The myoclonic triangle is an important feedback circuit of the brainstem and deep cerebellar nuclei which is responsible for modulating spinal cord motor activity.

The circuit is thus composed:

1. Fibers of the rubro-olivary tract
   Rubro-olivary tract
   The rubro-olivary tract is a tract which connects the inferior olive and the parvocellular red nucleus.It is hypothesized that it uses both the corticospinal tract and rubrospinal tract.-External links:...
   
    project from the parvocellular red nucleus
   Parvocellular red nucleus
   The parvocellular red nucleus is located in the rostral midbrain and is involved in motor coordination. Together with the magnocellular red nucleus, it makes up the red nucleus....
   
    via the central tegmental tract
   Central tegmental tract
   The central tegmental tract is a structure in the midbrain and pons.* The central tegmental tract includes ascending axonal fibers that arise from the caudal nucleus solitarius and terminate in the ventral posteromedial nucleus of thalamus...
   
    to the ipsilateral inferior olivary nucleus
   Inferior olivary nucleus
   The inferior olivary nucleus is the largest nucleus situated in the olivary body, part of the medulla oblongata.-Function:It is closely associated with the cerebellum, meaning that it is involved in control and coordination of movements, sensory processing and cognitive tasks likely by encoding the...
   
   .
2. The inferior olivary nucleus sends its afferents via climbing fibers in the inferior cerebellar peduncle
   Inferior cerebellar peduncle
   The upper part of the posterior district of the medulla oblongata is occupied by the inferior cerebellar peduncle , a thick rope-like strand situated between the lower part of the fourth ventricle and the roots of the glossopharyngeal and vagus nerves.Each cerebellar inferior peduncle connects the...
   
    to Purkinje cells of the contralateral cerebellar cortex.
3. The Purkinje cells send their afferents to the ipsilateral dentate nucleus
   Dentate nucleus
   The dentate nucleus is located within the deep white matter of each cerebellar hemisphere, and it is the largest single structure linking the cerebellum to the rest of the brain. It is the largest and most lateral, or farthest from the midline, of the four pairs of deep cerebellar nuclei, the...
   
   .
4. The dentate nucleus afferents travel via the superior cerebellar peduncle to the contralateral red nucleus, thus completing the cycle.

Of note, this circuit contains a double decussation, implying that a lesion in this tract will cause ipsilateral symptoms.

The descending rubrospinal tract

Rubrospinal tract

The rubrospinal tract is a part of the nervous system. It is a part of the lateral indirect extra-pyramidal tract.-Function:In humans, the rubrospinal tract is one of several major motor control pathways. It is smaller and has fewer axons than the corticospinal tract, suggesting that it is less...

 and reticulospinal tract

Reticulospinal tract

The reticulospinal tract is an extrapyramidal motor tract which travels from the reticular formation.-Functions:...

 originate in the red nucleus and reticular formation

Reticular formation

The reticular formation is a part of the brain that is involved in actions such as awaking/sleeping cycle, and filtering incoming stimuli to discriminate irrelevant background stimuli...

 (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.

Lesions involving this circuit may produce palatal myoclonus

Palatal myoclonus

Palatal myoclonus is a rapid spasm of the palatal muscles, which results in clicking or popping in the ear. Chronic clonus is often due to lesions of the central tegmental tract...

, one of the few involuntary movements that do not disappear during sleep. Palatal myoclonus may be seen as a component of the lateral medullary syndrome

Lateral medullary syndrome

Lateral medullary syndrome is a disease in which the patient has a constellation of neurologic symptoms due to injury to the lateral part of the medulla in the brain, resulting in tissue ischemia and necrosis.-Signs and symptoms:This syndrome is characterized by sensory deficits affecting...

(a.k.a. Wallenberg Syndrome), if the infarction extends to involve the central tegmental tract.