Myoclonic triangle

Anatomical region in the brainstem

Myoclonic Triangle

The myoclonic triangle, also known as the Guillain-Mollaret triangle, is a neural circuit in the brainstem that is involved in the coordination of movement and is associated with certain types of tremors and myoclonus. This anatomical structure is named after the French neurologists Georges Guillain and Pierre Mollaret.

Illustration of the brainstem showing the location of the myoclonic triangle.

Anatomy

The myoclonic triangle is composed of three main structures:

• The dentate nucleus of the cerebellum
• The red nucleus in the midbrain
• The inferior olivary nucleus in the medulla oblongata

These structures are interconnected by neural pathways that form a triangular circuit. The dentate nucleus sends projections to the red nucleus via the superior cerebellar peduncle. The red nucleus, in turn, projects to the inferior olivary nucleus through the central tegmental tract. Finally, the inferior olivary nucleus sends climbing fibers back to the cerebellum, completing the circuit.

Function

The myoclonic triangle is involved in the coordination of voluntary movements and the modulation of motor activity. It plays a crucial role in the timing and precision of movements, and its dysfunction can lead to motor disorders. The circuit is particularly associated with the generation of palatal myoclonus, a condition characterized by rhythmic contractions of the muscles of the palate.

Clinical Significance

Disruptions in the myoclonic triangle can lead to a variety of neurological symptoms. Lesions affecting any part of this circuit can result in myoclonus, tremor, or other movement disorders. The most well-known condition associated with the myoclonic triangle is palatal myoclonus, which can occur due to lesions in the central tegmental tract or the inferior olivary nucleus.

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Related Pages

• Cerebellum
• Red nucleus
• Inferior olivary nucleus
• Palatal myoclonus
• Movement disorders