Showing papers in "Vision Research in 1990"

TL;DR: Measurements of contrast sensitivity were obtained from isolated neurons in the lateral geniculate nucleus, striate cortex, and middle temporal visual area of macaque monkeys and show that many neuron in the middle temporal area are more sensitive than any cell encountered in early stages.

TL;DR: The results show that the filter characteristics of striate cortical cells are not necessarily fixed, but can be dynamic, changing according to context, and this study modeled a neuronal ensemble encoding orientation.

TL;DR: Saccadic control signals accurately reflect the properties of three-dimensional rotations, as predicted by a new quaternion model of the saccadic system; models that approximate rotational kinematics using vectorial addition and integration do not predict these findings.

TL;DR: It is suggested that ganglion cell density can fully account for the cortical magnification factor and there is no need to postulate a selective amplification of the foveal representation.

TL;DR: It is shown that unpaired points in binocular images can lead to the formation of subjective occluding contours and surface having the qualitatively appropriate sign of depth, and that the visual system could not recover depth of unpaired Points camouflaged from the other eye against silhouettes.

TL;DR: This paper presents algorithms for computing eye position quaternions and eye angular velocity from two search coils, and shows how differentiation of eye position signals yields poor estimates of all three components of eye velocity.

TL;DR: One implication of these results is that, although the eye has substantial chromatic aberration, the pupil is positioned so as to minimize the transverse component of the aberration for central vision, thereby optimizing foveal image quality for polychromatic objects.

TL;DR: Physiological effects, formerly attributed to a role of calcium as an excitational messenger are shown to be consistent with a biochemical model in which Ca2+ serves as the cytoplasmic signal in a powerful feedback loop that acts to restore the concentration of cGMP both during and after exposure to light.

TL;DR: A significant reduction in contrast sensitivity of the older age group is demonstrated at all but the lowest combinations of spatial and temporal frequencies investigated.

TL;DR: The results indicate straylight to increase with the 4th power of age, doubling at 70.

TL;DR: The morphological and spectral characteristics of purified populations of melanosomes and lipofuscin granules from the human retinal pigment epithelium (RPE) were studied to support the concept that melanogenesis is occurring within the human RPE throughout life and that pigment granules within the RPE undergo age-related modifications during life.

TL;DR: The concept of “Gaussian curvature” of surfaces is employed to derive a class of physiologically plausible operators for the detection of two-dimensional signal variations and it is shown that such an unambiguous detection of ZD-signal properties necessarily employs “and” operations.

TL;DR: It is argued that illusions illustrate powerful constraints upon visual processing: they arise when subjects are instructed to carry out a task to which the visual system is not adapted.

TL;DR: There appeared to be two phases in the development of contrast sensitivity and acuity: between 4 and 9 weeks overall contrast sensitivity increased by a factor of 4-5 at all spatial frequencies, while sensitivity increased systematically at higher spatial frequencies.

TL;DR: Using single color terms of their choice, nine subjects named each of 424 colors twice under carefully-controlled conditions to support the conception that basic color terms refer to fundamental sensations for which there is a specific physiological basis.

TL;DR: This finding suggests that a cell which appears to be dominated by one eye, when monocular tests are conducted, may respond equally under binocular conditions, and proposes an alternative to the conventional notion of a neural mechanism for the processing of information concerning different depths in space.

TL;DR: Long-wavelength visual pigment polymorphism was found in the guppy using microspectrophotometry (MSP), similar to that found in primates, but unlike primates this variation is not sex-linked and may be based on only two visual pigments.

TL;DR: This finding shows that the more precise monocular signals are actively suppressed in fused or partially-fused stereoscopic images.

TL;DR: The neural mechanisms which compute two-dimensional image motion do not strictly implement the intersection-of-constraints construction proposed by Adelson and Movshon (1982), which means that type II patterns have a perceived bias toward the direction of their components, whereas type I patterns have no bias.

TL;DR: Since explicit eye-of-origin information is lost relatively early in the hierarchical organization of cortical visual processing, it is argued that occlusion-related constraints must be embodied at such early levels.

TL;DR: The overall insensitivity of infants to contrast is likely to provide a satisfactory explanation of the poor color vision of infants.

TL;DR: The hypothesis that perception is the computation of a representation that enables us to make reliable and versatile inferences about associations occurring in the world around us is proposed, which implies that the representative elements should be statistically independent in the normal environment.

TL;DR: It is found that when the gratings within the plaid are of different contrast, the perceived direction is not predicted by the intersection of constraints rule, and a revised model, which incorporates a contrast-dependent weighting of perceived grating speed as observed for 1-D patterns, can quantitatively predict most of the results.

TL;DR: This work uses colour matches to demonstrate that departures from "colour constancy" are large and that it is possible to obtain the same colour shifts when the complex Mondrian pattern is replaced by a homogeneous grey field surrounding a test patch.

TL;DR: The shift from assimilation to contrast, as the cinematogram's strips increase in size, suggests that facilitatory and inhibitory influences of the network extend over different distances.

TL;DR: Electrophysiological studies of motion processing in the tectofugal and accessory optic systems are reviewed, and it is suggested these are specialized respectively for the analysis of object motion and self motion.

TL;DR: Rat is the first species for which two different action spectra of photochemical damage have been established, and in similar experimental conditions susceptibility to photic injury in rat is comparable to that in primates.

TL;DR: The results suggest that the optical design of the human eye is optimized to reduce the wavelength dependent phase shift in the optical transfer function, which could be produced by optical TCA.

TL;DR: A lower-field myopia is reported in other species of birds that have a wide range of heights that permits pigeons to keep the ground in focus while they forage, and simultaneously, to monitor the horizon and sky for predators.

TL;DR: Results indicate that the activity of transient channels is attenuated by red relative to white or green backgrounds, which may correspond to the suppressive effects of diffuse red light on neural activity in the transient M pathway of monkey.