Mapping of labeled climbing fibers and summarized topographic scheme of the olivocerebellar projection belonging to group II. This group consisted of projections from subnucleus c of the caudal part of the MAO (c-MAO) to a+//2+, c+//4b+, and d+//5a+; from subnucleus β (BETA) to a+//2+; and from the DMCC, caudal dorsomedial subnucleus of the PO (DM), and caudomedial ventral lamella of the PO (v-PO) to 2b+//4+. A, Plots of climbing fibers in eight injections terminating in a+//2+ labeled with injections into the subnucleus β and caudal subnucleus c of the c-MAO. Two injections (red and light green) were spread to both the c-MAO and subnucleus β. B, Plots of climbing fibers in five injections terminating in a+//2+, c+//4b+, and d+//5a+ and retrogradely labeled olivary neurons in three experiments (yellow green, green, and purple). Plots of injection sites and retrogradely labeled neurons in the inferior olive were classified into medial and lateral ones and drawn separately to improve visibility. The yellow injection was spread to the subnucleus β, presumably explaining the labeled climbing fibers in lobules VIII-IX in this case. C, Plots of climbing fibers in five injections terminating in 2b+//4+ and retrogradely labeled olivary neurons in two experiments (light blue and purple circles). Labeled climbing fibers in each anterograde labeling experiment (A, B) were nearly aligned in a single narrow band in a pair of linked rostral and caudal aldolase C compartments with few, if any, outside climbing fibers, except for a few cases (A, blue and light blue; B, blue) in which climbing fibers were distributed in multiple compartments. D, Putative olivocerebellar topography within group II.