Topic
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.
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TL;DR: The major aim of this study was to define the topography of descending motor cortical influences on the dorsal column nuclei of the rat by measuring the averaged evoked unit responses to the T-stimuli, and plotting them as a function of C-T intervals.
40 citations
TL;DR: It is suggested that cutaneous inputs from the hand and forelimb are critical to the integrity of functions such as reaching and grasping, and axon branches from peripheral afferents that terminate on neurons in the dorsal horn of the spinal cord are likely central to the functional recovery.
40 citations
TL;DR: With colchicine treatment, calcitonin gene-related peptide-like immunoreactive cells were found in more areas of the brain stem such as the abducens nucleus, parabigeminal nucleus, principal oculomotor nucleus, trochlear nucleus and central gray, along with the nuclei which had shown calcitonIn gene- related peptide immunoreactivity in the untreated animals.
40 citations
TL;DR: Anterograde labeling after pressure injections of lectin‐conjugated horseradish peroxidase in the pontomedullary tegmentum was very sparse within the dorsal column nuclei; labeling was dense, however, in the region immediately ventral to these nuclei.
Abstract: Neurons in the pontomedullary tegmentum have been proposed as a final common pathway subserving descending inhibition in the dorsal column nuclei. To investigate the anatomical substrate for these descending effects, brainstem projections to the cuneate nucleus of rats were studied with injections of lectin-conjugated horseradish peroxidase. In rats with iontophoretic tracer injections in this nucleus, many labeled neurons were detected near the injection site, especially ventral and caudal to it. Intrinsic reciprocal projections were observed after injections in caudal, middle, or rostral levels of the cuneate nucleus. Neurons were labeled in the red nucleus, in agreement with previous anatomical studies, and also in the trigeminal, vestibular, and cochlear nuclei. An ipsilateral dorsomedial group of neurons was labeled in the upper cervical segments and scattered neurons were also labeled bilaterally near the central canal. Sparse retrograde labeling in the tegmentum was focused in the lateral paragigantocellular nucleus and caudal raphe. Consistent with the retrograde experiments, anterograde labeling after pressure injections of lectin-conjugated horseradish peroxidase in the pontomedullary tegmentum was very sparse within the dorsal column nuclei; labeling was dense, however, in the region immediately ventral to these nuclei. These results confirm previous work indicating that the activity of cuneate neurons is modulated by brainstem sensory nuclei. However, it appears that direct projections to the cuneate nucleus from pontine and rostral medullary regions are sparser than previously suggested. The last link of a polysynaptic descending inhibitory pathway may include GABAergic neurons immediately adjacent to the dorsal column nuclei and/or intrinsic to these nuclei.
40 citations
TL;DR: The relative contribution from various cortical areas to different portions within the DCN‐complex has been investigated in cats with restricted cortical lesions and using the Fink‐Heimer technique.
Abstract: Cortical projections to the dorsal column nuclei (DCN) of cats arise from layer V pyramids throughout the sensorimotor cortex and also from the second somatosensory cortical area (SII). In this study, the relative contribution from various cortical areas to different portions within the DCN-complex has been investigated in cats with restricted cortical lesions and using the Fink-Heimer technique.
The sensorimotor cortex (areas 4, 3, 1, and 2) projects throughout most of the rostro-caudal extent of the gracile nucleus. Densest projections arise from the upper bank of the cruciate sulcus containing mainly the hindlimb region (area 4), from the medial wall of the posterior sigmoid gyrus (mainly area 3a) and terminate in the rostral as well as in the clusters regions of the gracile nucleus. The contribution of cortico-gracile projections from the hindlimb regions of areas 3b, 1 and 2 are much less conspicuous and terminate mainly in the rostral region of the nucleus. The nucleus z, the medullary relay for Ia fibers from the hindlimb, receives exceedingly sparse cortical projections. Dense projections to the cuneate n. arise from the cortical forelimb representation in the posterior sigmoid gyrus (areas 3a and 4) and laterally in the upper bank of the cruciate sulcus (area 4). The distribution pattern of cortical projections within the cuneate nucleus is however different from that within the gracile n. since (a) none of the lesioned cortical areas in the forelimb representation project to the clusters region, and (b) cortical projections terminate most densely in the base of the cuneate n., a medullary relay for Ia fibers from the forelimb. Sparse projections to the rostral region of the cuneate n. arise uniformly from all cytoarchitectonic areas of the forelimb representation. Cortical projections from SII are sparse and confined to the base and rostral region of the cuneate n.
The results provide further evidence for the origin of descending projections upon the DCN mainly from cortical regions related to movement control. Further, it is suggested that cortico-DCN control is biased toward nuclear subdivisions related to cutaneous afferents from the hindlimb within the gracile n.-nucleus Z complex but toward nuclear subdivisions related to deep and muscle afferents from the forelimb within the cuneate nucleus.
40 citations