Myoclonic triangle
The myoclonic triangle (also known by its eponym Triangle of Guillain-Mollaret or dentato-rubro-olivary pathway) is an important feedback circuit of the brainstem and deep cerebellar nuclei which is responsible for modulating spinal cord motor activity.[1][2]
The circuit is thus composed:[2]
- Fibers of the rubro-olivary tract project from the parvocellular red nucleus via the central tegmental tract to the ipsilateral inferior olivary nucleus.
- The inferior olivary nucleus sends its afferents via climbing fibers in the inferior cerebellar peduncle to Purkinje cells of the contralateral cerebellar cortex.
- The Purkinje cells send their afferents to the ipsilateral dentate nucleus.
- Dentatorubral tract fibers: the dentate nucleus afferents travel via the superior cerebellar peduncle to the contralateral red nucleus, thus completing the circuit.
Of note, this circuit contains a double decussation, implying that a lesion in this tract will cause ipsilateral symptoms.
The descending rubrospinal tract and reticulospinal tract originate in the red nucleus and reticular formation (which is closely associated with the central tegmental tract) respectively, thereby providing the mechanism by which this circuit exerts its effects on spinal cord motor activity.
- ^ Murdoch, Sheena; Shah, Pushkar; Jampana, Ravi (June 2016). "The Guillain-Mollaret triangle in action". Practical Neurology. 16 (3): 243–246. doi:10.1136/practneurol-2015-001142. ISSN 1474-7766. PMID 26740379. S2CID 207025040.
- ^ a b Lavezzi, Anna Maria; Corna, Melissa; Matturri, Luigi; Santoro, Franco (2009-07-01). "Neuropathology of the Guillain-Mollaret Triangle (Dentato-Rubro-Olivary Network) in Sudden Unexplained Perinatal Death and SIDS". The Open Neurology Journal. 3 (1): 48–53. doi:10.2174/1874205X00903010048. ISSN 1874-205X. PMC 2708385. PMID 19597559.