Terminal distribution of mossy fibers traversing the superior cerebellar peduncle in the mouse.

The carbocyanine membrane probe DiI was applied to cut fibers of the superior cerebellar peduncle in the fixed brains of adult mice. Labeled mossy fibers in the cerebellar cortex formed rosettes only in the most superficial aspect of the granular layer, just beneath the Purkinje cell layer. These results provide evidence for a functional division of the cerebellar granular layer into horizontal laminae, in addition to the commonly recognized lobular and sagittal divisions of the cerebellar cortex.