The nuclear masses in the cervical spinal cord of Macaca mulatta

Reed, Adrian F.

doi:10.1002/cne.900720107

Cited by 54 publications

(13 citation statements)

References 10 publications

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“…The observations of the present study extend Kuypers medial motor system concept in several notable ways. First was our finding of a topographically specific contralateral LPMCd CSP to the dorsomedial quadrant of lamina IX which is known to harbor proximal upper limb flexor motoneurons (Jenny & Inukai, ; Reed, ). This would suggest potential involvement in control of reaching.…”

Section: Discussionmentioning

confidence: 99%

Terminal organization of the corticospinal projection from the lateral premotor cortex to the cervical enlargement (C5–T1) in rhesus monkey

Morecraft

Stilwell-Morecraft

et al. 2019

J of Comparative Neurology

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High‐resolution tract tracing and stereology were used to study the terminal organization of the corticospinal projection (CSP) from the ventral (v) and dorsal (d) regions of the lateral premotor cortex (LPMC) to spinal levels C5–T1. The LPMCv CSP originated from the postarcuate sulcus region, was bilateral, sparse, and primarily targeted the dorsolateral and ventromedial sectors of contralateral lamina VII. The convexity/lateral part of LPMCv did not project below C2. Thus, very little LPMCv corticospinal output reaches the cervical enlargement. In contrast, the LPMCd CSP was 5× more prominent in terminal density. Bilateral terminal labeling occurred in the medial sectors of lamina VII and adjacent lamina VIII, where propriospinal neurons with long‐range bilateral axon projections reside. Notably, lamina VIII also harbors axial motoneurons. Contralateral labeling occurred in the lateral sectors of lamina VII and the dorsomedial quadrant of lamina IX, noted for harboring proximal upper limb flexor motoneurons. Segmentally, the CSP to contralateral laminae VII and IX preferentially innervated C5–C7, which supplies shoulder, elbow, and wrist musculature. In contrast, terminations in axial‐related lamina VIII were distributed bilaterally throughout all cervical enlargement levels, including C8 and T1. These findings demonstrate the LPMCd CSP is structured to influence axial and proximal upper limb movements, supporting Kuypers conceptual view of the LPMCd CSP being a major component of the medial motor control system. Thus, distal upper extremity control influenced by LPMC, including grasping and manipulation, must occur through indirect neural network connections such as corticocortical, subcortical, or intrinsic spinal circuits.

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Section: Discussionmentioning

confidence: 99%

Terminal organization of the corticospinal projection from the lateral premotor cortex to the cervical enlargement (C5–T1) in rhesus monkey

Morecraft

Stilwell-Morecraft

et al. 2019

J of Comparative Neurology

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“…Spinal root and spinal segment input to the radial nerve and several of its muscle branches has been studied in many species with a variety of techniques (SHERRINGTON, 1898;GOERING, 1928;MILLER, 1934;REED, 1940;ALLAM et al, 1952;STERLING and KUYPERS, 1967;BAULAC and MEININGER, 1979;JENNY and INUKAI, 1983;and FRITZ et al, 1986). As might be expected, there was considerable variation among species.…”

Section: Discussionmentioning

confidence: 99%

Spinal Root Origin of the Radial Nerve and Nerves Innervating Shoulder Muscles of the Dog

Sharp

Bailey

Johnson

et al. 1991

Anat Histol Embryol

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The ventral spinal root origin of the radial nerve, its muscle branches, and brachial plexus nerves which supply shoulder and thoracic musculature was determined in the dog. Electrophysiological signal averaging techniques measured evoked potential from specific ventral spinal roots to individual muscle nerves. The entire radial nerve received input from the sixth cervical (C6) through the second thoracic (T2) spinal roots. The most significant (p less than .05) input to triceps brachii came from C8 while the deep ramus of the radial nerve received its largest input from C7. The brachiocephalicus, suprascapular, and subscapular nerves all received their most significant (p less than .05) innervation from C6. Approximately 90% of the evoked potential to the axillary nerve originated from C7. The thoracodorsal nerve received most of its innervation from ventral roots C7 and C8. The lateral thoracic nerve which innervates the cutaneous trunci muscle was supplied by ventral roots C8-T2. Examination of innervation patterns suggests that only modest variation of spinal root input to specific nerves occurred between individual dogs.

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“…However, lower cervical segments also contain some motoneurons that innervate more proximal muscles like triceps and pectoralis (Jenny and Inukai, 1983). Furthermore, the medial cell column of motoneurons that innervates axial muscles extends throughout the cervical enlargement (Sherrington, 1898;Reed, 1940;Sprague, 1948;Kuypers, 198 1). A tracer injection into lower cervical segments would involve not only motoneurons innervating distal forelimb muscles, but also some motoneurons innervating more proximal injection sites.…”

Section: Topographic Organization Of the Corticospinal Systemmentioning

confidence: 99%

Topographic organization of corticospinal projections from the frontal lobe: motor areas on the lateral surface of the hemisphere

1993

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We examined the topographic organization of corticospinal neurons in the primary motor cortex and in the two premotor areas on the lateral surface of the hemisphere [i.e., the dorsal premotor area (PMd) and the ventral premotor area (PMv)]. In two macaques, we labeled corticospinal neurons that project beyond T7 or S2 by placing crystals of HRP into the dorsolateral funiculus at these segmental levels. In another seven macaques, we labeled corticospinal neurons that project to specific segmental levels of the spinal cord by injecting the fluorescent tracers fast blue and diamidino yellow into the gray matter of the cervical and lumbosacral segments. In one set of experiments (n = 2), we defined the representations of the arm and leg in each cortical motor area by injecting one of the two fluorescent tracers into lower cervical segments (C7-T1) and the other fluorescent tracer into lower lumbosacral segments (L6-S1) of the same animal. In another set of experiments (n = 5), we defined the representations of distal and proximal parts of the forelimb in each cortical motor area by injecting one of the two fluorescent tracers into lower cervical segments (C7-T1) and the other tracer into upper cervical segments (C2-C4) of the same animal. In the primary motor cortex and the PMd, cortical regions that project to lower cervical segments were largely separate from those that project to lower lumbosacral segments. In the PMv, few neurons were labeled after tracer injections into lower cervical segments or lower lumbosacral segments. However, corticospinal neurons were labeled in the PMv after tracer injections into upper cervical segments and after HRP placement in the dorsolateral funiculus at T7. The region of the PMv that projects to upper cervical segments was separate from that which projects below T7. Cortical regions that project to upper and lower cervical segments of the spinal cord overlapped considerably in the primary motor cortex and in the PMd. Despite this overlap, we found that the regions of the primary motor cortex and PMd that project most densely to upper cervical segments were largely separate from those that project most densely to lower cervical segments. Furthermore, we found two separate regions within area 4 that send corticospinal projections primarily to the lower cervical segments. One of these regions was located within the classical "hand" area of the primary motor cortex. The other was located at the medial edge of arm representation in the primary motor cortex.(ABSTRACT TRUNCATED AT 400 WORDS)

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The nuclear masses in the cervical spinal cord of Macaca mulatta

Cited by 54 publications

References 10 publications

Terminal organization of the corticospinal projection from the lateral premotor cortex to the cervical enlargement (C5–T1) in rhesus monkey

Terminal organization of the corticospinal projection from the lateral premotor cortex to the cervical enlargement (C5–T1) in rhesus monkey

Spinal Root Origin of the Radial Nerve and Nerves Innervating Shoulder Muscles of the Dog

Topographic organization of corticospinal projections from the frontal lobe: motor areas on the lateral surface of the hemisphere

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