XL Experimental Studies on Vestibular Mechanisms

Publisher Website
Google Scholar
Abstract
Cortical ablations (hemidecortication and temporal lobe) and artificial tumor implants were performed on cats in order to study the effects of these lesions upon the central oculo-vestibular system. Electronystagmorgraphic recordings of induced optokinetic, caloric, and rotatory nystagmus were made pre-operatively and at one week and five to six week postoperative intervals. Analysis of these records revealed that the ablative lesions resulted in a directional preponderance of induced nystagmus toward the side of the lesion. The results of the cats with artificial tumor implants showed variability in their test results. Directional preponderance of induced nystagmus in this group of cats was toward the side of the tumor in two, to the opposite side in one, and two cats had no significant preponderance. The variability in the results was attributed to the size, location and degree of pressure exerted on the cortex and underlying oculo-vestibular pathways. The results of these experiments were utilized in the formulating an explanation of the numerous controversial clinical reports on directional preponderance of induced nystagmus in brain tumors.