Lesions in Mollaret’s triangle (Guillain Mollaret triangle) classically cause palatal myoclonus or “oculopalatal” myoclonus involving both the palate and the eyes. 

The nystagmus in oculopalatal myoclonus can be vertical, horizontal, or torsional, and is often pendular. The palatal tremor can often be noticed by patients as hearing a “clicking sound” 

Mollaret’s triangle consists of the inferior olivary nucleus of the medullar, the red nucleus of the tegmentum of the midbrain, and the contralateral nucleus in the cerebellum. 
– pathways connecting the points of the triangle pass through the inferior and superior cerebellar peduncles

A lesion anywhere in the triangle will often cause T2 hyperintensity seen in the inferior olive secondary to compensatory hypertrophy 
– usually seen on MRI after 4 weeks of symptoms 

 

The red nucleus is located in the dorsal midbrain tegmentum near the substantia nigra, not the superior colliculus of the midbrain