Functionally, the cerebellar cortex can be divided into three areas. The vermis in the midline influences movements along the axis of the body, including the neck, trunk, abdomen, and pelvis (eFig. 9.66). Adjacent to the vermis, the intermediate zone controls muscles of the distal upper and lower limbs. The lateral zone participates in motor planning to coordinate sequential movements of the entire body. Input to these functional areas of cerebellar cortex come from the cerebral cortex, spinal cord, and brainstem by passing predominantly through the middle and inferior cerebellar peduncles. Fibers entering the cerebellum proceed as mossy fibers (from various regions) or climbing fibers (from olivary nucleus). Mossy fibers form excitatory synapses with dendrites of the granule cells, in the granule cell layer (eFig. 9.67). From here, the granule cells send axons to the molecular layer, where they bifurcate into parallel fibers that run longitudinally in the folia. The parallel fibers then synapse on Purkinje cells in the outermost Purkinje cell layer (eFig. 9.67). Climbing fibers project to the Purkinje cell layer and form powerful excitatory connections with the Purkinje cells. The Purkinje cells then project to the deep cerebellar nuclei (eFig. 9.67).