Cuneate nucleus

About: Cuneate nucleus is a research topic. Over the lifetime, 614 publications have been published within this topic receiving 24859 citations. The topic is also known as: cuneate nucleus of spinal cord.

Distribution of external cuneate nucleus afferents to the cerebellum: II. Topographical distribution and zonal pattern-an experimental study with radioactive tracers in the cat

Abstract: Small injections of tritiated leucine and the autoradiographic method were used to demonstrate efferents from restricted portions of the external cuneate nucleus (NCE) to the cerebellum. Sites of injection were analyzed by reference to the distribution of primary muscle afferents in NCE. On transverse sections, the silver deposits form longitudinal bands that, in certain regions, are packed together and label the entire surface of the granular layer; in other parts, they are separated by empty longitudinal bands. The longitudinal deposits are not continuous in the rostrocaudal direction. On the basis of the distribution of the longitudinal bands, 14 zones have been described for lobules II-VI, and 6 zones were recognized in lobules I, VIII, and the paramedian lobule. Afferents from NCE are distributed topographically. Regions of the nucleus receiving axial and neck muscles project mainly to vermal regions of lobules I-III, and to parts of lobules VIII and IX. Regions receiving afferents from forelimb muscles send their fibers preferentially to the vermian region of lobule V, to paravermian regions of lobules IV-VI, to parts of lobules VIII and IX, and to the paramedian lobule. These distributions in several respects are in agreement with the somatotopical maps of the cerebellum. However, other features support a "mosaic" arrangement: efferents from a region of NCE are distributed over several distinct sites of the cortex and efferents from different parts of the nucleus also converge to neighboring cortical regions.

Glossopharyngeal and vagal afferent projections to the brain stem of the cat: A horseradish peroxidase study

Abstract: Brain stem projections of the glossopharyngeal and vagus nerves in the cat were studied using the anterograde transport of horseradish peroxidase (HRP). Crystalline HRP was applied to the proximal cut ends of the nerves for a period of 4–10.5 h, and after a survival time of 24–120 h, transverse and horizontal sections of the brain stem were processed according to the tetramethylbenzidine method. Labeled fibers from both nerves were found to project bilaterally to the solitary complex, and ipsilaterally to the ventral region of the external cuneate nucleus and to the medial region of the nucleus praepositus hypoglossi, just dorsolateral to the medial longitudinal fasciculus. Within the solitary complex terminal labeling was found in the parvocellular, ventrolateral, lateral, medial and commissural solitary nuclei. Exclusive glossopharyngeal nerve projections were found ipsilaterally in the rostral dorsal motor nucleus of the vagus, the ventrolateral portion of the medial cuneate nucleus, the dorsal part of the nuclei caudalis and interpolaris of the trigeminal complex, the nuclei insulae cuneati lateralis, and the dorsolateral aspect of the nucleus medullae oblongata centralis. Finally, in the area postrema a bilateral projection of vagal and an ipsilateral projection of glossopharyngeal fibers were found. These findings demonstrate that the glossopharyngeal nerve has more widely distributed brain stem projections than the vagus nerve and provide essential information on projection sites of visceral and taste inputs to the central nervous sytem.

Ascending projections from the area around the spinal cord central canal: A Phaseolus vulgaris leucoagglutinin study in rats.

Abstract: A single small iontophoretic injection of Phaseolus vulgaris leucoagglutinin labels projections from the area surrounding the spinal cord central canal at midthoracic (T6-T9) or lumbosacral (L6-S1) segments of the spinal cord. The projections from the midthoracic or lumbosacral level of the medial spinal cord are found: 1) ascending ipsilaterally in the dorsal column near the dorsal intermediate septum or the midline of the gracile fasciculus, respectively; 2) terminating primarily in the dorsal, lateral rim of the gracile nucleus and the medial rim of the cuneate nucleus or the dorsomedial rim of the gracile nucleus, respectively; and 3) ascending bilaterally with slight contralateral predominance in the ventrolateral quadrant of the spinal cord and terminating in the ventral and medial medullary reticular formation. Other less dense projections are to the pons, midbrain, thalamus, hypothalamus, and other forebrain structures. Projections arising from the lumbosacral level are also found in Barrington's nucleus. The results of the present study support previous retrograde tract tracing and physiological studies from our group demonstrating that the neurons in the area adjacent to the central canal of the midthoracic or lumbosacral level of the spinal cord send long ascending projections to the dorsal column nucleus that are important in the transmission of second-order afferent information for visceral nociception. Thus, the axonal projections through both the dorsal and the ventrolateral white matter from the CC region terminate in many regions of the brain providing spinal input for sensory integration, autonomic regulation, motor and emotional responses, and limbic activation.