Neurones in the adult rat anterior medullary velum

Ibrahim, Merdol; Menoud, Pierre-Alain; Celio, Marco R.

doi:10.1002/(sici)1096-9861(20000327)419:1<122::aid-cne7>3.0.co;2-x

Cited by 6 publications

(3 citation statements)

References 55 publications

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“…This wide territory contains various fiber systems, which may provide adequate inputs for ectopic CN and cerebellar neurons. Indeed, ectopic Purkinje cells, granule cells and UBCs that remain trapped in the white matter because of incomplete or faulty migration can nevertheless survive well into adulthood and form synaptic junctions (De Camilli et al, 1984;Ibrahim et al, 2000;Sekerková et al, 2004a;Ilijic et al, 2005). We found it notheworthy that in our α6/ mGluR1α labeled section series Purkinje cells were rarely encountered in the subpeduncular corner and its extended lips (unpublished observations), which suggested that its granule cells and UBCs belong to the CN.…”

Section: Sources and Distribution Of Gcs Afferentsmentioning

confidence: 55%

Distribution and phenotypes of unipolar brush cells in relation to the granule cell system of the rat cochlear nucleus

Diño

Mugnaini

2008

Neuroscience

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In most mammals the cochlear nuclear complex (CN) contains a distributed system of granule cells (GCS), whose parallel fiber axons innervate the dorsal cochlear nucleus (DCN). Like their counterpart in cerebellum, CN granules are innervated by mossy fibers of various origins. The GCS is complemented by unipolar brush (UBCs) and Golgi cells, and by stellate and cartwheel cells of the DCN. This cerebellum-like microcircuit modulates the activity of the DCN's main projection neurons, the pyramidal, giant and tuberculoventral neurons, and is thought to improve auditory performance by integrating acoustic and proprioceptive information. In this paper, we focus on the rat UBCs, a chemically heterogeneous neuronal population, using antibodies to calretinin, metabotropic glutamate receptor 1alpha (mGluR1alpha), epidermal growth factor substrate 8 (Eps8) and the transcription factor T-box gene Tbr2 (Tbr2). Eps8 and Tbr2 labeled most of the CN's UBCs, if not the entire population, while calretinin and mGluR1alpha distinguished two largely separate subsets with overlapping distributions. By double labeling with antibodies to Tbr2 and the alpha6 GABA receptor A (GABAA) subunit, we found that UBCs populate all regions of the GCS and occur at remarkably high densities in the DCN and subpeduncular corner, but rarely in the lamina. Although GCS subregions likely share the same microcircuitry, their dissimilar UBC densities suggest they may be functionally distinct. UBCs and granules are also present in regions previously not included in the GCS, namely the rostrodorsal magnocellular portions of ventral cochlear nucleus, vestibular nerve root, trapezoid body, spinal tract and sensory and principal nuclei of the trigeminal nerve, and cerebellar peduncles. The UBC's dendritic brush receives AMPA- and NMDA-mediated input from an individual mossy fiber, favoring singularity of input, and its axon most likely forms several mossy fiber-like endings that target numerous granule cells and other UBCs, as in the cerebellum. The UBCs therefore, may amplify afferent signals temporally and spatially, synchronizing pools of target neurons.

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Section: Sources and Distribution Of Gcs Afferentsmentioning

confidence: 55%

Distribution and phenotypes of unipolar brush cells in relation to the granule cell system of the rat cochlear nucleus

Diño

Mugnaini

2008

Neuroscience

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“…In a conversation with one of us (E. M.), the late Sanford L. Palay once suggested that, in Golgi sections, UBCs might have been mistaken for Purkinje cells that had remained in a dwarfed state, having failed to reach the proper position in the cortex. Due to several specific cell markers, such as guanosine 3:5-phosphate dependent protein kinase spot35/calbindin, we now know that migrating, immature or ectopic Purkinje cells (De Camilli et al, 1984; Takahashi-Iwanaga et al, 1986; Vastagh et al, 2005a,b) are much larger in size and do not resemble in profile migrating, immature or ectopic UBCs (Morin et al, 1981; Munoz, 1990; Diño et al, 1999; Ibrahim et al, 2000; Víg et al, 2005). Another intriguing possibility may be that the UBCs, if noticed, were ignored because they did not fit with current epistemic systems.…”

Section: The Early Yearsmentioning

confidence: 99%

“…Scattered UBCs also occur ectopically in the white matter of the cerebellar peduncle and the medullary vela (Ibrahim et al, 2000). These findings likely reflect the cells’ migratory pathways, as considered above.…”

Section: Comparative Studies On the Lobular Distribution Of Mammalianmentioning

confidence: 99%

The unipolar brush cell: A remarkable neuron finally receiving deserved attention

Mugnaini

Sekerková

Martina

2011

Brain Research Reviews

167

152

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Unipolar brush cells (UBC) are small, glutamatergic neurons residing in the granular layer of the cerebellar cortex and the granule cell domain of the cochlear nuclear complex. Recent studies indicate that this neuronal class consists of three or more subsets characterized by distinct chemical phenotypes, as well as by intrinsic properties that may shape their synaptic responses and firing patterns. Yet, all UBCs have a unique morphology, as both the dendritic brush and the large endings of the axonal branches participate in the formation of glomeruli. Although UBCs and granule cells may share the same excitatory and inhibitory inputs, the two cell types are distinctively differentiated. Typically, whereas the granule cell has 4-5 dendrites that are innervated by different mossy fibers, and an axon that divides only once to form parallel fibers after ascending to the molecular layer, the UBC has but one short dendrite whose brush engages in synaptic contact with a single mossy fiber terminal, and an axon that branches locally in the granular layer; branches of UBC axons form a non-canonical, cortex-intrinsic category of mossy fibers synapsing with granule cells and other UBCs. This is thought to generate a feed-forward amplification of single mossy fiber afferent signals that would reach the overlying Purkinje cells via ascending granule cell axons and their parallel fibers.In sharp contrast to other classes of cerebellar neurons, UBCs are not distributed homogeneously across cerebellar lobules, and subsets of UBCs also show different, albeit overlapping, distributions. UBCs are conspicuously rare in the expansive lateral cerebellar areas targeted by the cortico-ponto-cerebellar pathway, while they are a constant component of the vermis and the flocculonodular lobe. The presence of UBCs in cerebellar regions involved in the sensorimotor processes that regulate body, head and eye position, as well as in regions of the cochlear nucleus that process sensorimotor information suggests a key role in these critical functions; it also invites further efforts to clarify the cellular biology of the UBCs and their specific functions in the neuronal microcircuits in which they are embedded. High density of UBCs in specific regions of the cerebellar cortex is a feature largely conserved across mammals and suggests an involvement of these neurons in fundamental aspects of the input/output organization as well as in clinical manifestation of focal cerebellar disease.

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Morphogenesis of the cerebellum and cerebellum-related structures in the shark Scyliorhinus canicula: insights on the ground pattern of the cerebellar ontogeny

et al. 2015

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Because the cerebellum emerged at the agnathan-gnathostome transition and cartilaginous fishes are at the base of the gnathostome lineage, this group is crucial to determine the basic developmental pattern of the cerebellum and to gain insights into its origin. We have systematically analyzed key events in the development of cerebellum and cerebellum-related structures of the shark Scyliorhinus canicula. Three developmental periods are distinguished based on anatomical observations combined with molecular analysis. We present neurochemical and genoarchitectonic evidence on the onset of cerebellar development, the rostral and caudal cerebellar boundaries, the compartmentalization of the cerebellum, and correspondence of cerebellar domains to rhombomeric segmentation of the rostral hindbrain. Our observations, mainly based on the expression pattern of ScHoxA2, support the origin of both the upper and lower auricular leaves from r1 and exclude any cerebellar origin from r2. Correlation between subrhombomeres r1a/r1b and cerebellar domains is proposed based on the ScEn2 expression. The ScEn2 and ScOtx2 expression patterns revealed an antero-posterior cerebellar compartmentalization similar to that of mammals, and supported certain fissures (commonly used to define cerebellar domains) as reliable anatomical landmarks. At difference from mammals, the expression of ScEn2 along the cerebellar median-lateral axis does not reveal a multiple-banded pattern. The present study provides an atlas of cerebellar development in one of the most basal extant gnathostome lineages and emphasizes the importance of combining classic descriptive with modern molecular studies to gain knowledge on the ancestral condition of cerebellar developmental processes and the origins and evolution of the cerebellum.

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Neurones in the adult rat anterior medullary velum

Cited by 6 publications

References 55 publications

Distribution and phenotypes of unipolar brush cells in relation to the granule cell system of the rat cochlear nucleus

Distribution and phenotypes of unipolar brush cells in relation to the granule cell system of the rat cochlear nucleus

The unipolar brush cell: A remarkable neuron finally receiving deserved attention

Morphogenesis of the cerebellum and cerebellum-related structures in the shark Scyliorhinus canicula: insights on the ground pattern of the cerebellar ontogeny

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