Downbeat nystagmus associated with damage to the medial longitudinal fasciculus of the pons: A vestibular balance control mechanism via the lower brainstem paramedian tract neurons

From the pathogenesis of this vertical vestibular nystagmus, the action of the PMT neurons in the vestibular eye movement neuronal pathway to maintain vestibular balance was conjectured to be as follows. PMT neurons transmit vestibular information from the anterior semicircular canals to the cerebellum, forming a cerebellum/brainstem feedback loop. Vestibular information from that loop is integrated in the cerebellum, inhibiting only the anterior semicircular canal neuronal pathway via the flocculus and controlling vestibular balance.