Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (decussis), from Latin decem 'ten', and as 'as'). In Latin anatomical terms, the form decussatio is used, e.g. decussatio pyramidum.
Section of the medulla oblongata at the level of the decussation of the pyramids
Similarly, the anatomical term chiasma is named after the Greek uppercase 'Χ' (chi). Whereas a decussation refers to a crossing within the central nervous system, various kinds of crossings in the peripheral nervous system are called chiasma.
Examples include:
In the brain, where nerve fibers obliquely cross from one lateral side of the brain to the other, that is to say they cross at a level other than their origin. See for examples decussation of pyramids and sensory decussation. In neuroanatomy, the term chiasma is reserved for crossing of- or within nerves such as in the optic chiasm.
In botanicalleaf taxology, the word decussate describes an opposite pattern of leaves which has successive pairs at right angles to each other (i.e. rotated 90 degrees along the stem when viewed from above). In effect, successive pairs of leaves cross each other. Basil is a classic example of a decussate leaf pattern. Decussate phyllotaxis of Crassula rupestris
In tooth enamel, where bundles of rods cross each other as they travel from the enamel-dentine junction to the outer enamel surface, or near to it.
In taxonomic description where decussate markings or structures occur, names such as decussatus or decussata or otherwise in part containing "decuss..." are common, especially in the specific epithet.[1]
The origin of the contralateral organization, the optic chiasm and the major decussations on the nervous system of vertebrates has been a long standing puzzle to scientists.[2] The visual map theory of Ramón y Cajal has long been popular[3][4] but has been criticized for its logical inconsistence.[5] More recently, it has been proposed that the decussations are caused by an axial twist by which the anterior head, along with the forebrain, is turned by 180° with respect to the rest of the body.[6][7]
^Vulliemoz, S.; Raineteau, O.; Jabaudon, D. (2005). "Reaching beyond the midline: why are human brains cross wired?". The Lancet Neurology. 4 (2): 87–99. doi:10.1016/S1474-4422(05)00990-7. PMID 15664541. S2CID 16367031.
^Ramón y Cajal, Santiago (1898). "Estructura del quiasma óptico y teoría general de los entrecruzamientos de las vías nerviosas. (Structure of the Chiasma opticum and general theory of the crossing of nerve tracks)" [Die Structur des Chiasma opticum nebst einer allgemeine Theorie der Kreuzung der Nervenbahnen (German, 1899, Verlag Joh. A. Barth)]. Rev. Trim. Micrográfica (in Spanish). 3: 15–65.
^Llinás, R.R. (2003). "The contribution of Santiago Ramón y Cajal to functional neuroscience". Nat. Rev. Neurosci. 4 (1): 77–80. doi:10.1038/nrn1011. PMID 12511864. S2CID 30442863.
^de Lussanet, M.H.E.; Osse, J.W.M. (2015). (PDF). Neuropsychology. 29 (5): 713–14. doi:10.1037/neu0000163. PMID 25528610. Archived from the original (PDF) on 2021-07-14. Retrieved 2020-01-01.
^de Lussanet, M.H.E.; Osse, J.W.M. (2012). "An ancestral axial twist explains the contralateral forebain and the optic chiasm in vertebrates". Animal Biology. 62 (2): 193–216. arXiv:1003.1872. doi:10.1163/157075611X617102. S2CID 7399128.
^Kinsbourne, M (Sep 2013). "Somatic twist: a model for the evolution of decussation". Neuropsychology. 27 (5): 511–15. doi:10.1037/a0033662. PMID 24040928.
Further readingedit
Why does the nervous system decussate?: Stanford Neuroblog
Fields, R. Douglas (2023-04-19). "Why the Brain's Connections to the Body Are Crisscrossed". Quanta Magazine.
External linksedit
Media related to Decussation at Wikimedia Commons
January 01, 1970
decussation, confused, with, desiccation, chiasm, anatomy, commissure, used, biological, contexts, describe, crossing, shape, roman, numeral, uppercase, decussis, from, latin, decem, latin, anatomical, terms, form, decussatio, used, decussatio, pyramidum, sect. Not to be confused with Desiccation Chiasm anatomy or Commissure Decussation is used in biological contexts to describe a crossing due to the shape of the Roman numeral for ten an uppercase X decussis from Latin decem ten and as as In Latin anatomical terms the form decussatio is used e g decussatio pyramidum Section of the medulla oblongata at the level of the decussation of the pyramids Similarly the anatomical term chiasma is named after the Greek uppercase X chi Whereas a decussation refers to a crossing within the central nervous system various kinds of crossings in the peripheral nervous system are called chiasma Examples include In the brain where nerve fibers obliquely cross from one lateral side of the brain to the other that is to say they cross at a level other than their origin See for examples decussation of pyramids and sensory decussation In neuroanatomy the term chiasma is reserved for crossing of or within nerves such as in the optic chiasm In botanical leaf taxology the word decussate describes an opposite pattern of leaves which has successive pairs at right angles to each other i e rotated 90 degrees along the stem when viewed from above In effect successive pairs of leaves cross each other Basil is a classic example of a decussate leaf pattern Decussate phyllotaxis of Crassula rupestris In tooth enamel where bundles of rods cross each other as they travel from the enamel dentine junction to the outer enamel surface or near to it In this true bug Dysdercus decussatus in the family Pyrrhocoridae the specific epithet refers to the bandolier like markings on the back In taxonomic description where decussate markings or structures occur names such as decussatus or decussata or otherwise in part containing decuss are common especially in the specific epithet 1 Contents 1 Evolutionary significance 2 See also 3 References 4 Further reading 5 External linksEvolutionary significance editThe origin of the contralateral organization the optic chiasm and the major decussations on the nervous system of vertebrates has been a long standing puzzle to scientists 2 The visual map theory of Ramon y Cajal has long been popular 3 4 but has been criticized for its logical inconsistence 5 More recently it has been proposed that the decussations are caused by an axial twist by which the anterior head along with the forebrain is turned by 180 with respect to the rest of the body 6 7 See also editDefinition of types of crossings Palpebral commissure of the eye Commissure Chiasm Contralateral brain Fissure anatomy References edit Jaeger Edmund C 1959 A source book of biological names and terms Springfield Ill Thomas ISBN 0 398 06179 3 Vulliemoz S Raineteau O Jabaudon D 2005 Reaching beyond the midline why are human brains cross wired The Lancet Neurology 4 2 87 99 doi 10 1016 S1474 4422 05 00990 7 PMID 15664541 S2CID 16367031 Ramon y Cajal Santiago 1898 Estructura del quiasma optico y teoria general de los entrecruzamientos de las vias nerviosas Structure of the Chiasma opticum and general theory of the crossing of nerve tracks Die Structur des Chiasma opticum nebst einer allgemeine Theorie der Kreuzung der Nervenbahnen German 1899 Verlag Joh A Barth Rev Trim Micrografica in Spanish 3 15 65 Llinas R R 2003 The contribution of Santiago Ramon y Cajal to functional neuroscience Nat Rev Neurosci 4 1 77 80 doi 10 1038 nrn1011 PMID 12511864 S2CID 30442863 de Lussanet M H E Osse J W M 2015 Decussation as an axial twist A comment on Kinsbourne 2013 PDF Neuropsychology 29 5 713 14 doi 10 1037 neu0000163 PMID 25528610 Archived from the original PDF on 2021 07 14 Retrieved 2020 01 01 de Lussanet M H E Osse J W M 2012 An ancestral axial twist explains the contralateral forebain and the optic chiasm in vertebrates Animal Biology 62 2 193 216 arXiv 1003 1872 doi 10 1163 157075611X617102 S2CID 7399128 Kinsbourne M Sep 2013 Somatic twist a model for the evolution of decussation Neuropsychology 27 5 511 15 doi 10 1037 a0033662 PMID 24040928 Further reading editWhy does the nervous system decussate Stanford Neuroblog Fields R Douglas 2023 04 19 Why the Brain s Connections to the Body Are Crisscrossed Quanta Magazine External links edit nbsp Media related to Decussation at Wikimedia Commons Retrieved from https en wikipedia org w index php title Decussation amp oldid 1198282095, wikipedia, wiki, book, books, library,
