Projections from the upper lumbar cord to the cerebellar nuclei in the rat, studied by anterograde axonal tracing

Abstract

The spinocerebellar tracts arising from the upper lumbar cord consist of the dorsal and the ventral spinocerebellar tracts (DSCT and VSCT), which ascend ipsilaterally and contralaterally, respectively. By using anterograde labeling with biotinylated dextran in the rat, this study examined whether the lumbar DSCT and the VSCT project to the cerebellar nuclei. Injections of the tracer were made unilaterally at levels between the L1 and L3 segments, with diffusion to either a rostral or a caudal segment. The injections resulted in bilateral labeling of axon terminals in the cerebellar nuclei. In the medial nucleus, labeled terminals were distributed in medial, ventral, and ventrolateral parts of the middle subdivision and ventral parts of the caudomedial subdivision. In the anterior interpositus nucleus, they were distributed in medial and dorsomedial parts throughout the rostrocaudal extent. Labeled terminals were seen within the dorsomedial crest region. In the posterior interpositus nucleus, labeled terminals were seen in the rostromedial extension, the caudomedial part, and the caudal pole. Labeled terminals were seen in the hilus and the ventral part of the lateral nucleus. Projections of the DSCT and the VSCT to these regions were confirmed after tracer injections preceded by sectioning of either tract. Both tracts projected bilaterally, but the DSCT projected mainly ipsilaterally. The present study suggests that the spinocerebellar tracts originating from the upper lumbar cord (the lumbar DSCT and the VSCT) project to specific areas of the cerebellar nuclei to transmit information about the peripheral and central events during the movement of hindlimbs. J. Comp. Neurol. 412:633–648, 1999. © 1999 Wiley‐Liss, Inc.

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

“…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).…”

“…The connections of the commissural neurons innervating the cerebellum observed here matched those of the VSCT observed in mammals (reviewed in Xu and Grant, 1994;Matsushita, 1999). The VSCT is a crossed ascending tract, located in the ventrolateral spinal cord.…”

Spinal cord projections to the cerebellum in the mouse

“…The dorsal spinocerebellar tract originates from the large neurons of the dorsal nucleus (also named the Clarke's column) and laminae 4-6, starting from the third lumbar spinal cord segment (L3) to upper thoracic segments (Matsushita and Ikeda 1980;Grant et al 1982;Edgley and Gallimore 1988;Rivero-Melián and Grant 1990). The dorsal spinocerebellar tract projections are predominantly ipsilateral, but contralateral projections also exist (Xu and Grant 1994;Matsushita and Gao 1997;Matsushita 1999). The ventral spinocerebellar tract mainly originates from the medial part of lamina 7 in the lumbosacral segments, but also from the neurons of the ventrolateral nucleus of lamina 9 and the lateral part of lamina 7 at L4-L5 segments (Xu and Grant 2005).…”

“…Mossy fiber terminals of neurons in the cervical enlargement are observed in the anterior (i.e., lobules 1-5) and posterior vermis (i.e., lobules 7b and 8, and the most anterior part of the lobule 6), as well as the ipsilateral paramedian lobule in the cat (Wiksten and Grant 1986;Matsushita and Ikeda 1987). Terminals of neurons in the thoracic spinal cord are found mainly to the vermis of lobules 2b-5b in the rat (Matsushita and Gao 1997) and cat (Yaginuma and Matsushita 1987), and terminals of lumbar and sacrococcygeal neurons to the vermis of lobules 1-5 of the rat (Matsushita 1999) and cat (Matsushita 1988;Matsushita and Yaginuma 1989;Xu and Grant 1990). About 90 % of the labeled precerebellar neurons in the lower lumbar and sacrococcygeal segments project to the midline anterior lobe (Matsushita 1988).…”

Gene transfer of human acid sphingomyelinase corrects neuropathology and motor deficits in a mouse model of Niemann-Pick type A disease

“…In addition to being highly connected with the cerebellar cortex (i.e., major terminal projection site of Purkinje cells), the DCN is also connected with a number of central sites including the pons, medulla, and spinal cord (9)(10)(11)(12)(13). We anticipate that targeting the DCN with AAV vectors capable of axonal transport will result in widespread enzyme distribution throughout the cerebellum and possibly additional regions of the CNS.…”