Accession Number : AD0467975

Title :   THE OCULO-GYRAL ILLUSION: A FORM OF APPARENT MOTION WHICH MAY BE OBSERVED FOLLOWING STIMULATION OF THE SEMICIRCULAR CANALS.

Descriptive Note : Research rept.,

Corporate Author : NAVAL SCHOOL OF AVIATION MEDICINE PENSACOLA FLA

Personal Author(s) : Graybiel,Ashton ; Hupp,Dorothy

Report Date : 01 NOV 1945

Pagination or Media Count : 26

Abstract : A number of different physiological and psychological mechanisms may form the basis for the visual appreciation of movement. Thus, the perception of movement may be true or false and may be associated with a moving or relatively motionless eye. We have studied one form of false perception of movement termed the oculogyral illusion, which is due, in large part at least, to nystagmus. The nystagmus has been reflexly produced through stimulation of the receptor mechanism in the semicircular canals as a result of angular acceleration of the body. Two fundamentally different ocular mechanisms are involved depending on whether a real object or an afterimage is in the field of vision. In the former instance the apparent motion is due to the tracking of the image over the retina. In the case of afterimages in illusory motion cannot be due to any modification of the retinal image and may be due to proprioceptive impulses from the extraocular muscles. This method of producing illusory movement offers a simple means of studying the sensitivity of the sensory receptors in the semicircular canals, the reflexly produced nystagmus, and associated phenomena. Measurements can be made, without discomfort to the subject, both during and after rotation. There is much to be learned regarding thresholds of stimulation and factors which might affect it. (Author)

Descriptors :   (*SEMICIRCULAR CANALS, POSITIONING REACTIONS), ROTATION, STIMULATION(PHYSIOLOGY), VESTIBULAR APPARATUS, PERCEPTION, MOTION, VISUAL PERCEPTION, ILLUSIONS, VERTIGO, ADAPTATION(PHYSIOLOGY), AVIATION MEDICINE

Distribution Statement : APPROVED FOR PUBLIC RELEASE