On the Changes of Nystagmus Caused by Ultrasound-Produced Focal Lesions in the Brain-Stem

Abstract

Results obtained are summarized as follows: (1) The presence of both the medial longitudinal fasciculus and ponto-mesencephalic reticular formation is of vital importance in the evocation of normal nystagmic reactions. (2) The ponto-mesencephalic reticular formation has the nystagmic controlling mechanism which produces a phasic rhythmic neural activity, especially the reticular formation on the level of nucleus motorius nervi trigemini plays an important role for the occurrence of vestibular nystagmus. The author infers that a nystagmic eliciting centre is located in it. (3) Optokinetic fibre tracts have no direct innervation with vestibular tracts in the brain-stem. (4) The destruction of the reticular formation just below the nucleus trochlearis causes the optokinetic inversion.