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Introduction: Background Material
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
A peripheral nerve or simply a nerve is a cable-like bundle of nerve fibers in the peripheral nervous system. A fiber tract, or a tract, is a bundle of nerve fibers in the central nervous system. A nerve fascicle, or fascicle, is a small fiber tract whose nerve fibers have similar origin, termination, and function. A bundle of one or more nerve fascicles is a funiculus.
Neurotrophic Factors
Published in Martin Berry, Ann Logan, CNS Injuries: Cellular Responses and Pharmacological Strategies, 2019
Recent advances in research on spinal cord degeneration and regeneration have been extensively reviewed elsewhere.168 The primary peripheral sensory neurons project one of their fibers peripherally through the nerve and one through the dorsal root to the cord, where they terminate and/or form the ascending sensory tract of the dorsal column system (Figure 9.2, A). This tract lies in the dorsal funiculus making it very accessible for experimental manipulations. After injury of either or both of their processes, adult sensory neurons do not die and their axons can regenerate very well in the peripheral nerve and the dorsal root and to a lesser extent into peripheral nerve and fetal grafts placed into the lesioned spinal cord. However, such adult regenerating fibers fail to reenter the cord more than ∼1 mm, again emphasizing the nonpermissive nature of the CNS.168–170 Of particular interest to sensory regeneration (as well as for other neurons) is the finding that regeneration of the central projecting axon into peripheral nerve grafts is greatly enhanced by or even dependent on a previous conditioning lesion of the peripheral sensory projections.171–173 The mechanism of this so-called “conditioning lesion” apparently involves the inflammatory response and satellite cell proliferation in the ganglion174–176 and could very well be initiated by cytokines released from the injured neurons.177 The understanding of how this conditioning can be achieved in the CNS will be a major advance toward resolving the problem of CNS regeneration.
The Spinal Cord and the Spinal Canal
Published in Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand, Pediatric Regional Anesthesia, 2019
Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand
The white matter surrounds the gray matter. It consists of nerve fibers arranged in three funiculi or white columns (Figure 1.18): posterior, lateral, and anterior (the last two funiculi cannot easily be separated and are often considered as a single funiculus termed as funiculus anterolateralis). Anterior to the anterior gray commissure is a bundle of transverse fibers originating in the gray substance and called the anterior white commissure (commissura alba).
PU.1 interaction with p50 promotes microglial-mediated inflammation in secondary spinal cord injury in SCI rats
Published in International Journal of Neuroscience, 2023
Mingchen Yu, Yiqing Ou, Hongmei Wang, Weidong Gu
The number of PU.1-positive cells on the spinal cord sections taken at 2 mm from the injury epicenter was counted in 500 × 500 μm frames. For each animal, the transverse sections of the dorsal horn, lateral funiculus, and ventral horn were selected. The cell counts were then used to determine the total number of PU.1-positive cells per square millimeter. The percentage of cells that stained positive for PU.1 or p-p50 was also quantified. The cells double stained with PU.1 and NeuN, GFAP, or Iba-1, as well as cells double stained with PU.1 and OX42 or p-p50, were also quantified. To identify the proportion of PU.1-expressing cells with positive expression of specific phenotypic markers, a minimum of 200 cells positive for the specific phenotypic markers in the white and gray matter of the sections were included. We then recorded the number of cells double-labeled with PU.1 and cell-specific markers. Two or three adjacent sections taken at 2 mm from the injury epicenter were used for quantitative analysis.
Selection of preferred thermal environment and cold-avoidance responses in rats rely on signals transduced by the dorsal portion of the lateral funiculus of the spinal cord
Published in Temperature, 2023
Robson C.L. Vizin, Maria C. Almeida, Renato N. Soriano, Andrej A. Romanovsky
The neural pathways mediating most thermoregulatory behaviors, including the selection of Tpr, are not fully established [2]. Yahiro et al. [15] reported that the inactivation of neurons in the lateral parabrachial nucleus (LPB) suppressed innocuous cold- and warmth-avoidance behaviors in rats. This finding agrees with our results (M. C. Almeida and A. A. Romanovsky, unpublished observation; reviewed in Ref. [2]) showing that bilateral electrolytic lesioning of the LPB attenuated warmth-seeking response to cold exposure in rats in a thermogradient apparatus. It has also been thoroughly documented that the LPB is involved in pathways controlling physiological thermoeffectors, and that it receives thermal information from the periphery, including the skin, through the spinoparabrachial tract [16]. The latter ascends in the spinal cord within the dorsal portion of the lateral funiculus, which we refer to in this paper as the dorsolateral funiculus (DLF) (reviewed in Refs. [17,18]).
Spinal cord involvement in Lewy body-related α-synucleinopathies
Published in The Journal of Spinal Cord Medicine, 2020
Raffaele Nardone, Yvonne Höller, Francesco Brigo, Viviana Versace, Luca Sebastianelli, Cristina Florea, Kerstin Schwenker, Stefan Golaszewski, Leopold Saltuari, Eugen Trinka
In an autoptic study, by means of α-synuclein immunohistochemistry and lipofuscin pigment-Nissl architectonics the brains and spinal cords of 28 patients with clinically and neuropathologically confirmed PD, 6 cases with ILBD, and 12 age-matched controls have been investigated. LBAS (particulate aggregations, LNs/LBs) in the spinal cord were observed between neuropathological stages 2–6 in all cases whose brains were staged for PD-LBAS40 (Fig. 4). Only individuals with ILBD and all controls did not have Lewy pathology. The PD-related lesions were found in the spinal cord only after Lewy pathology was observed in the brain. It can therefore be supposed that, within the central nervous system, sporadic PD does not begin in the spinal cord. α-synuclein-immunoreactive axons were clearly predominant over LBs throughout the spinal cord and were observed in medial and anterior portions of the anterolateral funiculus. They formed dense α-synuclein-immunoreactive networks in the gray matter and were most remarkable in the lateral portions of layers 1, 7, and in the cellular islands of layer 9. The density of these axonal lesions increased markedly in from cervicothoracic segments to lumbosacral segments of the cord. The spinal cord α-synuclein immunoreactive axonal networks might represent descending projections from the supraspinal level setting nuclei (locus coeruleus, lower raphe nuclei, magnocellular portions of the reticular formation).