Projections from the lateral vestibular nucleus to the upper cervical spinal cord of the cat: A correlative light and electron microscopic study of axon terminals stained with PHA‐L

Rose, P. K.; Ely, Sarah; Norkum, V.; Neuber-Hess, M.

doi:10.1002/(sici)1096-9861(19990809)410:4<571::aid-cne5>3.0.co;2-#

Cited by 12 publications

(7 citation statements)

References 70 publications

(115 reference statements)

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“…7B–D). These appositions meet criteria that have been established to define synaptic contacts at the light microscopic level (Fyffe,1991; Rose et al,1999): 1) the axon formed a round or elliptical swelling whose diameter was at least twice that of the adjacent shaft; 2) there was no discernible gap between the axon and dendrite; and 3) both the swelling and the dendrite are in the same focal plane at the site of the potential contact. Four de novo axons that emerged from distal dendrites of three CINs were examined for synapse‐like contacts with MAP2a/b‐immunoreactive dendrites.…”

Section: Resultsmentioning

confidence: 84%

Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy

Fenrich

Skelton

MacDermid

et al. 2007

J of Comparative Neurology

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Following proximal axotomy, several types of neurons sprout de novo axons from distal dendrites. These processes may represent a means of forming new circuits following spinal cord injury. However, it is not know whether mammalian spinal interneurons, axotomized as a result of a spinal cord injury, develop de novo axons. Our goal was to determine whether spinal commissural interneurons (CINs), axotomized by 3-4-mm midsagittal transection at C3, form de novo axons from distal dendrites. All experiments were performed on adult cats. CINs in C3 were stained with extracellular injections of Neurobiotin at 4-5 weeks post injury. The somata of axotomized CINs were identified by the presence of immunoreactivity for the axonal growth-associated protein-43 (GAP-43). Nearly half of the CINs had de novo axons that emerged from distal dendrites. These axons lacked immunoreactivity for the dendritic protein, microtubule-associated protein2a/b (MAP2a/b); some had GAP-43-immunoreactive terminals; and nearly all had morphological features typical of axons. Dendrites of other CINs did not give rise to de novo axons. These CINs did, however, each have a long axon-like process (L-ALP) that projected directly from the soma or a very proximal dendrite. L-ALPs were devoid of MAP2a/b immunoreactivity. Some of these L-ALPs projected through the lesion and formed bouton-like swellings. These results suggest that proximally axotomized spinal interneurons have the potential to form new connections via de novo axons that emerge from distal dendrites. Others may be capable of regeneration of their original axon.

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Section: Resultsmentioning

confidence: 84%

Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy

Fenrich

Skelton

MacDermid

et al. 2007

J of Comparative Neurology

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“…It is unlikely that this result is due to a systemic inability to detect swellings. It is known that swellings on collaterals that are orthogonal to the plane of the section cannot be detected, because it is not possible to measure accurately the diameter of the swelling and adjacent shaft of the collateral (Rose et al, 1999). However, these swellings represent, at most, 10% of all swellings.…”

Section: Discussionmentioning

confidence: 99%

“…To be considered a contact, the appositions between vestibulospinal axons and splenius dendrites had to satisfy three criteria: 1) the vestibulospinal collateral formed a round or elliptical swelling whose diameter was twice that of the adjacent collateral shaft, 2) there was no discernible gap between the swelling and the dendrite, and 3) both the swelling and the dendrite at the site of the potential contact were in the same focal plane. These criteria have been applied in several studies of this kind (Fyffe, 1991; Rose et al, 1995, 1999; Alvarez et al, 1998; Carr et al, 1999), and appositions meeting these criteria have been shown to correspond to synaptic contacts at the electron microscopic level (Fyffe, 1991; Rose et al, 1999). Because of the convoluted contour of the soma, no attempt was made to determine the incidence of contacts on the “bottom” of the soma (as viewed through the microscope).…”

Section: Methodsmentioning

confidence: 99%

Distribution of contacts from vestibulospinal axons on the dendrites of splenius motoneurons

Grande

Armstrong

Neuber-Hess

et al. 2005

J of Comparative Neurology

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Current descriptions of the organization of synapses on the dendritic trees of spinal motoneurons indicate that the inputs are arranged in several patterns: some are widely distributed; some are distributed to proximal dendrites; others are distributed based on the trajectory of the dendrites. However, the principles governing the organization of synapses on spinal motoneurons remain poorly defined. Our goal was to extend the descriptions of the distribution of synapses, identified by their source, on the dendritic trees of spinal motoneurons. We combined anterograde and intracellular staining techniques in cats to determine the distribution of contacts between excitatory axons from the rostral aspect of the descending vestibular nucleus and the dendrites of motoneurons supplying a dorsal neck muscle, splenius. In five of five motoneurons, the contacts were preferentially distributed on dendrites medial to the soma. This qualitative observation was confirmed by using Monte Carlo methods. The results from this analysis showed that the distribution of contacts can be explained not by the overall distribution of the dendritic membrane area but rather by a systematic innervation of the medial regions of the dendritic trees (P < 0.02). Despite this selectivity, there was no additional bias in the distribution of contacts to proximal vs. distal dendrites. By concentrating excitatory synapses in a restricted region of the dendritic tree, the actions of vestibulospinal connections on neck motoneurons may be increased as a result of a greater probability of activating persistent inward currents on the dendrites.

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“…superior, lateral, medial and inferior) mainly involved in the control of posture and balance through its connections to the spinal cord (Highstein and McCrea 1988;Rose et al 1999). We focused on the ventral LVN, as the majority of dorsal LVN is known to be devoid of vestibular nerve endings (see for review Highstein and Holstein 2006) and thus UL may not have strong effects on the dorsal part of LVN.…”

Section: Structural Plasticity In the Lateral Vestibular Nuclei After Ulmentioning

confidence: 99%

Modifications of perineuronal nets and remodelling of excitatory and inhibitory afferents during vestibular compensation in the adult mouse

et al. 2015

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Perineuronal nets (PNNs) are aggregates of extracellular matrix molecules surrounding several types of neurons in the adult CNS, which contribute to stabilising neuronal connections. Interestingly, a reduction of PNN number and staining intensity has been observed in conditions associated with plasticity in the adult brain. However, it is not known whether spontaneous PNN changes are functional to plasticity and repair after injury. To address this issue, we investigated PNN expression in the vestibular nuclei of the adult mouse during vestibular compensation, namely the resolution of motor deficits resulting from a unilateral peripheral vestibular lesion. After unilateral labyrinthectomy, we found that PNN number and staining intensity were strongly attenuated in the lateral vestibular nucleus on both sides, in parallel with remodelling of excitatory and inhibitory afferents. Moreover, PNNs were completely restored when vestibular deficits of the mice were abated. Interestingly, in mice with genetically reduced PNNs, vestibular compensation was accelerated. Overall, these results strongly suggest that temporal tuning of PNN expression may be crucial for vestibular compensation.

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Projections from the lateral vestibular nucleus to the upper cervical spinal cord of the cat: A correlative light and electron microscopic study of axon terminals stained with PHA‐L

Cited by 12 publications

References 70 publications

Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy

Axonal regeneration and development of de novo axons from distal dendrites of adult feline commissural interneurons after a proximal axotomy

Distribution of contacts from vestibulospinal axons on the dendrites of splenius motoneurons

Modifications of perineuronal nets and remodelling of excitatory and inhibitory afferents during vestibular compensation in the adult mouse

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