Organization of aldolase C compartments and topographic olivocerebellar projection based on the five groups in the present study. A, Topographic organization explained with orientation axes. Areas belonging to each of the five groups (green, blue, yellow, red, and gray for groups I-V, respectively) were mapped on the aldolase C compartment pattern of the cerebellar cortex (left) and on the solid schemes of the inferior olive (right). Arrows with dark colors indicate the mediolateral direction in each group in the cerebellar cortex and the orientation axes in the inferior olive. The orientation axes correspond to the medial to lateral direction in the cerebellar cortex in terms of the topography of the projection. Group II has two orientation axes, corresponding to the projection to the central cortical area from the rostral and lateral subnucleus c (violet) and to the projection to the rostral and caudal cortical areas from the caudal subnucleus c, subnucleus β, DMCC, caudal dorsomedial subnucleus of the PO (DM), and caudomedial ventral lamella of the PO (v-PO) (blue). This panel is based on the data shown in Figures , , , . Group V (gray) consists of the flocculus and nodulus and a few areas in the hemisphere innervated by the DC and VLO (). B, A schematic of major inputs to the inferior olive reported so far sorted according to the groups classified in the present study. Question mark indicates that the specific inputs in those areas have not been clarified. See Discussion for details. Origins of major afferents to the inferior olive are arbitrarily colored. APP, Area parafascicularis prerubralis; DCN, dorsal column nucleus; IO, inferior olive; ND, nucleus of Darkschewitsch; NOT, nucleus of the optic tract; RN, red nucleus; SC, superior colliculus; VN, vestibular nucleus. C, Correspondence between the aldolase C-based five-group olivocerebellar organization in the present study and conventional olivocerebellar zones (zones A-D). Colors indicate the same groups as in panels A and B. I-X, Lobules I-X; a-c, sublobules a-c or subnuclei a-c; BETA, subnucleus β; c-MAO, caudal part of the MAO; CP, copula pyramidis; Cr I, crus I of ansiform lobule; Cr II, crus II of ansiform lobule; d-DAO, dorsal fold of the DAO; d-PO, dorsal lamella of the PO; DC, DC of Kooy; DM, dorsomedial subnucleus of the PO; DMCC, DMCC subnucleus; DPFL, dorsal paraflocculus; FL, flocculus; Param, paramedian lobule; r-MAO, rostral part of the MAO; Sim, simple lobule; v-DAO, ventral fold of the DAO; v-PO, ventral lamella of the PO; VPFL, ventral paraflocculus.