Fastigial nucleus

Fig. 103. The cerebellar nuclei of the cat. The transitional U-shaped region of the fastigial and posterior interposed nuclei is indicated by double hatching, be = brachium conjunctivum cr = restiform body DV = descending vestibular nucleus F = fastigial nucleus flo = floccular peduncle Ftail = tail of the fastigial nucleus lA = anterior interposed nucleus IP = posterior interposed nucleus L = lateral cerebellar nucleus LV = lateral vestibular nucleus MV = medial vestibular nucleus SV = superior vestibular nucleus u = uncinate tract Y = group y of Brodal and Pompeiano (1957).

Fig. 104. Two transverse, AChE-incubated sections through the cerebellar nuclei of the cat, A. Rostral section. B. Caudal section. Note medium-sized cells of dorsal group y in floccular peduncle and strongly AChE positive ventral group y along dorsal border of restiform body in (A) U-shaped nucleus between IP and F in (B). cr = restiform body F = fastigial nucleus flo-i-y = floccular peduncle with group y lA = anterior interposed nucleus IP = posterior interposed nucleus IP/F = U-shaped nucleus between F and IP L = lateral cerebellar nucleus sad = stria acoustica dorsalis.

Large cells are prominent in the rostral part of the medial nucleus, small cells predominate in its ventromedial and caudal parts (Flood and Jansen, 1961). The lateral border of the medial nucleus is flush with the AChE-positive raphe which forms the lateral border of the medial A-compartment of the anterior vermis. AChE is concentrated in the lateral and ventral parts of the medial nucleus and in the neuropil of cell groups scattered in between the medial and the anterior interposed nucleus. Caudally these AChE-positive clusters coalesce in a U-shaped nucleus located at the transition of the medial and the posterior interposed nucleus (Fig. 104B). The medial limb of the U forms the lateral border zone of the fastigial nucleus, the lateral limb usually is included with... 

The posterior interposed nucleus is best distinguished in horizontal sections. A cell-free zone separates it from the anterior interposed and lateral nuclei. Medially the posterior interposed nucleus is continuous with the fastigial nucleus. Cells at the junction of these two nuclei project to the spinal cord (Matsushita and Hosoya, 1978 and Bentivoglio and Kuypers, 1982). This region was distinguished as the interstitial cell group, the target nucleus of the X zone, by Buisseret-Delmas et al. (1993). 

According to Tolbert et al. (1978a) the nucleo-olivary neurons in the cat are concentrated in the ventral parts of the dentate and posterior interposed nuclei, they are scarce in the fastigial nucleus. Concentrations of these small neurons were also reported in the rostral and caudal poles and the hilar portion of the dentate nucleus and the lateral parts of the interposed nucleus in the rat (Brown et al., 1977 Chan-Palay, 1977). A more diffuse distribution of these cells was noticed in experiments with retrograde tracing of Martin et al. (1976) in the dentate and interposed nuclei of the opossum and in double labelling studies with fluorescent dyes in rat (Bentivoglio and Kuypers, 1982) and cat (Bharos et al., 1981). 

Zebrin-immunoreactive and non-immunoreactive Purkinje cells are distributed in parallel longitudinal bands in the cortex of rat cerebellum (Hawkes et al., 1985) and distribute their axons to different parts of the cerebellar nuclei (Hawkes and Leclerc, 1986). Light microscopical observations showed that all Zebrin positive boutons on the soma and dendrites of large central nuclear cells contained GAD, and that most GAD-positive boutons on individual cells either were Zebrin-positive or -negative. The two populations of Purkinje cells, therefore, terminate on different central nuclear cells. Zebrin-positive Purkinje cells of the vermis projected to the caudal part and a majority of Zebrin-negative Purkinje cells to the rostral part of the fastigial nucleus of the rat. 

Fig. 114. EM autoradiogram of a spiny dendrite in the fastigial nucleus of the cat. A labelled mossy fiber terminal, originating from an injection of tritiated leucine into the nucleus reticularis tegmenti pontis, is densely filled with uniform spherical vesicles. Boutons with flattened vesicles form synaptic contacts on the same dendrite. Cat. Van der Want et al. (1987).

Fig, 115. EM autoradiogram showing two climbing fiber boutons with spherical and pleomorphic vesicles, labelled from an injection with tritated leucine into the inferior olive make synaptic contact with a dendrite of a neuron of the fastigial nucleus of the cat. Van der Want and Voogd (1987). 

Fig. 116. Transverse sections through the deep cerebellar nuclei of the opossum showing the position of cholecystokinin-like immunoreactive neurons in the cerebellar nuclei (dots). Such neurons are present in the nucleus interpositus posterior (NIP) and fastigial nucleus (FN), but are not present in the nucleus interpositus anterior (NIA) or dentate nucleus (DN). Bar = 1 mm. King and Bishop (1990)...

Rg. 117. Localization of serotonin-like immunoreactivity in transverse sections through the cerebellar nuclei of the opossum. DN = dentate nucleus FN = fastigial nucleus IPA = anterior interposed nucleus IPP = posterior interposed nucleus. Bishop et al. (1985). 

Fig. 123. Diagram of the corticonuclear projection in the cat. Based on retrograde labelling of Purkinje cells and their axons after injections of HRP in their target nuclei. A = A zone A = Anterior interposed nucleus ANS = ansiform lobule B = B zone C1-C3 = C1-C3 zones CRII = crus II of the ansiform lobule D1-D2 = D1-D2 zones DV = descendng vestibular nucleus F = fastigial nucleus FLOC = flocculus IP = posterior interposed nucleus L = lateral eerebellar nucleus LOB POST = posterior lobe LOB ANT = anterior lobe LV = Deiters nucleus MVmc = magnocellular medial vestibular nucleus MVpc = parvicellular medial vestibular nucleus PFL = paraflocculus PFLD = dorsal paraflocculus PFLV = ventral paraflocculus PMED = paramedian lobule SV = superior vestibular nucleus I-X = lobules I-X. Bigare (1980).

Fig. 124. Comparison of bands of AChE reaction product in the molecular layer of the anterior vermis of cat cerebellum and retrograde labelling of Purkinje cells in B and lateral A zones after an injection of HRP in the vestibular nuclei (A-C) and in the B and X zones after an injection in the lateral fastigial nucleus and the B compartment (D-F). Note different size of Purkinje cells in B and X zones. A = A zone B = B zone Deit = Deiters nucleus DV = descending vestibular nucleus F = fastigial nucleus lA = anterior interposed nucleus MV = medial vestibular nucleus X = X zone. I-V = lobules I-V. Voogd (1989).

Fig. 125. White matter compartments Cj, D, and D2 in the paraflocculus of the cat in transverse, AChE-reacted sections. Note concentric arrangement of the compartments in the dorsal and the ventral paraflocculus. A = caudalmost section D = rostralmost section. ANS = ansiform lobule brp = brachium pontis Cl-3 = Cl-3 compartments crest = restiform body D = dentate nucleus D (1,2) = D (1,2) compartments F = fastigial nucleus FLO = flocculus lA = anterior interposed nucleus IP = posterior interposed nucleus PFLD = dorsal paraflocculus PFLV = ventral paraflocculus PMD = paramedian lobule.

Fig. 129. Schematic drawing of the distribution of motilin-immunoreactive (M-i) Purkinje cells (open triangles) and glutamic acid decarboxylase-immunoreactive (GAD-i) Purkinje cells (filled circles) in a coronal section of rat cerebellum. M-i cells and GAD-i cells are both more concentrated in the flocculus and the paraflocculus than elsewhere. Both cell types occur in the vermis and participate in the formation of the sagittal microzones (arrows). M-i terminal axon projections in the deep cerebellar nuclei are heaviest in the dentate (D left side) and GAD-i projections are heaviest in the lateral vestibular nucleus (LV right side). 1 = interposed nucleus F = fastigial nucleus. Chan-Palay et al. (1981).

Fig. 142, Lateral extension of zone A in the posterior lobe with its projection to the dorsolateral protuberance (dip) of the fastigial nucleus in the rat. The cumulative results of 8 injections of WGA-HRP in the posterior lobe are illustrated. The injection sites are represented as grey areas in B and the corresponding afferent and efferent connections are represented in black in A (inferior olive) and C (cerebellar nuclei), respectively. Dots indicate single labelled neurones in A and few sparsely labelled terminals in C. The lateral extension of the A zone receives a projection from the medial subnucleus c of the caudal medial accessory olive (MAO A2-7). Buisseret-Delmas (1988a)...

Two strips of Purkinje cells were distinguished by Umetani and Tabuchi (1988) in the vermis of lobule VIII (Fig. 153). The medial zone projected to both subdivisions of the fastigial nucleus, the second zone to the posterior interposed and lateral vestibular nuclei. This region, therefore, may include equivalents of the X and B zones of the anterior lobe. It was bordered on its lateral side by the Ci zone. 

The zonal organization of the lobules IX and X was analysed by Bernard (1987) and Tabuchi et al. (1989) in the rat. According to Bernard (1987) the zonal arrangement in lobule IX is very similar to the pattern in cat and rabbit with a medial zone projecting to the fastigial nucleus and a middle zone connected with medial portions of the interposed nuclei, corresponding with the posterior interposed nucleus. The most lateral zone... 

Fig. 150. Diagram of the afferent olivocerebellar projection according to Katayama and Nisimaru (1988) and the efferent projection of the zones of the nodulus to the vestibular and cerebellar nuclei according to Wylie et al. (1994) in the rabbit. P = group 8 of the medial accessory olive DC = dorsal cap of Kooy F = fastigial nucleus IP = posterior interposed nucleus MV = medial vestibular nucleus P cell = Purkinje cell SV = superior vestibular nucleus VLO = ventrolateral outgrowth I-VI = zones of rabbit nodulus, numbered according to Katayama and Nisimaru (1988).

Fig. 180. Schematic illustration of the result of D-[ H]aspartate injection into lobules IV and V of the cerebellum of the rat. In the sketches of the cerebellar sections, retrogradely labelled axons and axon collaterals are indicated by lines and dots. Filled dots in the olives indicate the location of labelled cells. Retrograde labelling in cells of the inferior olive is also illustrated in more detail in the diagrams on the right. BP = brachium pontis DAO = dorsal acessory olive DN = Deiters nucleus FN = fastigial nucleus LL = lateral lemniscus LLV = ventral nucleus of the lateral lemniscusw MAO = medial accessory olive OI = inferior olive OS = superior olive PN = pontine nuclei PO = principal olive RB = restiform body I-X lobules I-X. Wiklund et al. (1984).

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