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The efferent connections of the feline nucleus cuneatus

 

作者: Peter J. Hand,   Thomas Van Winkle,  

 

期刊: Journal of Comparative Neurology  (WILEY Available online 1977)
卷期: Volume 171, issue 1  

页码: 83-109

 

ISSN:0092-7317

 

年代: 1977

 

DOI:10.1002/cne.901710107

 

出版商: The Wistar Institute of Anatomy and Biology

 

数据来源: WILEY

 

摘要:

AbstractNucleus cuneatus projections to nucleus ventralis posterolateralis pars medialis (VPLm) and other thalamic as well as midbrain and medullary nuclei were studied in cats using the Fink‐Heimer I silver technique. Single electrolytic lesions of very small size were made stereotaxically in different zones of nucleus cuneatus under electrophysiological control. All zones studied projected to contralateral VPLm in a pattern of discrete terminal arborizations or clusters, which were organized in onionskin‐like dorso‐ventral laminae.The clusters of degeneration varied in size and density according to their dorsoventral location within VPLm. Those in dorsal areas were smaller in diameter (50–125 μ) and contained less dense amounts of degeneration than clusters (150–300 μ) in more ventral regions. The clustered terminal arborizations mirrored the organization of the VPLm neuronal clusters, themselves.Terminations within VPLm were topographically organized, but were completely inverted, i.e. dorsal nucleus cuneatus projected to ventral VPLm and ventral to dorsal, lateral to medial, and medial to lateral VPLm. A ventral zone of nucleus cuneatus, which contained “deep” units, projected to a separate dorsal zone of VPLm. In addition to its classical connection with VPLm, nucleus cuneatus projected to the following contralateral brainstem or thalamic nuclei: medial and dorsal accessory olives, external nucleus of the inferior colliculus, ventrolateral part of the superior colliculus, nucleus ruber, medial geniculate nucleus pars magnocellularis, suprageniculatus, medial and lateral divisions of the posterior thalamic nuclear group, zona incerta, and Fields of Forel. Very sparse amounts of degeneration were also present within nuclei ventralis posteromedialis (caudal pole) and ventralis posterolateralis pars lateralis. The brainstem and thalamic projections of the dorsocaudal part (cell nest region) of the cuneate nucleus were more restricted than those of its rostral and ventral regions. The clusters of both the VPLm neurons and cuneate terminations within VPLm provides an anatomical basis for the functional characteristics of synaptic security, fine grain somatotopia and modality specificity so prominent in the dorsal column nuclei‐medial

 

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