Elimination of the color discrimination impairment along the blue-yellow axis in patients with hypothyroidism after treatment with levothyroxine as assessed by the Farnsworth-Munsell 100 hue test.

Our previous study has shown that individuals with untreated hypothyroidism display significantly higher partial error scores ( ) along the blue-yellow axis compared to the red-green axis than normal individuals using the Farnsworth-Munsell 100 hue test [J. Opt. Soc.

Visual noise effect on reading in three developmental disorders: ASD, ADHD, and DD.

Background And Aims: Developmental disorders such as Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder (ADHD), and Developmental Dyslexia (DD) are reported to have more visual problems, oral language difficulties, and diminished reading skills in addition to their different diagnostic features. Moreover, these conditions also have increased internal noise and probably an impaired ability of external noise filtering. The aim of the present study was to compare the reading performance of these groups in the presence of external visual noise which disrupts the automatic reading processes through the degradation of letters.

How the External Visual Noise Affects Motion Direction Discrimination in Autism Spectrum Disorder.

Along with social, cognitive, and behavior deficiencies, peculiarities in sensory processing, including an atypical global motion processing, have been reported in Autism Spectrum Disorder (ASD). The question about the enhanced motion pooling in ASD is still debatable. The aim of the present study was to compare global motion integration in ASD using a low-density display and the equivalent noise (EN) approach.

Visual Noise Effect on Contour Integration and Gaze Allocation in Autism Spectrum Disorder.

Contradictory results have been obtained in the studies that compare contour integration abilities in Autism Spectrum Disorders (ASDs) and typically developing individuals. The present study aimed to explore the limiting factors of contour integration ability in ASD and verify the role of the external visual noise by a combination of psychophysical and eye-tracking approaches. To this aim, 24 children and adolescents with ASD and 32 age-matched participants with typical development had to detect the presence of contour embedded among similar Gabor elements in a Yes/No procedure.

Color discrimination assessment in patients with hypothyroidism using the Farnsworth-Munsell 100 hue test.

There is evidence in the literature that hypofunction of the thyroid gland (hypothyroidism) affects color vision in rodents by influencing the production of the visual pigment opsin. The effect of hypothyroidism on color vision in humans has not been examined in any great detail. In this cross-sectional study we evaluated color discrimination using the Farnsworth-Munsell 100 hue test (FM-100 test) in 25 individuals with pre-treatment hypothyroidism (mean age ${38}\;{\pm }\;{9}.

Contextual modulation induced by contrast and speed on direction perception.

We examined the direction perception in centre-surround multielement configurations with varying contrast and velocity to better understand the consequences of surround interactions of orientation and motion direction perception. The stimuli consisted of Gabor elements moving either parallel or orthogonal to their orientation with two different speeds. The surround motion direction varied from 0° to 315° with a step of 45°.

Spike Timing Neural Model of Motion Perception and Decision Making.

The paper presents a hierarchical spike timing neural network model developed in NEST simulator aimed to reproduce human decision making in simplified simulated visual navigation tasks. It includes multiple layers starting from retina photoreceptors and retinal ganglion cells (RGC) via thalamic relay including lateral geniculate nucleus (LGN), thalamic reticular nucleus (TRN), and interneurons (IN) mediating connections to the higher brain areas-visual cortex (V1), middle temporal (MT), and medial superior temporal (MTS) areas, involved in dorsal pathway processing of spatial and dynamic visual information. The last layer-lateral intraparietal cortex (LIP)-is responsible for decision making and organization of the subsequent motor response (saccade generation).

Global orientation estimation in noisy conditions.

The present paper studies the perceived orientation of line patterns with variable elongation, line length, orientation jitter, and presentation time. It evaluates whether the internal noise and sampling efficiency evaluated by equivalent noise paradigm (Pelli 1981) depend on the spatial configuration and temporal characteristics of the stimulation. The evaluated internal noise was compared to the results of double-pass noise estimation.

Age-related changes in fine motion direction discriminations.

The present study used an equivalent noise method to characterize the sources of reduced performance in fine discrimination of motion with age. We varied the density of the displays, the speed and speed variability and the temporal correlation of dots' motion in successive frames to assess their effect on the sensitivity to motion direction. The results showed that, in all experimental conditions, the older observers had higher levels of internal noise.

Age-related changes in sensitivity to global speed.

We examined the effect of speed magnitude and range on the sensitivity to global speed in two different age groups. Stimuli consisted of band-pass dots whose speeds were perturbed by time-correlated or -uncorrelated random noise. The observer discriminated which of two sequentially presented stimuli moved faster.

Effect of planar cuts' orientation on the perceived surface layout and object's shape.

The effect of the orientation of the cutting planes producing planar curves over the surface of an object on its perceived pose and shape was investigated for line drawings representing three-dimensional objects. The results suggest that the orientational flow produced by the surface curves introduces an apparent object rotation in depth and in the image plane and changes in its perceived elongation. The apparent location of the nearest points is determined by the points of maximal view-dependent unsigned curvature of the surface curves.

Effects of surface markings on judgments of motion direction.

The effects of surface markings on perceived motion direction were examined for a rotating sphere in a structure-from-motion display. The markings were dot patterns representing separate line segments or intersecting line segments (crosses) covering the surface of the sphere. The orientation of the surface markings and their intersection angles affected the perceived direction of motion, suggesting that the markings were not interpreted as geodesics or planar cuts on the surface.

Detection of motion discontinuities between complex motions.

Three main experiments were performed to evaluate the ability of human observers to detect non-homogeneity in a motion field caused by the presence of two adjacent complex motions, having a common motion component. The detection performance varied significantly depending on the common motion component in the motion field. The highest detection rate was observed when the common motion component was radial or rotational flow.

Visual interpolation of surfaces defined through motion.

The ability of human visual system to interpolate surfaces when the structure of the objects was defined through motion was investigated in a series of experiments. The type of the surface, the position of an area devoid of dots (the gap) and the type of gap edges was varied. The local orientation of the interpolated surfaces was estimated by a method of adjustment.