Accession Number : AD0624790

Title :   CORTICAL CONTROL OF EYE MOVEMENTS AND VISUAL THRESHOLD.

Descriptive Note : Final rept., 1 Jun 64-1 Jun 65,

Corporate Author : INSTITUTE FOR PERCEPTION RVO-TNO SOESTERBERG (NETHERLANDS)

Personal Author(s) : Bouman,Maarten A.

Report Date : OCT 1965

Pagination or Media Count : 45

Abstract : Experimental investigations were conducted on the increase in the threshold for visual perception which occurs just prior to, and during eye movements. To measure the visual threshold in the vicinity of eye movement an apparatus was constructed having alternately burning lights. Some time after switching, a flash of short duration of controlled intensity was presented which fell in the vicinity of the subject's eye movement. Eye movements were measured by reflection of light from the surface of the eye. The reflection data is fed to a 'pattern recognizer' which records the onset of eye movement. The subject records whether or not he saw the flash. The threshold for perception as a function of eye movement was measured. The equipment could present one or two light flashes to the subject. Each light source had a diameter of 7 minutes of arc, with an angular separation between the two lights up to several degrees. It was found that the detection of one light flash would facilitate the detection of the other light flash. For example, if the probability of detecting either light, separately, was 0.3, the probability of detecting both together was 0.2, rather than 0.09. This facilitation experiment was then repeated with a resting eye, with the following results, which hold for both the light adapted and the dark adapted eye: 1. It is most likely a retinal effect, which affects both rods and cones equally. 2. Outside the area of summation the distance between the two flashes is of minor importance. (Author)

Descriptors :   (*VISUAL PERCEPTION, THRESHOLDS(PHYSIOLOGY)), CEREBRAL CORTEX, EYE, MOTION, VISION, NERVOUS SYSTEM, PHYSIOLOGY, LIGHT, INTENSITY, RETINA, ADAPTATION(PHYSIOLOGY), ELECTROENCEPHALOGRAPHY, PROBABILITY, NETHERLANDS

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE