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F Walberg

Publications and source records attributed to F Walberg.

At least 55 records · Page 3Linked to original sources
PubMed1981

The cerebellar nucleo-olivary projection in the cat.

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 cerebello-olivary connection.

Animals↗
PubMed1980

A re-examination of the cerebellar projections from the gracile, main and external cuneate nuclei in the cat.

Cerebellar projections from the dorsal column and external cuneate nuclei in the cat have been studied by means of retrograde axonal transport of horseradish peroxidase. Localized injections covering the entire cerebellar cortex and nuclei show that the gracile nucleus has a weak projection only to the cortex of the anterior lobe, but that there is a conspicuous projection from the main cuneate nucleus to the cerebellum. Most of these fibres reach lobule V and the adjacent parts of lobules IV and VI, and there is also a heavy projection to the paramedian lobule. Some fibres reach lobule IX and possibly also lobules II, III and VIIIB, and nuclear afferents also reach the fastigial and interposite nuclei. Three cerebellar cortical regions are the main targets for the fibres from the external cuneate nucleus, viz. lobule V with the adjacent regions of lobules IV and VI, lobules I and II and lobule IX (the anterior part). Other important afferent regions are the paramedian lobule and the cerebellar nuclei, especially the anterior interposite, and some fibres reach the flocculus. The projections are predominantly ipsilateral. The investigation is the first detailed study of the cerebellar projections from the three nuclei and the findings are discussed in relation to previous experimental observations.

Animals↗
PubMed1980

The vestibulothalamic projections in the cat studied by retrograde axonal transport of horseradish peroxidase.

Horseradish peroxidase (HRP) was injected or iontophoretically ejected in various thalamic nuclei in 63 adult cats. In 11 other animals HRP was deposited outside the thalamic territory. The number and distribution of labelled cells within the vestibular nuclear complex (VC) were mapped in each case. To a varying degree all subgroups of VC appear to contribute to the vestibulothalamic projections. Such fibres are distributed to several thalamic areas. From the present investigation it appears that generally speaking, there exist three distinct vestibulothalamic pathways with regard to origin as well as to site of termination of the fibres. One projection appears to originate mainly in caudal parts of the medial (M) and descending (D) vestibular nuclei and in cell group z. This pathway terminates chiefly in the contralateral medial part of the posterior nucleus of the thalamus (POm) including the magnocellular part of the medial geniculate body (Mgmc), the ventrobasal complex (VB) and the area of the ventral lateral nucleus (VL) bordering on VB. A second projection originates mainly in the superior vestibular nucleus (S) and in cell group y and terminates mainly in the contralateral nucleus centralis lateralis (CL) and the adjoining nucleus paracentralis (Pc). A third, more modest, pathway originates chiefly in the middle M and D, with a minor contribution from S and cell group y, and terminates in the contralateral ventral nucleus of the lateral geniculate body (GLV). There is some degree of overlap between the origin of these three vestibulothalamic pathways.

Animals↗
PubMed1980

A note on the anterograde transport of horseradish peroxidase within the olivocerebellar fibres.

In cats with unilateral injections of horseradish peroxidase in the inferior olive which were processed according to the Mesulam (1978) technique crossed olivocerebellar fibres can be followed on both sides of the brain stem into the cerebellum to the level of the granular layer. The observations indicate that perikaryal uptake of horseradish peroxidase is not a prerequisite for the visualization of the fine preterminal fibres.

Animals↗
PubMed1980

Cerebellar afferents from the trigeminal sensory nuclei in the cat.

The cerebellar afferent projection from the trigeminal sensory nuclei (TSN) was studied by means of retrograde axonal transport of horseradish peroxidase (HRP). The projection is almost exclusively ipsilateral. Three cortical regions, viz., the intermediate-lateral part of lobulus simplex with the adjacent area of lobule V, the rostralmost folia of the paramedian lobule with the surrounding parts of crus I and II, and lobule IX, especially its rostral two folia, are the main targets for the cerebellar afferent fibres. A few fibres reach also the other cerebellar regions, as shown in Fig. 3. Most of the cerebellar afferent fibres originate in the nucleus interpolaris with nucleus oralis as the second most important region. The projection from the principal nucleus is moderate and reaches primarily the area of the crura bordering on the paramedian lobule and lobule IX. The projections from the nucleus caudalis and nucleus mesencephalicus are scanty. The fibres from the latter reach only the vermal region. The findings are discussed in relation to previous anatomical and physiological observations.

Afferent Pathways↗
PubMed1980

The reticulocerebellar projection in the cat as studied with retrograde transport of horseradish peroxidase.

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.

Animals↗
PubMed1979

The longitudinal zonal pattern in the paramedian lobule of the cat's cerebellum: an analysis based on a correlation of recent HRP data with results of studies with other methods.

In a preceding study of the distribution of retrogradely labeled cells in the inferior olive of the cat after microinjections of horseradish peroxidase (HRP) in the contralateral paramedian lobule (Brodal and Walberg, '77b), three longitudinal zones were distinguished. The zones were assumed to correspond to Voogd's zones C1, C2 and D, receiving their afferents from parts of the dorsal accessory olive, of the medial accessory olive and of the dorsal lamella of the principal olive, respectively. Labeled cells were not found in the ventral lamella of the principal olive, however, although there is no doubt that also this projects to the paramedian lobule. In the present study, iontophoretic ejections, covering the extreme lateral part of the paramedian lobule, gave rise to labeling of cells in the ventral lamella. It is concluded that the zone D in the paramedian lobule can be subdivided into two, a lateral, D2, and a medial, D1, receiving fibers from the ventral and dorsal lamella, respectively. Neither zone extends throughout the entire length of the paramedian lobule. Both are lacking most rostrally and most caudally. This and other findings prompted a renewed analysis of the entire pattern of zonal representation in the paramedian lobule, based on correlations of our observations with the HRP method with data obtained with other methods. The results of this analysis are briefly described and summarized in a diagram (fig. 3B). It is particularly remarkable that zone B is present in some folia medially. A somatotopical arrangement appears to be present within all zones. A full account and documentation will be presented separately (Brodal and Kawamura, '80).

Animals↗
PubMed1979

The cerebellar projection from the lateral reticular nucleus as studied with retrograde transport of horseradish peroxidase.

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 (less than 25 micrometer in size). This and the other findings are discussed in relation to previous studies on the efferent and afferent connections of the nucleus.

Animals↗
PubMed1979

The olivocerebellar projections to the flocculus and paraflocculus in the cat, compared to those in the rabbit. A study using horseradish peroxidase as a tracer.

The projections from the inferior olive to the flocculus and paraflocculus in the cat have been mapped by means of the method of retrograde axonal transport of horseradish peroxidase. The findings show that the afferents to the flocculus are derived from the dorsal cap, ventrolateral outgrowth, the principal olive (the caudal parts of the ventral and dorsal lamella) and from the rostral part of the medial accessory olive. The fibres to the paraflocculus come from the caudal part of the principal and from the rostral part of the medial accessory olive. Details in the projections are seen from Figs. 1 and 2. Concerning some points the findings are at variance with those made in the rabbit by Hoddevik and Brodal, and suggest that there are species differences hitherto not known.

Animals↗
PubMed1979

The pontine projection onto longitudinal zones of the paramedian lobule in the cat.

The distribution of labeled cells in the pontine nuclei was studied following microinjections of horseradish peroxidase into three longitudinal zones in the paramedian lobule in the cat. Labeled cells were only found when the staining of the cerebellar cortex included the granular layer. The labeled cells were present contralateral to the injection site in the cases with the smallest injections, in the others there was a bilateral distribution with a contralateral preponderance. The labeled cells lie concentrated in three groups medially, ventrally, and laterally to the peduncle. No indication of a different projection from these three groups to the three longitudinal paramedian zones was found, although in the same material a zonal projection exists for the climbing fibers from various parts of the inferior olive to the same cerebellar lobule (Brodal and Walberg, 1977).

Afferent Pathways↗
PubMed1979

Cerebellar afferents from the nucleus of the solitary tract.

The cerebellar afferents from the nucleus of the solitary tract were studied in cat by means of retrograde axonal transport of horseradish peroxidase. Labelled cells occurred bilaterally in the nucleus of the solitary tract following injections in various folia of the cerebellar vermis and in the flocculus (the positive cases are shown in Fig. 1A). Injections in the anterior lobe vermis labelled cells in the caudal part of the nucleus, injections in the posterior vermis labelled cells in the rostral part (Fig. 2). The findings are discussed in relation to other efferent and afferent connections of the nucleus of the solitary tract.

Animals↗
PubMed1979

The cerebellar projection from the paratrigeminal nucleus in the cat.

The cerebellar afferent projection from the paratrigeminal nucleus (PTN) was studied in the cat by means of retrograde axonal transport of horseradish perioxidase (HRP). Most of the afferent fibres reach the cerebellar lobules I, II, V (hemispheral part), VIIIB and IX, the paramedian lobule and the fastigial nucleus. The total distribution of the cerebellar afferents is shown in Fig. 2. The findings extend Chan-Palay's [2,3] recent studies on the cytology, synaptic organization and neurotransmitter content of the paratrigeminal nucleus in monkey and rat.

Afferent Pathways↗