Anterior lobe, cerebellum

Fig. 120. Compartments in the white matter of the cerebellum of the cat. Drawings and reconstructions from Haggqvist and AChE-stained sections. Compartments are indicated with different symbols. A-D. Graphical reconstructions of the rostral aspect of the anterior lobe (A) and the posterior lobe (B), the dorsal aspect (C) and the caudal aspect (D) of the cerebellum. Compare Fig. 98. E-G. Transverse sections. A = A compartment ANS = ansiform lobule ANT = anterior lobe B = B compartment Cl-3 = Cl-3 compartments cr = restiform body D(l,2) = D(l,2) compartments F = fastigial lateral cerebellar nucleus PFL = paraflocculus PMD = paramedian lobule SI = simple lobule vest = vestibular nuclei X = X compartment III-IX = lobules IIl-IX.

Fig. 121. Zonal distribution of AChE in the cerebellum of the cat. A. Whole mount preparation of the anterior lobe. B. Transverse section through the anterior lobe. HEM = hemisphere m = midline AChE-positive band L = parasagittal AChE-positive band arrows = lateral border of L. Marani (1986).

Fig. 122. Photographs of white matter of the anterior lobe of the cerebellum of the cat. A. Borders of compartments and midline (m) are delineated by AChE-reactive raphes. The lateral border of the X compartment is in line with the lateral border of the parasagittal AChE-positive strip in the molecular layer the molecular layer over the B compartment is AChE-negative. B. Haggqvist-stain. Compartments A-D are delineated by dark stripes containing small calibre fibers. Same level as Fig. 120E.

Fig. 130. Schematic summary of cysteine sulfinic acid decarboxylase (CSADCase)-positive sagittal microzones or bands in mouse cerebellum. The bands are clearest in the anterior lobe and the vermis, less sharply defined in the hemispheres (dense stipple), and most difficult to discern in the paraflocculus and flocculus (light stipple), because of intense CSADCase reactivity in most Purkinje cells. The dentate (D), interpositus (I), fastigial (F), and lateral vestibular nuclei (LVN) contain numerous CSADCase-positive cells. Chan-Palay et al. (1982b).

Fig. 131. Reconstructions of the zonal distribution of 5 -nucleotidase (5 -N) in the molecular layer of the cerebellum of the mouse. Numbers without prefix indicate the nomenclature for the 5 -N-positive bands of Marani (1982) P-numbers on the left side refer to the nomenclature for corresponding Zebrin I-positive bands of Hawkes and Leclerc (1987). ANT = anterior lobe FLO = flocculus PFL = paraflocculus II-X = lobules...

Fig. 132. Transverse sections through lobules I-V of the anterior lobe of mouse cerebellum, reacted for 5 -nucleotidase. The 5 -nucleotidase-positive bands are numbered according to Marani (1986).

Zebrin I compartmentalization in Saimiri sciurus was studied by Leclerc et al. (1990). Both in the vermis and the hemispheres clusters of Zebrin I-immunoreactive Purkinje cells were separated by weakly stained Purkinje cell somata or unstained cells. Zebrin-negative bands, therefore, are less distinct than in rodents. P1+, P2+ and P3+ bands are continuous from lobule to lobule and become narrower in the anterior lobe. P4+-P7+ bands were tentatively identified in the hemisphere, but not analysed in detail. A complementary histochemical zonation was detected for cytochrome oxidase, that was present in patches in the granular layer corresponding to the P- bands both in squirrel monkey and rat cerebellum. It is obvious from a comparison of the illustrations from the paper of Dore et al. (1990), showing the distribution of Zebrin I immunoreactivity in Purkinje cells and their axons and the zonation of AChE in monkey cerebellum, that the P2+ immunoreactivity in the anterior vermis corresponds to the X zone, and P2-... 

Fig. 139. Drawings of three surface views of the mouse cerebellum, anterior, dorsal and posterior, showing the locations of the Zebrin+ bands of Purkinje cells. The Purkinje cell bands PI +-P7 + are labelled in the dorsal view (for clarity, only the numerals have been used). Note that in the vermis of the posterior lobe the immunoreactive Purkinje cells form five to seven bands (posterior and dorsal views), whereas in lobules VII and VI all vermal Purkinje cells are immunoreactive (posterior and dorsal view). This pattern gradually changes in the anterior lobe to result in three to five very narrow immunoreactive bands (anterior view). In the hemispheres there are three major immunoreactive bands of Purkinje cells on either side (P5b+, P6+, P7+) plus two sub-bands in the para vermal area of the paramedian and ansiform lobules (P4b-t, P5a+). Note too that the Purkinje cells are all Zebrin+ in the nodulus (lobule X, illustrated as indicated by arrows reflected out from the ventral surface of the cerebellum), the paraflocculus, and the flocculus. From Eisenman and Hawkes (1993).

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).

Fig. 174. Minimum threshold sites for evoking short latency climbing fiber responses from the pericruciate cortex of the cat in the b, c, and d, zones of the anterior lobe of cat cerebellum. ASG = anterior sigmoid gyrus PSG = posterior sigmoid gyrus. Redrawn from Andersson and Nyquist (1983).

It can be concluded that the anatomical and electrophysiological subdivisions of the pars intermedia of the anterior lobe of the cerebellum of the cat are not completely concordant (Fig. 173). Short-latency DF-SOCP innervated zones with cutaneous no-... 

The lateral zone or hemisphere proper of the anterior lobe receives a projection from the principle olive. The distinction of this projection by Brodal (1940) was based on its absence in the cat, and its presence in the anterior lobe of the cerebellum of the rabbit, that extends further laterally. Projections of the PO to the extreme lateral part of the anterior lobe of the cat have been documented by Armstrong et al. (1974), Brodal and Walberg (1977a), Groenewegen et al. (1979) and Kawamura and Hashikawa (1979). Brodal and Kawamura (1980) discussed this projection and tentatively concluded that both the ventral and dorsal lamella of the PO projected to the anterior lobe, the dorsal lamella to the medial D, zone and the ventral lamella to the lateral D2 zone. It cannot be decided whether the d, and dj zones identified in the electrophysiological studies of Ekerot and Larson (1979a, 1982) correspond to either D, or the Dj zone. 

Fig. 184. The tecto-recipient zones in the vermis (lobule VII) and the hemisphere (paramedian lobule. Crus II and simple lobule) of rat cerebellum. Note their absence from anterior lobe. Crus I and copula pyramidis. Compare Fig. 142. ANT = anterior lobe COP = copula pyramidis Crl(II) = crus 1(11) of ansiform lobule PMD = paramedian lobule SI = simple lobule. IV-IX = lobules IV-IX. Redrawn from Akaike (1992).

Fig. 208. Diagram of the fractured somatotopy of the mossy fiber projections in the cerebellum of the rat. Patches with similar receptive fields are indicated with abbreviations for the stimulation sites on the head and the extremities. Redrawn from Welker (1987). Cr = crown El = eyelids Fbp = furry buccal pad FL = forelimb and hand G = gingiva HL = hindlimb I, II = crus I and II Li = lower incisor LI = lower lip Lob.ant. = anterior lobe lob.sim = lobulus simplex N = nose Nk = neck P = pinna PFL = paraflocculus PML = paramedian lobule PY = pyramis Rh = rhinarium Ui = upper incisor U1 = upper lip UV = uvula.

The distribution of CRF-immunoreactive mossy fibers in the cerebellum of the cat is very similar to the opossum, with concentrations of mossy fibers underlying the stained bands of immunoreactive climbing fibers in vermis and pars intermedia, and heavy labelling in the flocculonodular lobe (Cummings, 1989) (Fig. 194). The localization of CGRP-immunoreactive mossy fibers over the cerebellum of the cat differs substantially from that of the other peptides. They are present in the paraflocculus, the paramedian and ansiform lobules and in the pars intermedia of the simple lobule and the anterior lobe. In the anterior vermis they are located in the apices of the lobules. 

Bishop GA (1982) Pattern of distribution of the local axonal collaterals of Purkinje cells in the intermediate cortex of the anterior lobe and paramedian lobule of the cat cerebellum. J. Comp. Neurol, 210, 1-9. Bishop GA (1984) The origin of the reticulo-olivary projection in the rat a retrograde horseradish peroxidase... 

Provini L, Redman S, Strata P (1967) Somatotopic organization of mossy and climbing fibres to the anterior lobe of cerebellum activated by the sensorimotor cortex. Brain Res., 6, 378-381. 

Aggressiveness results from the failure of inhibitory neurochemical processes or exaggeration of stimulatory processes in brain regions, such as the orbito-ffontal cortex, the septal area, hippocampus, amygdala, caudate nucleus, thalamus, ventro-medial and posterior hypothalamus, midbrain tegmentum, pons, and the fastigial nuclei and anterior lobe of the cerebellum. 

Cerebellum anterior lobe culme Cerebellum posterior lobe declive Cerebellum posterior lobe pyramis Cerebellum posterior lobe uvula Cerebellum posterior lobetonsil Cerebellar vermis (VC)... 

Also, an increase in sway with the eyes closed in the right-left direction was significantly related to the mean blood concentration in the past. According to Yokoyama et al. (1997), the change in the vestibulo-cerebellum seemed to reflect current lead absorption, whereas the change in the anterior cerebellar lobe reflected past lead absorption. 

The cerebellum lies posterior to the brainstem and is separated from it by the fourth ventricle. Anatomically it is divided into two hemispheres, each consisting of three lobes (anterior, posterior, and flocculonodular). The function of the cerebellum is to help plan and coordinate motor activity and to assume responsibility for comparing the actual movement with the intended motor pattern. The cerebellum interprets various sensory input and helps modulate motor output so that the actual movement closely resembles the intended motor program. The cerebellum is also concerned with the vestibular mechanisms responsible for maintaining balance and posture. Therapeutic medications are not usually targeted directly for the cerebellum, but incoordination and other movement disorders may result if a drug exerts a toxic side effect on the cerebellum. 

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