| Reference code: | PT/FB/BL-2004-084.02 |
| Location: | Arquivo PCA - Pasta 19/2004
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Title:
| 5.35 – Ascending pathways: Anatomy and physiology
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| Publication year: | 2008
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URL:
| http://www.sciencedirect.com/science/article/pii/B9780123708809001778
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| Abstract/Results: | ABSTRACT:
Nociceptive information traveling from the periphery in primary sensory neurons is transmitted to second-order neurons located at the spinal cord and cranial sensory nuclei. From this first relay, various pathways distribute nociceptive input through higher processing centers, so that pain is ultimately perceived in its multiple dimensions and adequate adaptive responses are generated. Although these ascending pathways are believed to terminate in the cortex with one or several relay stations in their way, the term ‘nociceptive ascending pathways’ is normally used in a restricted sense to designate the neuronal tracts that connect the spinal cord with supraspinal regions, each pathway being named from the brain area at which it terminates. About 20 nociceptive ascending pathways have been uncovered so far, which terminate at multiple sites, from the upper spinal cord up to the thelencephalon.
There are subtle differences between the various pathways as to the laminar location and morphology of the spinal neurons of origin, although the latter aspect has been addressed only sporadically. Data on the spinal location of the ascending tracts point to the lack of clear segregation in their way to the brain. As to their neurochemical architecture, our present knowledge is still scarce and thus far from allowing a neurochemical-based pathway characterization. The data collected on the response properties of the neurons of origin of most pathways do not reveal major differences between them. High-threshold, wide-dynamic-range, and low-threshold neurons always participate albeit in different proportions, and, whenever investigated, inputs from skin, viscera, and deep tissues converge onto the same pathway.
The multitude of ascending nociceptive pathways, together with the subtleness of the anatomical and physiological aspects that separate them as to their origin at the spinal cord, makes difficult to attribute a particular functional meaning to each one. A tentative way of unraveling the role of each pathway in nociceptive processing has been the elucidation of the connections established by the target. There is, however, a fundamental need to further investigate the functional specificity of each pathway and in which way the compound organization of the nociceptive system contributes to the processing of the various pain states.
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| Accessibility: | Document does not exist in file
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Language:
| eng
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Author:
| Lima, D.
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Document type:
| Book chapter
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Number of reproductions:
| 1
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Reference:
| Lima, D. (2008). 5.35 - Ascending Pathways: Anatomy and Physiology. In R. H. Masland, T. D. Albright, P. Dallos, D. Oertel, S. Firestein, G. K. Beauchamp, M. C. Bushnell, A. I. Basbaum, J. H. Kaas & E. P. Gardner (Eds.), The Senses: A Comprehensive Reference (pp. 477-526). New York: Academic Press. https://doi.org/10.1016/B978-012370880-9.00177-8
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| Indexed document: | Yes
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| Keywords: | Amygdala / Ascending system / Dorsal reticular nucleus / Globus pallidus / Hypothalamus / Infralimbic cortex / Nociceptive pathways / Nucleus tractus solitarii / Parabrachial nuclei / Periaqueductal gray / Rostral ventromedial medulla / Septal complex / Spinal cord / Thalamus / Ventrolateral reticular formation
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