====== Triangle of Guillain and Mollaret ======


The triangle of Guillain and Mollaret, also known as the [[Dentato-Rubro-Olivary Tract]], has three corners:

[[red nucleus]]

[[inferior olivary nucleus]]

contralateral [[dentate nucleus]]

The [[Rubro-olivary tract]] fibers descend from the parvocellular division of each red nucleus along the [[central tegmental tract]]s to reach the capsule ([[amiculum olivare]]) of the ipsilateral inferior olivary nucleus (ION). From the ION, [[olivocerebellar tract]] fibers cross the contralateral [[inferior cerebellar peduncle]] to reach the [[cerebellar cortex]], then pass from the cerebellar cortex to the contralateral dentate nucleus. [[Dentatorubral fibers]] then ascend via the contralateral [[superior cerebellar peduncle]], decussate in the [[midbrain]], and return to the original [[red nucleus]]. 


Note that no direct connecting tract is present between the inferior olivary nucleus and contralateral dentate nucleus 
((Wein S, Yan B, Gaillard F. Hypertrophic olivary degeneration secondary to pontine haemorrhage. J Clin Neurosci. 2015 Jul;22(7):1213-4. doi: 10.1016/j.jocn.2015.02.005. Epub 2015 Apr 8. PMID: 25863998.)).

===== History and etymology =====

The [[Triangle of Guillain and Mollaret]] was described in [[1931]] by the French neurologists [[Georges Charles Guillain]] (1876-1961) and [[Pierre Mollaret]] (1898-1987) 
((Turgut AÇ, Tubbs RS, Turgut M. Georges Charles Guillain (1876-1961) and Pierre Mollaret (1898-1987) and their legacy to neuroanatomy: the forgotten triangle of Guillain-Mollaret. Childs Nerv Syst. 2021 Feb;37(2):349-350. doi: 10.1007/s00381-018-04033-8. Epub 2019 Jan 4. PMID: 30610482.))
((Guillain G, Mollaret P. Deux cas de myoclonies synchrones et rythmées vélo-pliaryngo-oculo-diaphragmatiques. Le problème anatomique et physio-pathologique de ce syndrome. Rev Neurol (Paris). 1931;2:545–566.))
They are also known respectively for defining what is now known as [[Guillain-Barré syndrome]] and [[Mollaret's meningitis]].

===== Related pathology =====
[[Hypertrophic olivary degeneration]], manifest as palatal myoclonus contralateral to lesions of the superior cerebellar peduncle
ipsilateral to lesions of the central tegmental tract
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[[Cerebellar atrophy]]
contralateral to lesions of the olivocerebellar fibers
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[[Holmes tremor]] (double lesions in both the dentatorubral-olivary system and dopaminergic nigrostriatal system)
((Raina GB, Cersosimo MG, Folgar SS, Giugni JC, Calandra C, Paviolo JP, Tkachuk VA, Zuñiga Ramirez C, Tschopp AL, Calvo DS, Pellene LA, Uribe Roca MC, Velez M, Giannaula RJ, Fernandez Pardal MM, Micheli FE. Holmes tremor: Clinical description, lesion localization, and treatment in a series of 29 cases. Neurology. 2016 Mar 8;86(10):931-8. doi: 10.1212/WNL.0000000000002440. Epub 2016 Feb 10. PMID: 26865524; PMCID: PMC4782118.))
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[[Myorhythmia]] is a hyperkinetic [[movement disorder]] that derives from a disruption of the [[Triangle of Guillain and Mollaret]], due to an identifiable structural lesion. It is often disabling and with disappointing control under medical treatment.