scholarly journals Is Peripheral Motion Detection Affected by Myopia?

2021 ◽  
Vol 15 ◽  
Author(s):  
Junhan Wei ◽  
Deying Kong ◽  
Xi Yu ◽  
Lili Wei ◽  
Yue Xiong ◽  
...  
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Motion Detection ◽  
High Speed ◽  
Detection Threshold ◽  
High Spatial Frequency ◽  
Spherical Equivalent ◽  
Detection Thresholds ◽  
Significant Difference ◽  
Motion Speed

PurposeThe current study was to investigate whether myopia affected peripheral motion detection and whether the potential effect interacted with spatial frequency, motion speed, or eccentricity.MethodsSeventeen young adults aged 22–26 years participated in the study. They were six low to medium myopes [spherical equivalent refractions −1.0 to −5.0 D (diopter)], five high myopes (<-5.5 D) and six emmetropes (+0.5 to −0.5 D). All myopes were corrected by self-prepared, habitual soft contact lenses. A four-alternative forced-choice task in which the subject was to determine the location of the phase-shifting Gabor from the four quadrants (superior, inferior, nasal, and temporal) of the visual field, was employed. The experiment was blocked by eccentricity (20° and 27°), spatial frequency (0.6, 1.2, 2.4, and 4.0 cycles per degree (c/d) for 20° eccentricity, and 0.6, 1.2, 2.0, and 3.2 c/d for 27° eccentricity), as well as the motion speed [2 and 6 degree per second (d/s)].ResultsMixed-model analysis of variances showed no significant difference in the thresholds of peripheral motion detection between three refractive groups at either 20° (F[2,14] = 0.145, p = 0.866) or 27° (F[2,14] = 0.475, p = 0.632). At 20°, lower motion detection thresholds were associated with higher myopia (p < 0.05) mostly for low spatial frequency and high-speed targets in the nasal and superior quadrants, and for high spatial frequency and high-speed targets in the temporal quadrant in myopic viewers. Whereas at 27°, no significant correlation was found between the spherical equivalent and the peripheral motion detection threshold under all conditions (all p > 0.1). Spatial frequency, speed, and quadrant of the visual field all showed significant effect on the peripheral motion detection threshold.ConclusionThere was no significant difference between the three refractive groups in peripheral motion detection. However, lower motion detection thresholds were associated with higher myopia, mostly for low spatial frequency targets, at 20° in myopic viewers.

scholarly journals Contrast thresholds reveal different visual masking functions in humans and praying mantises

2017 ◽  
Author(s):  
Ghaith Tarawneh ◽  
Vivek Nityananda ◽  
Ronny Rosner ◽  
Steven Errington ◽  
William Herbert ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Motion Detection ◽  
Visual Masking ◽  
High Spatial Frequency ◽  
Visual Noise ◽  
Frequency Noise ◽  
Detection Systems ◽  
Spatial Frequencies ◽  
Summary Statement ◽  
Contrast Thresholds

AbstractRecently, we showed a novel property of the Hassenstein-Reichardt detector: namely, that insect motion detection can be masked by “invisible” noise, i.e. visual noise presented at spatial frequencies to which the animals do not respond when presented as a signal. While this study compared the effect of noise on human and insect motion perception, it used different ways of quantifying masking in two species. This was because the human studies measured contrast thresholds, which were too time-consuming to acquire in the insect given the large number of stimulus parameters examined. Here, we run longer experiments in which we obtained contrast thresholds at just two signal and two noise frequencies. We examine the increase in threshold produced by noise at either the same frequency as the signal, or a different frequency. We do this in both humans and praying mantises (Sphodromantis lineola), enabling us to compare these species directly in the same paradigm. Our results confirm our earlier finding: whereas in humans, visual noise masks much more effectively when presented at the signal spatial frequency, in insects, noise is roughly equivalently effective whether presented at the same frequency or a lower frequency. In both species, visual noise presented at a higher spatial frequency is a less effective mask.Summary StatementWe here show that despite having similar motion detection systems, insects and humans differ in the effect of low and high spatial frequency noise on their contrast thresholds.

scholarly journals Visual acuity of budgerigars for moving targets

Biology Open ◽  
2021 ◽  
Author(s):  
Sandra Chaib ◽  
Juliane Gaviraghi Mussoi ◽  
Olle Lind ◽  
Almut Kelber
Keyword(s):  
Visual Acuity ◽  
Visual Field ◽  
Spatial Frequency ◽  
Detection Threshold ◽  
Moving Targets ◽  
Resolution Limit ◽  
Food Items ◽  
Visual Spatial ◽  
Behavioural Tests ◽  
Circular Target

For a bird, it is often vital to visually detect food items, predators, or individuals from the same flock, i.e. moving stimuli of various shapes. Yet, behavioural tests of visual spatial acuity traditionally use stationary gratings as stimuli. We have behaviourally tested the ability of budgerigars (Melopsittacus undulatus) to detect a black circular target, moving semi-randomly at 1.69 degrees second−1 against a brighter background. We found a detection threshold of 0.107±0.007 degrees of the visual field for target size corresponding to a resolution of a grating with a spatial frequency of 4.68 cycles degree−1. This detection threshold is lower than the resolution limit for gratings but similar to the threshold for stationary single objects of the same shape. We conclude that the target acuity of budgerigars for moving single targets, just as for stationary single targets, is lower than their acuity for gratings.

The Role of High Spatial Frequencies in Hemispheric Processing of Categorical and Coordinate Spatial Relations

2004 ◽  
Vol 16 (9) ◽  
pp. 1576-1582 ◽  
Author(s):  
Matia Okubo ◽  
Chikashi Michimata
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
Right Hemisphere ◽  
High Spatial Frequency ◽  
Spatial Relation ◽  
Spatial Relations ◽  
Right Visual Field ◽  
Spatial Frequencies ◽  
Low Pass ◽  
Categorical Task

Right-handed participants performed categorical and coordinate spatial relation tasks on stimuli presented either to the left visual field-right hemisphere (LVF-RH) or to the right visual field-left hemisphere (RVF-LH). The stimuli were either unfiltered or low-pass filtered (i.e., devoid of high spatial frequency content). Consistent with previous studies, the unfiltered condition produced a significant RVF-LH advantage for the categorical task and an LVF-RH advantage for the coordinate task. Low-pass filtering eliminated this Task × Visual Field interaction; thus, the RVF-LH advantage disappeared for the categorical task. The present results suggest that processing of high spatial frequency contributes to the left hemispheric advantage for categorical spatial processing.

Accurate Determination of the Cold Detection Threshold with High-Speed Cooling of the Skin

Pain Medicine ◽  
2020 ◽  
Vol 21 (12) ◽  
pp. 3428-3436
Author(s):  
Segolene Lithfous ◽  
Olivier Després ◽  
Thierry Pebayle ◽  
Claudia Casadio ◽  
Andre Dufour
Keyword(s):  
High Speed ◽  
Accurate Determination ◽  
Detection Threshold ◽  
Detection Thresholds ◽  
Temperature Ramp ◽  
Temperature Ramps ◽  
The Subject ◽  
Order Four ◽  
Healthy Participants

Abstract Objective This study used high-speed cooling of the skin and exact control of stimulus duration to measure the cold detection threshold in healthy participants. The objective was to compare the method of limits, in which the temperature is slowly and gradually increased/decreased until the subject perceives the stimulation, and the method of levels, in which the subject must detect brief thermal stimulations close to the threshold of perception. Methods Twenty healthy volunteers (nine women, 11 men) aged 20–30 years participated in the study. The method of limits and method of levels were performed in all subjects in a counterbalanced order. Four cold detection thresholds were measured with the method of levels, with a temperature ramp of 300°C/sec and stimulus durations of 50 ms, 100 ms, 300 ms, and 500 ms. Three thresholds were measured with the method of limits, with temperature ramps of 1°C/sec, 2°C/sec, and 4°C/sec. Results On average, the cold detection thresholds were −0.47°C below skin temperature with the method of levels and −1.67°C the method of limits. Interindividual variability was significantly lower with the method of levels than with the method of limits. Conclusions These results suggest that the method of levels is more accurate than the method of limits for measuring cold detection threshold. The improvement of cold detection threshold measurement may provide new perspectives to more precisely assess the function of A-delta fibers and the spino-thalamic pathway.

Alcohol does not affect visual contrast gain mechanisms

1999 ◽  
Vol 16 (4) ◽  
pp. 675-680 ◽  
Author(s):  
PAULINE PEARSON ◽  
BRIAN TIMNEY
Keyword(s):  
Spatial Frequency ◽  
Detection Threshold ◽  
Discrimination Performance ◽  
Detection Thresholds ◽  
Contrast Gain ◽  
Visual Contrast ◽  
Increment Threshold ◽  
Spatial Frequencies ◽  
Contrast Discrimination ◽  
Induced Changes

It has been suggested that acetylcholine plays a role in contrast discrimination performance and the regulation of visual contrast gain (Smith, 1996). Since alcohol has been shown to reduce levels of acetylcholine and contrast sensitivity, the present study measured the effects of alcohol on contrast discrimination and explored whether the deficits could be explained as a consequence of reduction in contrast gain. Detection thresholds and contrast increment thresholds under placebo and alcohol (0.06% BAC) conditions were measured in six volunteers. Alcohol was found to impair both detection and discrimination of only high spatial frequencies. However, when the base contrasts used in the increment threshold task were equal multiples of detection threshold, no alcohol-induced changes in increment thresholds were obtained at any spatial frequency. We conclude that alcohol impairs contrast discrimination performance but that no change in contrast gain mechanisms need be postulated to account for the data.

scholarly journals Ethyl 2-hydroxy-3-methylbutanoate enantiomers: quantitation and sensory evaluation in wine

OENO One ◽  
2018 ◽  
Vol 52 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Marine Gammacurta ◽  
Sophie Tempere ◽  
Stéphanie Marchand ◽  
Virginie Moine ◽  
Gilles De Revel
Keyword(s):  
Red Wine ◽  
Detection Threshold ◽  
Sensory Characteristics ◽  
Detection Thresholds ◽  
White Wines ◽  
Enantiomeric Ratio ◽  
Potential Marker ◽  
Significant Difference ◽  
Sensory Tests ◽  
Chiral Gas Chromatography

Aim: To investigate chemical and sensory characteristics of ethyl 2-hydroxy-3-methylbutanoate in wines.Methods and results: Ethyl 2-hydroxy-3-methylbutanoate has been recently identified as a potential marker of lactic acid bacteria esterase activity. Enantiomers of this fruity ester were quantitated in 99 wines from various vintages and French regions using chiral gas chromatography (γ-cyclodextrin phase). Analyses revealed the predominant presence of the R enantiomer in red and white wines, with a maximum R/S enantiomeric ratio of 94/6 in a 1993 red wine. Results also highlighted greater levels of the ester in red than white wines, depending on grape origin. The detection thresholds of the R- and S-form were estimated at 4 µg/L and 1.5 µg/L in water and 51 mg/L and 21 mg/L in red wine, respectively. Moreover, ranking tests made with levels found in wines did not show significant sensory differences.Conclusion: The concentrations found in wines were considerably below the detection threshold, indicating no direct effect of these compounds on fruity aroma modulation. The absence of significant difference in sensory tests demonstrates that ethyl 2-hydroxy-3-methylbutanoate does not contribute significantly to the fruity aroma of red wine.Significance and impact of the study: To our knowledge, no previous research had determined the enantiomeric distribution and the sensory characteristics of this compound in wine.

Dynamics of Adaptation to Contrast

Perception ◽  
1982 ◽  
Vol 11 (5) ◽  
pp. 505-528 ◽  
Author(s):  
David Rose ◽  
Ivan Lowe
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Power Function ◽  
Single Phase ◽  
Detection Threshold ◽  
High Spatial Frequency ◽  
Sinusoidal Grating ◽  
Dual Phase ◽  
High Contrast ◽  
Inhibitory Interactions

An investigation has been made into the temporal parameters with which the detection threshold for a sinusoidal grating changes during and after adaptation to the same grating at high contrast. Stationary high-spatial-frequency gratings and a phase-reversing low-spatial-frequency grating have been studied separately. It was found that the threshold continues to rise during adaptation for at least 6 min without sign of levelling off, and that full recovery from 6 min of adaptation can take more than 45 min. Intermittent adaptation and continuous adaptation for the same period produce similar effects. Single-phase and dual-phase exponential fits to the data are rejected, and it is concluded that the level of adaptation of the visual system to spatial contrast changes as a power function of time. However, recovery is not always monotonic, especially after adaptation to phase-reversing gratings. This may be due to inhibitory interactions between channels (in particular, those for pattern and movement information).

scholarly journals Advantage of the upper visual field for lateral interaction of high-spatial frequency

2010 ◽  
Vol 6 (6) ◽  
pp. 970-970
Author(s):  
Y. Tanaka ◽  
S. Miyauchi ◽  
M. Misaki ◽  
T. Tashiro
Keyword(s):  
Visual Field ◽  
Spatial Frequency ◽  
High Spatial Frequency ◽  
Lateral Interaction ◽  
Upper Visual Field

scholarly journals Changes and Diurnal Variation of Visual Quality after Orthokeratology in Myopic Children

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Hao-Chen Guo ◽  
Wan-Qing Jin ◽  
An-Peng Pan ◽  
Qin-Mei Wang ◽  
Jia Qu ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Diurnal Variation ◽  
High Spatial Frequency ◽  
Visual Quality ◽  
Spherical Equivalent ◽  
Corneal Curvature ◽  
Modulation Transfer ◽  
Wavefront Aberrations ◽  
Uncorrected Visual Acuity ◽  
High Order Aberrations

Purpose. To assess the changes and the diurnal variation of visual quality after orthokeratology in myopic children.Methods.Forty-four eyes of 22 subjects with a mean age of 10.55 ± 1.53 years (8 to 14 years) were enrolled in this prospective study. Their spherical equivalent ranged from −1.25 to −4.25 diopters (D) and astigmatism was less than 1.00 D. Parameters including corneal curvature, ocular objective scatter index (OSI), the modulation transfer function (MTF), root mean square of ocular and corneal wavefront aberrations, and contrast sensitivity function (CSF) were measured before and at two time points during the same day after 1 month of orthokeratology.Results. After orthokeratology, uncorrected visual acuity (UCVA) and spherical equivalent were significantly improved from baseline (P<0.001), and their diurnal variation was not significant (P=0.083,0.568). OSI increased from 0.29 ± 0.15 to 0.65 ± 0.31 (P<0.001). MTF decreased significantly (P<0.01). Corneal curvature and ocular total aberration decreased (P<0.001), while the ocular and corneal higher-order aberration increased significantly (P<0.01). The CSF under photopic condition decreased at 3 cpd (P=0.006) and increased at 18 cpd (P=0.012). The diurnal variation of CSF at 18 cpd under mesopic and high glare conditions and at 12 cpd under photopic condition was significant (P=0.002,0.01,0.017).Conclusions. Orthokeratology can effectively improve UCVA and high spatial frequency CSF by decreasing the low-order aberrations. However, MTF and CSF at low spatial frequency decreased because of the increase of intraocular scattering and high-order aberrations. Meanwhile, CSF at high spatial frequency fluctuates significantly at two times during the same day after 1 month orthokeratology.

Amblyopia Cannot Be Explained by considering Only Detection Thresholds

Perception ◽  
1980 ◽  
Vol 9 (5) ◽  
pp. 569-576 ◽  
Author(s):  
Robert Hess ◽  
Steven Jenkins
Keyword(s):  
Spatial Frequency ◽  
High Spatial Frequency ◽  
Threshold Function ◽  
Detection Thresholds ◽  
Frequency Threshold

Threshold function and suprathreshold performance for nonacuity stimuli are compared for an amblyope who exhibits a low as well as a high spatial frequency threshold abnormality. The results show that (i) a suprathreshold abnormality involving discrimination and localization of easily visible stimuli occurs in amblyopia and (ii) suprathreshold abnormalities occur in amblyopia independent of any threshold dysfunction.

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