Mediolateral Differential Projection to the Nodulus from the Inferior Olive in the Albino Rat: A Retrograde WGA-HRP Study

Abstract

The mediolateral topographic organization of olivocerebellar projections to the nodulus in rats was investigated by a retrograde WGA-HRP method. The nodulus received olivary afferents from the contralateral dorsal cap, nucleus β, ventrolateral outgrowth, and dorsomedial cell column. The mediolateral extent of terminal areas of the olivocerebellar fibers arising from these subnuclei differed. The dorsal cap projected to the entire mediolateral area of the contralateral nodulus; the rostral and caudal parts of the dorsal cap projected to the lateral and medial parts of the nodulus, respectively. The nucleus β projected to the medial and intermediate parts of the nodulus. Differential projections from the nucleus β were observed in a rostrocaudal direction as those from the dorsal cap; the rostral and medial parts of the nucleus projected to the intermediate and medial parts of the nodulus, respectively. The ventrolateral outgrowth projected only to the intermediate part of the nodulus. The dorsomedial cell column projected to the lateral half of the nodulus, including its lateral tip. These and previous findings are compared with respect to this mediolateral topography.