Vermis caudal

IX of the caudal vermis and low activity in the hemisphere, was described by Mufson et al. (1991) for primates and man. The administration of colchicine results in the expression of NGF-R in most cerebellar Purkinje cells (Pioro and Cuello, 1988, 1990 Pioro et al, 1991). Koh et al. (1989) and Fusco et al. (1991) found NGF-R mRNA expression and NGF-R immunoreactivity in adult rats to be present in alternating Purkinje cell zones of strong and weak activity (Fig. 38C,D). This zonal pattern was also observed by Pioro and Cuello (1990). Its correspondence to the pattern of mabQ113 (Zebrin) immunoreactive zones (Hawkes and Leclerc, 1987) was noticed by Sotelo and Wassef (1991) and verified by Dusart et al. (1994) in adult rats. Lesions of the white matter, or knife cuts isolating the dorsal portion of the vermis of the rat cerebellum induces NGF-R immunoreactivity in previously unstained Purkinje cells (Martinez-Murillo et al., 1993 Dusart et al., 1994). 

Fig. 69. A. Monoclonal antibody Rat-302 recognizes a subset of neurons, later identified as unipolar brush cells, restricted to the granular layer of the flocculus and the vermis of rat cerebellum (arrows), whereas in other areas of the cerebellum no positive cells are found. B. In contrast, antibody Rat-303 recognizes Golgi-II cells in the granular layer (g) in the entire cerebellum. C. Rat-302 also recognizes Purkinje cells outside the caudal vermis and the flocculus. D. Rat-302 positive cells in the vermis. E and F. Unipolar brush cells recognized by Rat-302 have a round cell body and short dendrites ending in a spray of appendages (arrows), g, granular layer m, molecular layer p, Purkinje cell layer. Scale bars 500 fim in A and B, 50 /rm in C and D. 10 /rm in E and F. Hockfield (1987).

Purkinje cells in certain parts of rat and guinea pig cerebellum, including the lobules IX and X of the caudal vermis, display a transient reactivity for AChE, which disappears later. AChE was localized in adult Purkinje cells of the lobules IX and X (Robertson et al., 1991) these cells are arranged in multiple, sagittal bands (Gorenstein et al., 1987). Robertson et al. (1991), however, were unable to confirm the transient staining with AChE in rat Purkinje cells. 

Fig. 98. Cerebellum of the cat. The continuity in the folial chains of vermis and hemisphere is indicated by lines in the diagrams. CRI = crus I of the ansiform lobule CRII = crus II of the ansiform lobule FLO = flocculus LOB ANT/POST = anterior/posterior lobe PFLD = dorsal paraflocculus PFLV = ventral parafloc-culus PMD = paramedian lobule SI = simple lobule VII-X = lobules of the caudal vermis. Bigare (1980).

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... 

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. 

Differences between both patterns involve the distribution of the marker within the bands. Both for 5 -N and Zebrin I the intensity of the staining falls off in the more laterally located bands, but the sharp lateral borders and the differences in reactivity between the 5 -N-positive bands of the caudal vermis are not as clear with staining for Zebrin I. Moreover Zebrin I immunoreactivity extends into the Purkinje cell axons and compartments of Zebrin I-positive and -negative axons are present in the white matter that reflect the zonal distribution of the corresponding Purkinje cells. 

Fig. 140. Computer drawing of the reconstruction of the Zebrin Purkinje cells bands in the unfolded adult C57/B6 mouse cerebellum. The drawing was from immunostained 40 fim thick coronal frozen sections. The continuity of the bands has been determined as best as possible. On the left and bottom are the scales in millimeters. The two axes have different magnifications. On the right are marked the approximate boundaries of the vermal lobules. The flocculus and paraflocculus are not illustrated. One place where the data are ambiguous is within lobule V-VI, where a large number of short bands more caudally are dramatically reduced to just three at the rostral limit. It is not clear whether the P2 + or P3 + bands extend through the anterior lobe vermis (see also Fig. 139). The reconstruction data from coronal sections were not suitable to resolve the issue, so the cerebellum has also been reconstructed from horizontal sections. The upper inset panel shows the data from such a reconstruction, equivalent to the region indicated by a rectangle on the main drawing (scale in millimeters). The preferred interpretation is that the P2+ compartment does not extend far into the anterior lobe vermis, and that the first lateral Zebrin + band in lobules I-IV is continuous with P3+ (as indicated by continuous lines in the upper inset panel and as shown in the main drawing). The alternative hypothesis, that the first lateral Zebrin + band in lobules I-IV is continuous with P2+, is shown schematically in the lower inset panel. Eisenman and Hawkes (1993).

The corticovestibular and corticonuclear projections of the flocculus and the caudal vermis. Correlations with cytochemical zones and compartments... 

The zonal organization of the efferent connections of the caudal vermis in the rabbit is quite complex, with discrete zones in the lobules IX and X projecting to the fastigial, descending, superior and medial vestibular nuclei, and lateral zones connected to the interposed and different subdivisions of the lateral cerebellar nucleus (van Rossum,... 

Although the Zebrin pattern in the caudal vermis is quite distinct and some correlations with the corticonuclear projection zones are obvious (Fig. 145), no precise comparisons with the Zebrin pattern have been made. Our knowledge of the cortico-vestibular and nuclear projection of the caudal vermis, therefore, is still deficient. Progress can be expected from anatomical and electrophysiological studies using the Zebrin pattern as a reference. 

Fig. 151. Diagram of the corticovestibular projections from flocculus, nodulus and uvula in Galago. Note complementarity between the projections of the flocculus and the caudal vermis. Ivn = lateral vestibular nucleus mvn = medial vestibular nucleus spvn = spinal vestibular nucleus svn= superior vestibular nucleus. Haines (1977a).

The dorsomedial subdivision of the caudal MAO was indicated as group beta by Brodal (1940). Three parallel, longitudinal cell columns, indicated from laterally to medially as a, b and c (c is the equivalent to the group beta) were distinguished in the caudal MAO of the macaque monkey (Bowman and Sladek, 1973). Four columns (a, b, c and beta) were delineated in the caudal MAO of the rat (Gwyn et al., 1977). This apparent discrepancy was solved by Frankfurter et al. (1977) and Ikeda et al. (1989), who showed that subnucleus b in squirrel and macaque monkeys can be subdivided into medial and lateral parts and that only the medialmost region of this subnucleus is connected with the oculomotor vermis (lobule VII) and, therefore, corresponds with subnucleus c in the rat (Hess, 1982b Akaike, 1992). 

Fig. 172. Origin from the border region of the rostral and caudal medial accessory olive of the olivocerebellar projection to the electrophysiologically identified x zone in the cat, a = a zone b = b zone P = subnucleus beta cpCj = CpC, zones coll = inferior colliculus d, dj = d, and d2 zones dmcc = dorsomedial cell column MAO = medial accessory olive ml = midline pvg = lateral border of vermis x = x zone IV, V = lobules IV and V. Redrawn from Campbell and Armstrong (1985).

The investigations of Wiklund et al. (1984), using selective retrograde transport of [ H]D-aspartate were done in rats. The injection sites in the cerebellar cortex were relatively large and defied a detailed analysis of the material in terms of zones. Their experiments clearly confirmed the presence of branching olivocerebellar fibers between the anterior lobe and lobule VIII of the caudal vermis and the paramedian lobule. Moreover, their experiments clearly showed the presence of collateral projections to the cerebellar nuclei and to Deiters nucleus (Fig. 180). 

Vestibulocerebellar mossy fibers take their origin from neurons in all vestibular nuclei, with the exception of the Deiters nucleus and a sparse projection from the magnocellular medial vestibular nucleus (Figs 200 and 201). The distribution of neurons projecting to either flocculus or caudal vermis or to both is rather similar and is bilaterally symmetrical. Most neurons were found in the medial, superior and descending vestibular nuclei in this order. Neurons projecting to lobules IX and X, to the flocculus and to both parts of the cerebellum occur in a ratio of 12 4 1 (Epema et al.,... 

Fig. 199. Primary and secondary vestibulocerebellar mossy fiber projections in the rabbit, determined with antegrade axonal transport of [3H]leucine and WGA-HRP. Upper panels sagittal sections lower panels transverse sections through the caudal vermis. K196 ipsilateral distribution of fibers of the vestibular nerve. Gerrits et al., (1989) C2098 bilateral distribution of fibers from the medial vestibular nucleus (MV) K82 bilateral distributions of fibers from the superior vestibular nucleus (SV Thunnissen et al., 1989). Dense termination in the sagittal sections is indicated with heavy hatching, scattered labelled mossy fiber rosettes with light hatching and dots. Note similarity in the distribution of primary and secondary vestibulocerebellar projections.

The dorsal spinocerebellar tract takes its origin from Clarke s column and from a group of neurons in Rexed s (1954) dorsal laminae IV-VI (see Yaginuma and Matsushita, 1987 Matsushita and Hosoya, 1979 Matsushita et al., 1979 and Grant and Xu, 1988, and Xu and Grant, 1994, for complete references on rat and cat). It terminates, mainly ipsilaterally, in nine strips in the vermis, the pars intermedia and the extreme lateral part of the lobules III-V of the anterior lobe (Fig. 206C), bilaterally in lobule Vlll of the caudal vermis and in parts of the paramedian lobule. 

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