscopy. At SEM level the three-dimensional characterization of mossy and climbing fibers has been made according to their thickness and branching pattern. The mossy fibers appear as thick parent fibers, up to 2.5 μm in diameter with a characteristic dichotomous bifurcation pattern. The climbing fibers are thin fibers, up to 1 μm in diameter, with a typical crossing-over bifurcation pattern. The efferent Purkinje cell axons labeled with calbindin and imaged with confocal laser scanning microscopy appear as red fibers exhibiting recurrent collateral processes.