Basal interstitial nucleus

Fig. JOS. The cerebellar nuclei of Macaco fascicularis. Upper diagram is a graphical reconstruction of the cerebellar nuclei in a dorsal view. Levels of the transverse sections are indicated. The U-shaped, transitional nucleus located between the fastigial (F) and posterior inter-posed nucleus (IP) is indicated with double hatching, be = brachium conjunctivum BIN = basal interstitial nucleus of Langer cr = restiform body DV = descending vestibular nucleus F = fastigial nucleus lA = anterior interposed nucleus IP = posterior interposed nucleus L = lateral cerebellar nucleus LV = lateral vestibular nucleus (Deiters ) MV = medial vestibular nuleus SV = superior vestibular nucleus Y = group y asterisk = medial one-third of the brachium conjunctivum.

One group of small neurons in the rhesus monkey, which was described by Langer (1985) under the name of the basal interstitial nucleus (see Section 5.1.), displays uniform and strong AChE activity. These small cells lie dispersed in the white matter of the flocculus and the nodulus and ventral to the dentate and the posterior interposed nucleus, in the roof of the fourth ventricle. The presence of strongly AChE-positive but ChAT-negative small cells in the white matter of the flocculus of the rat, that may correspond to Langer s interstitial nucleus, was noticed by Komei et al. (1983). 

The white matter compartments of the flocculus do not simply continue as components of the floccular peduncle, but a reorganization takes place, that directs Purkinje cell axons from the compartments 2 and 4 to the medial vestibular nucleus and of the compartments 1 and 3 to the superior vestibular nucleus. The C2 compartment does not contribute to the floccular peduncle, but leads its fibers towards the posterior interposed nucleus. In monkeys the equivalent of compartment 1 of the rabbit extends in the roof of the fourth ventricle, along the basal interstitial nucleus of the cerebellum (Fig. 148). 

Fig. 148. Compartmentation in AChE-stained transverse sections of the flocculus, the ventral paraflocculus and the petrosal lobule and the caudal hemisphere of Saimiri sciureus. Note AChE stained borders of the compartments and the differential staining in the molecular layer AChE-positive cells of the basal interstitial nucleus of Langer are located along the borders of the compartments C2, 1 and 2 in (D) and (E). Group y is located within the floccular peduncle in (E), ANS = ansiform lobule br.p = brachium pontis c.rest = restiform body Cl-3 = C21-3 compartments D = dentate nucleus Dl,2 = Dl,2 compartments F = fastgial nucleus fis.post.lat = posterolateral fissure FLOC = flocculus lA = anterior interposed nucleus IP = posterior interposed nucleus Ib.petr = petrosal lobule PFLD = dorsal paraflocculus PFLV = ventral paraflocculus. Courtesy of Dr. D.T. Hess.

Langer TP (1985) Basal interstitial nucleus of the cerebellum cerebellar nucleus related to the flocculus. J. Comp Neurol, 235, 38 7. 

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