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.

HOD is caused by lesions in the dentatorubral or central tegmental tracts.

[3] Lesions involving this circuit may produce palatal myoclonus, one of the few involuntary movements that do not disappear during sleep.

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

The convergence of both components makes the combination of Holmes tremor and HOD after upper brainstem damage plausible and even likely.

Labeled diagram showing some of the cerebellar neural tracts. Only the nucleus ruber and the dentate nucleus are shown in this diagram; the olivary nucleus is positioned on the lateral aspect of the brainstem.
Palatal myoclonus