Sensory systems continuously mold themselves to the widely varying contexts in which they must operate. Studies of these adaptations have played a long and central role vision science. In part this is because specific remain powerful tool for dissecting vision, by exposing mechanisms that are adapting. That is, "if it adapts, it's there." Many insights about come from using adaptation way, as method. A second important trend has been realization processes essential how works, thus likely...

If striate cells had the receptive-field (RF) shapes classically attributed to them, their preferred spatial frequencies would vary considerably with orientation. Other models of RF shape predict a greater independence between orientation and spatial-frequency tuning. We have examined this by recording responses cat striate-cortex wide range different combinations. In almost all studied, peak did not consistently frequency, but majority showed some change in tuning The amount frequency...

We examined individual differences in the color appearance of nonspectral lights and asked how they might be related to sensitivity chromatic stimuli. Observers set unique hues for moderately saturated equiluminant stimuli by varying their hue angle within a plane defined LvsM SvsLM cone-opponent axes that are thought characterize early postreceptoral coding. Unique red settings were close +L pole axis, while green, blue, yellow clustered along directions intermediate thus corresponded...

We have examined the accuracy of orientation and spatial-frequency discrimination for sine-wave gratings that vary in either luminance or color. The equiluminant chromatic were modulated along a tritanopic confusion axis (so they detectable on basis activity only short-wavelength-sensitive cones) an constant cone excitation could be detected opposing long- medium-wavelength-sensitive cones). Grating contrasts ranged from detection threshold to highest levels we produce; color patterns...

Images with excessive energy at medium spatial frequencies (Fernandez and Wilkins, 2008 Perception37 1098–1113), or that have high color contrast little no luminance (Wilkins et al, Supplement, 144–145) appear uncomfortable aversive can induce headaches in hypersensitive observers. Such stimuli are uncharacteristic of natural images, we examined whether visual discomfort more generally increases deviations from the chromatic properties scenes. Observers rated level artistic merit images...

We have used a factor analysis of the Stiles–Burch [ Opt. Acta6, 1 ( 1959)] 10° field color matches to examine basis individual differences in made by observers with normal vision. The are primarily due interobserver variations macular-pigment density [with standard deviation (σ) 0.12 at 460 nm]; lens-pigment (σ = 0.18 400 nm); spectral position long-wavelength-sensitive 50.3 cm−1), medium-wavelength sensitive 31.9 and short-wavelength-sensitive 45.3 cm−1) photopigments; covarying densities...

The optical density of the human crystalline lens progressively increases with age, greatest increase in visible spectrum being at short wavelengths. This produces a gradual shift spectral distribution light reaching retina, yet color appearance remains relatively stable across life span, implying that visual system adapts to compensate for changes sensitivity. We explored properties this adaptive renormalization by measuring following cataract surgery. When is removed, patients often report...

Information about colour is initially extracted by the visual system in terms of activity within a small number receptor types with different spectral sensitivities, and then recoded channels that respond to combinations signals. Many insights have been gained these post-receptoral transformations, yet their nature remain poorly defined. This review examines how signals coding are organized human system, affected processes adaptation. Sensitivity controlled two distinct classes adaptation...

Adapting to blurred or sharpened images alters the perceived focus of subsequently viewed images. We examined whether these adaptation effects could arise from actual sphero-cylindrical refractive errors, by testing aftereffects in simulating second-order astigmatism. Image blur was varied negative (vertical) through isotropic positive (horizontal) astigmatism while maintaining constant strength. A 2AFC staircase used estimate stimulus that appeared isotropically before after adapting with...

Sensory systems constantly adapt their responses to match the current environment. These adjustments occur at many levels of system and increasingly appear calibrate even for highly abstract perceptual representations stimulus. The similar effects adaptation across very different stimulus domains point common design principles but also continue raise questions about purpose adaptation.

Background The image formed by the eye's optics is inherently blurred aberrations specific to an individual's eyes. We examined how visual coding adapted optical quality of eye. Methods and Findings assessed relationship between perceived blur retinal resulting from high order in optics. Observers judged perceptual a psychophysical two-alternative forced choice paradigm, on stimuli viewed through perfectly corrected (using deformable mirror compensate for aberrations). Realistic different...

Spaceflight Associated Neuro-Ocular Syndrome (SANS) refers to a unique collection of neuro-ophthalmic clinical and imaging findings that are observed in astronauts during long duration spaceflight. These include optic disc edema, posterior globe flattening, retinal nerve layer fiber thickening, sheath distension, hyperopic shift. SANS currently serves as large barrier deep space exploration; however, the exact pathophysiology is still being investigated. While in-flight exists on...