Trajectory of spinocerebellar fibers passing through the inferior and superior cerebellar peduncles in the rat spinal cord: A study using horseradish peroxidase with pedunculotomy

Yamada, Jinzo; Shirao, Kuniaki; Kitamura, Taiko; Sato, Hitoshi

doi:10.1002/cne.903040111

Cited by 49 publications

(38 citation statements)

References 42 publications

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“…The drive required for the activation of the hindlimb CPGs can be provided either by tract neurons with spinal collaterals or by propriospinal neurons with direct or indirect axonal projections to the CPGs. Ascending pathways that may play this role are the spinothalamic, spinoreticular and ventral spinocerebellar tracts (Trevino et al, 1972;Fields et al, 1975;Arsénio Nunes and Sotelo, 1985;Grant, 1990, 2005;Yamada et al, 1991). Some of these pathways have been reported to send spinal collaterals to different levels of the spinal cord and thereby may potentially contribute to activation of the CPGs by SCA stimulation (see Baldissera et al, 1981).…”

Section: Discussionmentioning

confidence: 99%

Long and Short Multifunicular Projections of Sacral Neurons Are Activated by Sensory Input to Produce Locomotor Activity in the Absence of Supraspinal Control

Etlin¹,

Blivis²,

Ben-Zwi³

et al. 2010

J. Neurosci.

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Afferent input from load and joint receptors has been shown to reactivate the central pattern generators for locomotion (CPGs) in spinal cord injury patients and thereby improve their motor function and mobility. Elucidation of the pathways interposed between the afferents and CPGs is critical for the determination of the capacity of sensory input to activate the CPGs when the continuity of the white matter tracts is impaired following spinal cord injury. Using electrophysiological recordings, confocal imaging studies of spinal neurons and surgical manipulations of the white matter, we show that the capacity of sacrocaudal afferent (SCA) input to produce locomotor activity in isolated rat spinal cords depends not only on long ascending pathways, but also on recruitment of sacral proprioneurons interposed between the second order neurons and the hindlimb CPGs. We argue that large heterogeneous populations of second-order and proprioneurons whose crossed and uncrossed axons project rostrally through the ventral, ventrolateral/lateral and dorsolateral white matter funiculi contribute to the generation of the rhythm by the stimulated sacrocaudal input. The complex organization and multiple projection patterns of these populations enable the sacrocaudal afferent input to activate the CPGs even if the white matter pathways are severely damaged. Further studies are required to clarify the mechanisms involved in SCA-induced locomotor activity and assess its potential use for the rescue of lost motor functions after spinal cord injury.

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Section: Discussionmentioning

confidence: 99%

Long and Short Multifunicular Projections of Sacral Neurons Are Activated by Sensory Input to Produce Locomotor Activity in the Absence of Supraspinal Control

Etlin¹,

Blivis²,

Ben-Zwi³

et al. 2010

J. Neurosci.

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“…If cerebellar plasticity plays a similar role in H-reflex conditioning, the mossy fiber input may not be sensory, since conditioning is not impaired by transecting the major ascending spinal cord pathways Wolpaw 1997, 2002). While the effect of transecting the portion of the ventral spinocerebellar tract that ascends on the contralateral side of the spinal cord (Yamada et al 1991;Tracey 1995) has not been studied, it appears more likely that the mossy fiber input is an efference copy of sensorimotor cortex output conveyed to the cerebellum by cortico-pontinecerebellar connections (Allen and Tsukahara 1974;Ruigrok and Cella 1995;Brodal and Bjaalie 1997;Schmahmann and Pandyat 1997). The climbing fiber input could originate from the lower probability of reward immediately after CST activity that incorrectly influences H-reflex size.…”

Section: The Contribution Of the Cerebellar Outputmentioning

confidence: 99%

Ablation of cerebellar nuclei prevents H-reflex down-conditioning in rats

Chen¹,

Wolpaw²

2005

Learn. Mem.

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While studies of cerebellar involvement in learning and memory have described plasticity within the cerebellum, its role in acquisition of plasticity elsewhere in the CNS is largely unexplored. This study set out to determine whether the cerebellum is needed for acquisition of the spinal cord plasticity that underlies operantly conditioned decrease in the H-reflex, the electrical analog of the spinal stretch reflex. Rats in which the cerebellar output nuclei dentate and interpositus (DIN) had been ablated were exposed for 50 d to the H-reflex down-conditioning protocol. DIN ablation, which in itself had no significant long-term effect on H-reflex size, entirely prevented acquisition of a smaller H-reflex. Since previous studies show that corticospinal tract (CST) transection also prevents down-conditioning while transection of the rubrospinal tract and other major descending tracts does not, this result implies that DIN output that affects cortex is essential for generation of the CST activity that induces the spinal cord plasticity, which is, in turn, directly responsible for the smaller H-reflex. The result extends the role of the cerebellum in learning and memory to include participation in induction of plasticity elsewhere in the CNS, specifically in the spinal cord. The cerebellum might simply support processes in sensorimotor cortex or elsewhere that change the spinal cord, or the cerebellum itself might undergo plasticity similar to that occurring with vestibulo-ocular reflex (VOR) or eyeblink conditioning. Activity-dependent plasticity, which is now known to occur throughout the CNS and through a variety of mechanisms, is presumed to underlie learning. However, the mechanistic relationships between this plasticity and learned behavioral changes remain largely obscure. The complexity and limited accessibility of the CNS, combined with the fact that even simple learning involves plasticity at multiple sites (Wolpaw and Lee 1989;Carrier et al. 1997;Cohen et al. 1997;Lieb and Frost 1997;Thompson et al. 1997;Whalen and Pearson 1997;Lisberger 1998;Garcia et al. 1999;Medina et al. 2000Medina et al. , 2002Hansel et al. 2001;King et al. 2001;Wolpaw and Tennissen 2001;Carey and Lisberger 2002; van Alphen and De Zeeuw 2002;Blazquez et al. 2003), makes it hard to trace the connections from specific experiences to specific occurrences of activity-dependent plasticity, and thence to specific behavioral changes (Wolpaw 2002). Efforts to do so use experimental models based on simple behaviors produced by defined and accessible neural circuitry.Two of these models, vestibulo-ocular reflex (VOR) plasticity and eyelid conditioning, reveal plasticity in the cerebellum and associated brainstem nuclei that underlies relatively rapid behavioral change (Kim and

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“…The origins and destinations of these tracts have been extensively studied in the cat (Matsushita et al, 1979;Grant et al, 1982;Yaginuma and Matsushita, 1989;Xu and Grant, 1994), the rat (Yamada et al, 1991;Matsushita and Gao, 1997;Matsushita, 1999), and the chick (Lakke, et al, 1986;Okado et al, 1987) using anterograde and retrograde labeling techniques. In all mammals, the ventral spinocerebellar tract (VSCT) sends its axons across the midline to ascend contralaterally into the cerebellum (reviewed in Xu and Grant, 1994).…”

Section: Introductionmentioning

confidence: 99%

Paths, elongation, and projections of ascending chick embryonic spinal commissural neurons after crossing the floor plate

Arakawa

Iwashita²,

Matsuzaki³

et al. 2008

Brain Research

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The paths of embryonic chick spinal commissural neurons originating from the lumbosacral (LS) 2 spinal segment and born around Hamburger-Hamilton stage (HH) 18 were observed by labeling the axons with an in ovo electroporation method designed to limit the electroporated area to ~ one somite length. After crossing the floor plate, these axons followed two major paths, one ventral and one dorsal, and a minor path running between the major ones. These axons reached the brachial region by HH28, passed through the cervical region at HH29, and entered the medullary area by HH30.The dorsal axons entered the developing cerebellum by HH33, crossed the midline again, and spread into the rostral-ipsilateral area of the developing cerebellum so that most of them were confined to lobules II-III by HH39. A small population of ventrally running axons turned to enter the cerebellum, and the rest entered the superior medullary velum between the cerebellum and the midbrain. The LS2-originating axons that ascended ipsilaterally into the cerebellum followed a single path, and their extension was delayed compared with that of the commissural axons. Some of the ipsilateral axons innervated the cerebellum; the rest entered the superior medullary velum. These direct observations of the formation of part of the spinocerebellar projections in chick will be a useful reference for future analyses of the underlying mechanisms.Section: Nervous System Development, Regeneration and Aging.

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Trajectory of spinocerebellar fibers passing through the inferior and superior cerebellar peduncles in the rat spinal cord: A study using horseradish peroxidase with pedunculotomy

Cited by 49 publications

References 42 publications

Long and Short Multifunicular Projections of Sacral Neurons Are Activated by Sensory Input to Produce Locomotor Activity in the Absence of Supraspinal Control

Long and Short Multifunicular Projections of Sacral Neurons Are Activated by Sensory Input to Produce Locomotor Activity in the Absence of Supraspinal Control

Ablation of cerebellar nuclei prevents H-reflex down-conditioning in rats

Paths, elongation, and projections of ascending chick embryonic spinal commissural neurons after crossing the floor plate

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