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Scotopic visibility curve in man, obtained by the visual evoked response
1200
IUPS-ISCERG
Symposium Papers
X-ray diffraction patterns from all parts of the eye show that the rods orient tobvards the light. It would seem inefficient to specify genetically the unique orientation found at each point on the retina-I conjecture that it is the light which orients the membranes, if not in the adult then at least during the growth of the embryonic outer segment. This conjecture will be refuted if no change is found in the arcing of the X-ray pattern when frogs are grown in the dark.
20 Scotopic visibility curve in man, obhhed
by the visual evoked respoae
C. HUBER and EWKO ADACHI-USAMI. schaft, 635 Bad Nauheim, Germany
W. G. Kerckhofilnstitut
der Max-Planck-Gesell-
THE SPECTRALsensitivity of the visual evoked response has been repeatedly shown to follow the photopic spectral sensitivity curve. Under scotopic conditions the VER differs markedly from that under photopic conditions (smaller amplitudes, latencies of about 200 msec). Using latency as the criterion the energy needed for a constant VER after dark adaptation is measured between 398 and 591 nm. At test light luminances ranging from 1 to 2 log units above the sensory threshold the VER curve follows the scotopic CIE sensitivity curve. The test light is a 10” circular spot centrally projected in Maxwellian view. The subject is darkadapted for 20 min and the responses to 256 flashes of 100 msec duration are averaged at a rate of Z/set. If the test light is projected to a rod-rich region (20” temporally to the visual axis) the evoked response is minimal or even absent. The specificity of the VER appears therefore to be linked primarily to the location of the stimulus and not to the photopic or scotopic system.
21
NATHANW. PERRY, JR. Visual Sciences Laboratory, University of Florida, Gainsvilk, Fla. 32601, U.S.A.
MOST theories of binocular fused vision require a weighted constant to account for any unequal contributions to the given perception due to unequal dominance of the eyes. However, most data used by fusion theories has been obtained during dichopticviewing with rivalry. The series of experiments to be reported were done to determine the contribution of each eye when dissimilar information was fused in normal binocular vision. It was assumed that contribution of pattern information from the amblyopic eye to the fused perception would be negligible in amblyopic subjects. Contributions from each eye in binocular vision were measured electrophysiologically and behaviorally. Letters, numbers and random patterns were presented sequentially in all monocular, binocular and dichoptic combinations. An electrophysiological measure of the contribution of each eye to the perception was the visual evoked response (VER) which was recorded from four scalp areas. A behavioral measure was recorded simultaneously in the form of
IUPS-ISCERG
Symposium Papers
X-ray diffraction patterns from all parts of the eye show that the rods orient tobvards the light. It would seem inefficient to specify genetically the unique orientation found at each point on the retina-I conjecture that it is the light which orients the membranes, if not in the adult then at least during the growth of the embryonic outer segment. This conjecture will be refuted if no change is found in the arcing of the X-ray pattern when frogs are grown in the dark.
20 Scotopic visibility curve in man, obhhed
by the visual evoked respoae
C. HUBER and EWKO ADACHI-USAMI. schaft, 635 Bad Nauheim, Germany
W. G. Kerckhofilnstitut
der Max-Planck-Gesell-
THE SPECTRALsensitivity of the visual evoked response has been repeatedly shown to follow the photopic spectral sensitivity curve. Under scotopic conditions the VER differs markedly from that under photopic conditions (smaller amplitudes, latencies of about 200 msec). Using latency as the criterion the energy needed for a constant VER after dark adaptation is measured between 398 and 591 nm. At test light luminances ranging from 1 to 2 log units above the sensory threshold the VER curve follows the scotopic CIE sensitivity curve. The test light is a 10” circular spot centrally projected in Maxwellian view. The subject is darkadapted for 20 min and the responses to 256 flashes of 100 msec duration are averaged at a rate of Z/set. If the test light is projected to a rod-rich region (20” temporally to the visual axis) the evoked response is minimal or even absent. The specificity of the VER appears therefore to be linked primarily to the location of the stimulus and not to the photopic or scotopic system.
21
NATHANW. PERRY, JR. Visual Sciences Laboratory, University of Florida, Gainsvilk, Fla. 32601, U.S.A.
MOST theories of binocular fused vision require a weighted constant to account for any unequal contributions to the given perception due to unequal dominance of the eyes. However, most data used by fusion theories has been obtained during dichopticviewing with rivalry. The series of experiments to be reported were done to determine the contribution of each eye when dissimilar information was fused in normal binocular vision. It was assumed that contribution of pattern information from the amblyopic eye to the fused perception would be negligible in amblyopic subjects. Contributions from each eye in binocular vision were measured electrophysiologically and behaviorally. Letters, numbers and random patterns were presented sequentially in all monocular, binocular and dichoptic combinations. An electrophysiological measure of the contribution of each eye to the perception was the visual evoked response (VER) which was recorded from four scalp areas. A behavioral measure was recorded simultaneously in the form of