Figure 2.

Olivocerebellar modules in mammals. The three-element modules of the olivocerebellar system are formed by a sagittal strip of Purkinje cells in the cerebellar cortex (A), which converge onto a particular set of cerebellar and/or vestibular nuclei (B–D), which, in turn, innervate the subnucleus in the inferior olive (E,F) that provides the climbing fibers to the corresponding strip of Purkinje cells, forming a closed triangular loop. (A) The left part of the cerebellar cortex indicates the original zones described by Voogd (1964), whereas the right part indicates the zebrin related groups described by Sugihara (2011). The color coding used in panels B–F is the same as that used for describing Sugihara’s groups in A (i.e., right half), and together they reflect which parts within a particular olivocerebellar module are connected. For reference, we indicated the zebrin-positive strips with dark shading in Voogd’s zones on the left. (A) 1–6(a/b/–/+) (see Sugihara and Shinoda 2004, 2007); I–X, lobules I–X; CP, copula pyramidis; Cr I/II, crus I/II of ansiform lobule; FL, flocculus; Par, paramedian lobule; PFL, paraflocculus; Sim, lobulus simplex. (B,C) AICG, anterior interstitial cell group; AIN, anterior interposed nucleus; CP, copula pyramidis; DLH, dorsolateral hump; DLP, dorsolateral protuberance; DMC, dorsomedial crest; (v)DN, (ventral) dentate nucleus; FN, fastigial nucleus; ICG, interstitial cell group; PIN, posterior interposed nucleus. (D) DVN, descending vestibular nucleus; dY, dorsal group Y; MVN, medial vestibular nucleus; PrH, prepositus hypoglossal nucleus; SVN, superior vestibular nucleus. (E,F) β, subnucleus β; (c/v)DAO, (central/ventral) dorsal accessory olive; dc, dorsal cap; DM, dorsomedial group; DMCC, dorsomedial cell column; MAO, medial accessory olive; (d/v)PO, (dorsal/ventral) principal olive; VLO, ventrolateral outgrowth. Note that the X/CX-zones have only been found at the electrophysiological level (Ekerot and Larson 1982).