The cerebellar corticovestibular projection in the cat as studied with retrograde transport of horseradish peroxidase (original) (raw)
Related papers
Anatomy and Embryology, 1979
The cerebellar corticonuclear and nucleocortical connections of lobulus simplex, crus I and II in the cat were studied by means of anterograde and retrograde transport of HRP. Previous experimental studies give evidence that the cortex of the cerebellar hemisphere in a lateromedial direction can be subdivided into five longitudinal zones. These are recognized as zones D2, D1, C3, C2 and C1. Our observations indicate that each cortical zone has its own field of termination in the cerebellar nuclei, and that these nuclear fields are similar to those receiving afferents from the corresponding zones within the paramedian lobule (Dietrichs and Walberg, 1979). The Purkinje axons from each folium terminate from medial to lateral along a continuous band which loops through the cerebellar nuclei from the ventromedial part of nucleus interpositus posterior to the dorsolateral part of the same nucleus, from where it proceeds into the lateral part of nucleus interpositus anterior and the transition area between nucleus interpositus anterior and the dentate nucleus, to end within the latter. In addition to this arrangement there is a rostrocaudal organization within the hemispheral cortex so that the nuclear bands receiving Purkinje axons from the rostral folia (lobulus simplex) are situated slightly ventral to those receiving terminal fibres from the middle folia (crus I), which again are situated ventral to the terminal bands for the caudal folia (crus II). The nucleocortical projection shows largely the same zonal arrangement as the corticonuclear, but labelled nuclear neurons are in some cases found bilaterally within the fastigial nucleus. This nucleus does not receive Purkinje axons from lobulus simplex, crus I and crus II. Offprint requests to.
Anatomy and Embryology, 1979
The cerebellar projection from the lateral reticular nucleus (NRL) was studied in cats by means of retrograde axonal transport of horseradish peroxidase (the projection to the paramedian lobule was not included, see Brodal, 1975, for afferents to this cortical region). The entire cerebellar cortex and all cerebellar nuclei receive fibres from the NRL. The strongest connection is with the anterior lobe and lobulus VIIIB of the posterior lobe vermis. As concerns the anterior lobe the observations confirm the previous finding by Brodal (1975) that there is a clearcut topical pattern in the nuclear projection to this part of the cerebellum. The observations furthermore show that crus II is the only cerebellar region devoid of fibres from the subtrigeminal part of the NRL. The cerebellar projection from the NRL is bilateral with a heavy ipsilateral preponderance. The large majority of the labeled cells within the NRL are of the small category (< 25 ~tm in size). This and the other findings are discussed in relation to previous studies on ,the efferent and afferent connections of the nucleus.
The cerebellar nucleo-olivary projection in the cat
Anatomy and Embryology, 1981
The crossed cerebello-olivary projection in the cat was studied by means of retrograde transport of HRP. The cerebello-olivary connection is organized according to a zonal pattern similar to that of the olivocerebellar projection. However, some labelled neurons are in addition found in cerebellar nuclear areas adjacent to a nuclear zone sending its fibres to the corresponding olivary region. This observation indicates that there is a certain degree of overlapping between the different nuclear zones. The cerebello-olivary fibres from the fastigial nucleus appear to be more widely distributed than those from the other cerebellar nuclei. Nuclear neurons of all sizes project to the inferior olive, but the majority of the cells are medium sized. The findings are discussed and related to previous studies on the cerebelloolivary connection.
Electrophysiological study of the corticonuclear projection in the cat cerebellum
Brain Research, 1985
l. Experiments were designed to examine the relationship between the responses of Purkinje cells to natural peripheral stimuli and the location of these neurons within identified zones of the corticonuclear projection in lobule V of the cat cerebellar cortex. It was hypothesized that the corticonuclear zones are sharply demarcated and that the responses of Purkinje cells to a restricted natural stimulus is not localized to only one zone but rather is present and varies in character across these 3 zones. 2. Initially the spatial distribution of the antidromic field potential evoked by stimulating in the fastigial (FN), lateral vestibular (LVN), and anterior interposed nuclei (AIN) was determined in sublobules Va-Vc in unanesthetized decerebrate cats. In some animals the corticonuclear projection was further examined by evaluating the location of Purkinje cells responding antidromically to stimuli in the FN, LVN and AIN, or FN, AIN and the posterior interposed nuclei (PIN). Once a Purkinje cell was identified, its simple and complex spike responses to a step-like flexion-extension passive movement of the ipsilateral forepaw were determined. 3. The boundary based on the antidromic activation of Purkinje cells between the fastigial zone (FZ) and the anterior interposed zone (AIZ) in sublobules Va-Vc of the cerebellar cortex was highly reproducible from cat to cat, although there was a slight overlap between these zones based on the antidromic field potential. The FZ-AIZ border was located at 2,1 + 0.12 mm lateral and parallel to the midline. The FZ also contained a few cells projecting to the LVN. However, the AIZ only contained neurons projecting to the AIN. The boundary between AIZ and PIZ in lobule Va-Vc was between 3.3 and 3.8 mm from the midline and ran parallel to it. 4. The peristimulus time histograms (PSTHs) of the simple and complex spike activity to a passive forepaw displacement revealed extensive modulation of neurons located across the mediolateral extent of the AIZ and PIZ. Both the simple and complex spike discharge of Purkinje cells projecting to the FN also were modulated, but to a lesser degree than cells in AIZ or PIZ. The spatial distribution of simple and complex spike responses recorded from Purkinje cells overlapped extensively. 5. The data support previous findings that the corticonuclear projection is organized into longitudinally oriented sagittal zones. Electrophysiologically the boundaries were remarkably reproducible from animal to animal. The results also show that information processing involving the modulation of Purkinje cell activity in response to the forepaw stimulus occurs in all 3 zones examined. The tigh t spatial correlation between simple and complex spike modulation is consistent with the hypothesis that the climbing fiber input acts to increase the responsiveness of Purkinje cells and their neighboring neurons to mossy fiber inputs. (IZ) projecting to the interposed nucleus (IN); and (3) the lateral zone projecting to the dentate nucleus 11,38.39. Electrophysiological experiments showed that the characteristics of movements evoked by stimulation in the MZ differed from those evoked by stimulation in the IZ. Furthermore, lesions of the FN result in a different spectrum of neurological deficits than lesions of the IN 12,13. These earlier results supported the view that the cerebellar corticonuclear projection is anatomically and functionally organized into longitudinally oriented sagittal zones. The discreteness of the corticonuclear zones was challenged by some investigators who found more overlap between zones than originally suggested4,6,15,20.21. Cerebellar cortical lesions reportedly restricted to one of the sagittal zones
Experimental Brain Research, 1978
Details of cerebellar afferent projections from the perihypoglossal nuclei were studied in the cat by means of retrograde axonal transport of horseradish peroxidase (HRP). Labeled cells were observed bilaterally (with a preponderance ipsilaterally) in nuclei intercalatus and praepositus hypoglossi following injections in various folia of the entire vermis, paraflocculus, flocculus, fastigial nucleus, and the nucleus interpositus anterior and posterior. Relatively high densities of labeled cells were found in nucleus intercalatus following injections in the anterior part of the vermis, whereas labeled cells in nucleus praepositus hypoglossi were found more frequently following injections in the posterior part of the vermis. Labeled cells in the nucleus of Roller were found only following injections in the anterior lobe vermis, posterior vermal lobules VI and VII, in the flocculus and in the nucleus interpositus anterior. No labeled cells could be detected in the three subdivisions of the perihypoglossal nuclei following HRP injections in crus I, crus II, paramedian lobule, and lateral cerebellar nucleus. The distribution of the HRP positive cells indicated the presence of a topographically organized projection from certain regions of the perihypoglossal nuclei to different parts of the cerebellum. The afferent and efferent connections of the perihypoglossal nuclei in relation to a functional role in eye and head movements are discussed.
Anatomy and Embryology, 1980
Injections of horseradish peroxidase into the various parts of the cerebellar cortex and the cerebellar nuclei in the cat result in labelled cells within the reticular formation proper. All the reticular nuclei (with the exception of the reticular formation of the mesencephalon) send fibres to the cerebellum. The highest number of labelled neurons after cerebellar injections is found in the caudal reticular formation, especially within nucleus reticularis ventralis, nucleus reticularis lateralis and nucleus reticularis gigantocellularis. Another region for an accumulation of labelled cells is the rostral part of nucleus reticularis pontis caudalis. Except for the paraflocculus, all cerebellar cortical areas and all cerebellar nuclei receive afferents from one or more of the nuclei within the reticular formation proper, but the largest number of labelled neurons is observed in cases with injections including the intermediate-lateral part of lobulus simplex and the adjacent areas of the anterior lobe and crus I. The projection is bilateral with an ipsilateral preponderance (the cerebellar nuclei appear to receive a higher number of fibres from the contralateral side). Cells of all sizes are labelled, but labelled giant cells are found only after large cortical injections.
Neuroscience, 1979
The pontocerebellar projection has been studied in the Rhesus monkey by use of the retrograde axonal transport of horseradish peroxidase. The parts of the cerebellum investigated receive afferents from pontine celf groups arranged as rostr~udally oriented lamella or slab-like regions. As a rule labelled cells are found at all rostro-caudal levels in discrete groups, but their number at various levels, and particularly their distribution in the transverse plane, differ according to which part of the cerebellum has been injected. Although the same cell group may apparently be labelled after injections of different parts of the cerebellum, each cerebellar region has its own characteristic territory in the pontine nuclei. The anterior lobe receives fibres from lamely-like regions mainly in the caudal half of the pons, with cells projecting to the vermis and intermediate parts of the anterior lobe somewhat differently situated. Crus I is connected mainly with a region rostromedially in the pons, while crus II receives fibres from all levels of the pons, the cells being located medially and ventrally at caudal levels and more laterally at rostra1 levels. The param~ian lobule is supplied from pontine cells restricted to the rostra1 two-thirds of the pons and located more laterally than those projecting to crus II. Lobules VII and VIIIA (the main part of the vermal visual area) receive fibres mainly from two long column-like regions located dorsomedially and dorsolaterally, while lobulus VIIIB is supplied mainly from other areas in the pons.
Brain Research, 1977
Following injections of horseradish peroxidase (HRP) in cerebellar vermal lobules VI, VIIA and B, VIIIA and B in the cat, the distribution of labeled cells in the pontine nuclei was mapped in drawings of serial transverse and horizontal sections. The labeled pontine cells are distributed in 4 largely longitudinal columns, situated in the dorsolateral, peduncular, lateral and paramedian pontine nucleus (referred to as columns A, B, C and D, respectively). The majority of afferents to the vermal, visual areas come from columns A and B. To some extent cells projecting to the various sublobules have their preferential location within each column . The majority of the fibers end in lobule VII.