Showing papers in "Vision Research in 1999"

TL;DR: A new Bayesian adaptive method for acquisition of both threshold and slope of the psychometric function that updates posterior probabilities in the two-dimensional parameter space of psychometric functions and makes predictions based on the expected mean threshold and slopes.

TL;DR: Experiments were conducted to study if electrical stimulation of the retinal surface can elicit visual sensation in individuals blind from end-stage retinitis pigmentosa (RP) or age-related macular degeneration (AMD).

TL;DR: A series of chronic behavioral experiments show that modest levels of electrical currents passed into cortex via this array can evoke sensory percepts, and high count arrays of penetrating microelectrodes similar to this design could provide a useful tool for studies of the psychophysics of phosphene perception in human volunteers.

TL;DR: The studies reinforce the conclusion that lens hardening must be considered as an important factor in the development of presbyopia, that age changes in the human lens are not limited to the loss of accommodation that characterizes Presbyopia but that the lens optical and physical properties change substantially with age in a complex manner.

TL;DR: The pooled activity of large numbers of neurons can reasonably well predict behavioral performance and the data suggest that contrast gain in early visual cortex depends systematically on spatial frequency.

TL;DR: Evidence is found that two independent mechanisms, external noise exclusion and stimulus enhancement support perceptual learning across a range of tasks and it is suggested that both mechanisms may reflect re-weighting of stable early sensory representations.

TL;DR: The main finding was that spectacle lenses could predictably alter the growth of one or both eyes resulting in appropriate compensating refractive changes in both the hyperopic and myopic directions.

TL;DR: It is concluded that observers' cue-combination strategies are indeed optimal, at least under the conditions studied here, and the predictions of the optimal models closely match the experimental data.

TL;DR: The model predicts that using optimum spatiotemporal summation the locust can extend its vision to light intensities more than 100,000 times dimmer than if it relied on its optics alone.

TL;DR: The authors used precueing to explore the effect of covert transient attention on performance in spatial resolution tasks and found that the performance improvement at attended locations results from an enhanced spatial resolution at the cued location, not just from distractor exclusion, diminished uncertainty, or decisional factors.

TL;DR: The results suggest that the recognition of facial images is tuned to a relatively narrow band (< 2 octaves) of mid object spatial frequencies.

TL;DR: During human aging there is a dramatic slowing in rod-mediated dark adaptation that can be attributed to delayed rhodopsin regeneration, which may contribute to night vision problems commonly experienced by the elderly.

TL;DR: Results basically support the concept of replacing damaged photoreceptors with subretinally implanted stimulation devices and show no significant side effect of subretinal implants on retinal function or the architecture of the inner retina.

TL;DR: The view that the execution of saccades requires focal as opposed to distributed attention is supported and that this focal attention is guided by a short term memory system which facilitates the rapid refixation of gaze to recently foveated targets is supported.

TL;DR: Surprisingly, face identification was impossible for human observers at all center frequencies except 8.8 and 17.5 c/object, so the failure to identify faces reflects constraints on visual processing rather than a lack of stimulus information.

TL;DR: A simple model for predicting ease of search for a unique motion, based upon a quantitative measure of target saliency, predicts a number of well-known motion search phenomena and suggests that one control for target Saliency as well as target discriminability when drawing conclusions about visual system mechanisms from search experiments.

TL;DR: Two methods are used to estimate short-wave (S) cone spectral sensitivity and propose new S-cone spectral sensitivity functions, which are consistent with the color matching data of Stiles and Burch, and other psychophysically measured functions, such as pi 3.

TL;DR: The results suggest that temporal vision matures more rapidly than spatial vision during childhood, and is likely mediated by different underlying neural mechanisms that mature at different rates.

TL;DR: It is shown that the neural response properties at the system level should be adjusted to the changing statistics of the input so as to maximize information transmission, and that this principle accounts for several well-documented psychophysical phenomena, including the tilt aftereffect.

TL;DR: An oriented DOG (ODOG) model is introduced which differs from the DOG model in that the filters are anisotropic and their outputs are pooled nonlinearly and argues strongly that the induced brightness phenomena of SBC, GI, the White effect and the Todorovic demonstration, primarily reflect early-stage cortical filtering operations in the visual system.

TL;DR: It is shown that a simple race model with a linear rise to threshold may underlie behavioural performance in tasks of this kind, and this model correctly predicted the probability of successful saccade inhibition as a function of the stop-signal delay.

TL;DR: It is found that VSR and sensed eye position are both used to interpret the measured horizontal disparities and the weights varied across viewing conditions because the informativeness of the signals they employ vary from one situation to another.

TL;DR: The hypothesis that regulation of the time-dependent mechanical properties of fibrous mammalian sclera plays a role in controlling axial elongation rate during both normal emmetropization and the development of refractive errors is supported.

TL;DR: To characterize the visual physiology of the wild type (C57BL/6J) mouse, Visual Evoked Potentials (VEPs) are recorded from the primary visual cortex to provide a comprehensive framework for characterizing visual phenotypes of a variety of transgenic mice.

TL;DR: The spatial characteristics of attention were studied by measuring the accuracy with which two target letters could be identified from a circular display of 24 characters: performance was poorest when the targets were close together and improved with increasing target separation.

TL;DR: The independent covariance of eye movements during different visual tasks shows that saccadic eye movementsDuring active tasks like reading or visual search differ from those engaged during the passive inspection of visual scenes, which reveals an endogenous influence on oculomotor control.

TL;DR: Objective and subjective measurements of DOF are only slightly affected by pupil size, wavelength and spectral composition, which allows us to evaluate the role of ocular aberrations and Stiles-Crawford effect.

TL;DR: It is shown that a newer version of E-Z Reader which still assumes that lexical access is the engine driving eye movements also predicts the locations of fixations and within-word refixations, and therefore provides a viable framework for understanding how both linguistic and oculomotor variables affect eye movements in reading.

TL;DR: The present investigation assessed the effects of rotation on same-different judgments for matching novel objects and found that NAPs offer a striking advantage over MPs for object classification and are therefore more likely to play a central role in the representation of objects.

TL;DR: Some of the recently characterised behaviours in insects are reviewed, the inferred properties of the underlying movement-detecting processes are described, and modified or new models to account for them are proposed.