While it is generally accepted that foveal visual acuity in the adult has reached an optimal value, claims for improvement of peripheral acuity with training in the adult persist in the literature. Practice effects in peripheral hyperacuity have been amply documented. A carefully controlled test is here reported to examine the influence of training on the resolution thresholds for two lines and...

Comparison of the spatiotemporal information delivered by ganglion cells with human psychophysical performance may give insight to how retinal information is utilized by cortical mechanisms, and constrain models of spatiotemporal processing. Ganglion cells' responses were measured with drifting gratings of various spatial and temporal frequencies and contrasts. The spatiotemporal precision of c...

B. Synthetic procedures S2 B1. Synthesis of known compounds S2 B2. Synthesis of novel compounds S2 Fully deprotected Ni pyridyl porphyrin dimer NiP2 S2 Phenylacetylene Zn porphyrin tetramer PhC2-ZnP4 S3 Phenylacetylene Ni porphyrin tetramer PhC2-NiP4 S4 Phenylacetylene Ni porphyrin hexamer PhC2-NiP6 S5 Fully THS protected Zn porphyrin heptamer THS-ZnP7, octamer THS-ZnP8 and dodecamer THS-ZnP12 ...

Humans resolve the spatial alignment between two visual stimuli at a resolution that is substantially finer than the spacing between the foveal cones. In this paper, we analyze the factors that limit the information at the cone photoreceptors that is available to make these acuity judgments (Vernier acuity). We use open-source software, ISETBIO to quantify the stimulus and encoding stages in th...

In perceptual learning, performance usually improves when observers train with one type of stimulus, for example, a bisection stimulus. Roving denotes the situation when, instead of one, two or more types of stimuli are presented randomly interleaved, for example, a bisection stimulus and a vernier. For some combinations of stimulus types, performance improves in roving situations whereas for o...

Location-specific perceptual learning can be rendered transferrable to a new location with double training, in which feature training (e.g., contrast) is accompanied by additional location training at the new location even with an irrelevant task (e.g. orientation). Here we investigated the impact of relevancy (to feature training) and demand of location training tasks on double training enable...

The objective of this study was to measure the maximum superior and inferior lengths of the suprascapular notch with the help of a Vernier caliper and to classify the notches accordingly into four types. This is an observational study, conducted from January to December 2009 at Islamic International Medical College, Rawalpindi. Two hundred and fifty dried human scapulae were procured and measur...

The present study tests the effects of practice on parafoveal vernier and resolution acuity. By measuring task specificity, transfer of training to other retinal locations in the trained eye and transfer of training to the untrained eye, we directly address whether improvement on these tasks is the result of changes in the underlying physiological processes or simply the development of new cogn...

We examined a visual search task, in which observers responded to the high-acuity aspect of a pop-out target (shape of an odd-colored diamond or vernier offset of an odd spatial-frequency patch). Repetition of the attention-driving feature (color or spatial frequency) in this task primes the pop-out; repetition of the high-acuity aspect (shape, vernier offset) does not. Priming of pop-out is du...

The responses of 20 young adult emmetropes with normal color vision were measured on a battery of visual performance tasks. Using previously documented tests of known reliability, we evaluated orientation discrimination, contrast sensitivity, wavelength sensitivity, vernier acuity, direction-of-motion detection, velocity discrimination, and complex form identification. Performance varied marked...