Optic organ and cervical proprioceptors in maintenance of body equilibrium.

Two experiments were made on the functional correlation between the optic organ and the cervical proprioceptors in maintenance of body equilibrium. Experiment I: The effects of weak and strong electric stimulation of the deep nuchal muscles on changes in optokinetic nystagmus and optokinetic after-nystagmus were examined in adult non-albino rabbits with binocular vision. Experiment II: Experiment I was repeated on rabbits with monocular vision giving optokinetic stimulation moving from the side of the blindfolded eye to that of the open eye and applying only weak electric stimulation to the neck muscles. The results obtained were as follows: (1) Experiment I: Weak electric stimulation of the deep nuchal muscles of rabbits with binocular vision tended to promote optokinetic nystagmus with either no significant change or decrease in optokinetic after-nystagmus. Strong electric stimulation had the opposite effects, i.e., it tended to inhibit optokinetic nystagmus and activate optokinetic after-nystagmus. It also produced abnormal optokinetic nystagmus, such as the inversion phenomenon of optokinetic nystagmus and "optokinetic nystagmus firing". (2) Experiment II: Weak electric stimulation of the deep nuchal muscles of rabbits with monocular vision had similar effects to those in experiment I, but promotion of optokinetic nystagmus was less obvious, while activation of optokinetic after-nystagmus was more marked. In addition, the inversion phenomenon of optokinetic nystagmus developed even on weak electric stimulation. From these results the following conclusions were drawn: (1) The cervical proprioceptors can function in two mechanisms causing promotion and break down of equilibrium of the optokinetic system. (2) The cervical proprioceptors, as an organ of equilibrium, can exert two different actions on the optokinetic eye reflexes, i.e., they can promote optokinetic nystagmus and inhibit optokinetic after-nystagmus.

Studies on ataxia of lumbar origin in cases of vertigo due to whiplash injury.

We draw the following conclusions from clinical observations on traumatized patients with vertigo and lumbar pain. 1) Hypertonicity of the lumbar soft supporting tissues, and especially the lumbar erector muscles (i.e., over-excitment of the lumbar proprioceptors) is a cause of vertigo due to whiplash injury. Equilibrium tests after fixing the waist with a corset are useful for detecting ataxia of lumbar origin. 2) Over-excitement of the lumbar porpiroceptors and dysfunction of the brain stem and the cerebellum are closely related in bringing about vertigo due to whiplash injury. The lumbar proprioceptors in particular may be important, in close correlation with the cerebellum in producing vertigo of this type. 3) Infiltration of procaine into tender spots in the lumbar soft supporting tissues is helpful in therapy of disequilibrium of the eyes and body and of cerebellar ataxia.