Orientation Discrimination Research Articles

Non-image-forming photoreceptors improve visual orientation selectivity and image perception.

It has long been a decades-old dogma that image perception is mediated solely by rods and cones, while intrinsically photosensitive retinal ganglion cells (ipRGCs) are responsible only for non-image-forming vision, such as circadian photoentrainment and pupillary light reflexes. Surprisingly, we discovered that ipRGC activation enhances the orientation selectivity of layer 2/3 neurons in the primary visual cortex (V1) of mice by both increasing preferred-orientation responses and narrowing tuning bandwidth. Mechanistically, we found that the tuning properties of V1 excitatory and inhibitory neurons are differentially influenced by ipRGC activation, leading to a reshaping of the excitatory/inhibitory balance that enhances visual cortical orientation selectivity. Furthermore, light activation of ipRGCs improves behavioral orientation discrimination in mice. Importantly, we found that specific activation of ipRGCs in human participants through visual spectrum manipulation significantly enhances visual orientation discriminability. Our study reveals a visual channel originating from "non-image-forming photoreceptors" that facilitates visual orientation feature perception.

Comparing conventional and action video game training in visual perceptual learning

Action video game (AVG) playing has been found to transfer to a variety of laboratory tasks in visual cognition. More recently, it has even been found to transfer to low-level visual "psychophysics tasks. This is unexpected since such low-level tasks have traditionally been found to be largely “immune” to transfer from another task, or even from the same task but a different stimulus attribute, e.g., motion direction. In this study, we set out to directly quantify transfer efficiency from AVG training to motion discrimination. Participants (n = 65) trained for 20 h on either a first-person active shooting video game, or a motion direction discrimination task with random dots. They were tested before, midway, and after training with the same motion task and an orientation discrimination task that had been shown to receive transfer from AVG training, but not from motion training. A subsequent control group (n = 18) was recruited to rule out any test–retest effect, by taking the same tests with the same time intervals, but without training. We found that improvement in motion discrimination performance was comparable between the AVG training and control groups, and less than the motion discrimination training group. We could not replicate the AVG transfer to orientation discrimination, but this was likely due to the fact that our participants were practically at chance for this task at all test points. Our study found no evidence, in either accuracy or reaction time, that AVG training transferred to motion discrimination. Overall, our results suggest that AVG training transferred little to lower-level visual skills, refining understanding of the mechanisms by which AVGs may affect vision.Protocol registration The accepted stage 1 protocol for this study can be found on the Open Science Framework at https://osf.io/zdv9c/?view_only=5b3b0c161dad448d9d1d8b14ce91ab11.The stage 1 protocol for this Registered Report was accepted in principle on 01/12/22. The protocol, as accepted by the journal, can be found at: https://doi.org/10.17605/OSF.IO/ZDV9C

Sexual Orientation Discrimination in Early Adolescents

This cross-sectional study examined the prevalence of sexual orientation discrimination and its sociodemographic correlates among a large, diverse sample of early adolescents in the US.

Right visual field advantage in orientation discrimination is influenced by biased suppression

Visual input is not equally processed over space. In recent years, a right visual field advantage during free walking and standing in orientation discrimination and contrast detection task was reported. The current study investigated the underlying mechanism of the previously reported right visual field advantage. It particularly tested if the advantage is driven by a stronger suppression of distracting input from the left visual field or improved processing of targets from the right visual field. Combing behavioural and electrophysiological measurements in a mobile EEG and augmented reality setup, human participants (n = 30) in a standing and a walking condition performed a line orientation discrimination task with stimulus eccentricity and distractor status being manipulated. The right visual field advantage, as demonstrated in accuracy and reaction time, was influenced by the distractor status. Specifically, the right visual field advantage was only observed when the target had an incongruent line orientation with the distractor. Neural data further showed that the right visual field advantage was paralleled by a strong modulation of neural activity in the right hemisphere (i.e. contralateral to the distractor). A significant positive correlation between this right hemispheric event related potential (ERP) and behavioural measures (accuracy and reaction time) was found exclusively for trials in which a target was presented on the right and an incongruent distractor was presented on the left. The right hemispheric ERP component further predicted the strength of the right visual field advantage. Notably, the lateralised brain activity and the right visual field advantage were both independent of stimulus eccentricity and the movement state of participants. Overall, our findings suggest an important role of spatially biased suppression of left distracting input in the right visual field advantage as found in orientation discrimination.

Comparison of orientation encoding across layers within single columns of primate V1 revealed by high-density recordings.

Primary visual cortex (V1) has been the focus of extensive neurophysiological investigations, with its laminar organization serving as a crucial model for understanding the functional logic of neocortical microcircuits. Utilizing newly developed high-density, Neuropixels probes, we measured visual responses from large populations of simultaneously recorded neurons distributed across layers of macaque V1. Within single recordings, myriad differences in the functional properties of neuronal subpopulations could be observed. Notably, while standard measurements of orientation selectivity showed only minor differences between laminar compartments, decoding stimulus orientation from layer 4C responses outperformed both superficial and deep layers within the same cortical column. The superior orientation discrimination within layer 4C was associated with greater response reliability of individual neurons rather than lower correlated activity within neuronal populations. Our results underscore the efficacy of high-density electrophysiology in revealing the functional organization and network properties of neocortical microcircuits within single experiments.

Exposure-based Learning Improved Orientation Discrimination Under Visual Crowding

Exposure-based Learning Improved Orientation Discrimination Under Visual Crowding

Resting-state functional connectivity involved in tactile orientation processing

BackgroundGrating orientation discrimination (GOD) is commonly used to assess somatosensory spatial processing. It allows discrimination between parallel and orthogonal orientations of tactile stimuli applied to the fingertip. Despite its widespread application, the underlying mechanisms of GOD, particularly the role of cortico-cortical interactions and local brain activity in this process, remain elusive. Therefore, we aimed to investigate how a specific cortico-cortical network and inhibitory circuits within the primary somatosensory cortex (S1) and secondary somatosensory cortex (S2) contribute to GOD. MethodsIn total, 51 healthy young adults were included in our study. We recorded resting-state magnetoencephalography (MEG) and somatosensory-evoked magnetic field (SEF) in participants with open eyes. We converted the data into a source space based on individual structural magnetic resonance imaging. Next, we estimated S1- and S2-seed resting-state functional connectivity (rs-FC) at the alpha and beta bands through resting-state MEG using the amplitude envelope correlation method across the entire brain (i.e., S1/S2-seeds × 15,000 vertices × two frequencies). We assessed the inhibitory response in the S1 and S2 from SEFs using a paired-pulse paradigm. We automatically measured the GOD task in parallel and orthogonal orientations to the index finger, applying various groove widths with a custom-made device. ResultsWe observed a specific association between the GOD threshold (all P < 0.048) and the alpha rs-FC in the S1–superior parietal lobule and S1–adjacent to the parieto-occipital sulcus (i.e., lower rs-FC values corresponded to higher performance). In contrast, no association was observed between the local responses and the threshold. DiscussionThe results of this study underpin the significance of specific cortico-cortical networks in recognizing variations in tactile stimuli.

32 the Current State of Diversity and Workplace Experiences of Radiation Oncologists in Canada: A Survey of Gender Identity, Sexual Orientation, Disability, Race, Ethnicity, Religion, and Workplace Harassment and Discrimination

32 the Current State of Diversity and Workplace Experiences of Radiation Oncologists in Canada: A Survey of Gender Identity, Sexual Orientation, Disability, Race, Ethnicity, Religion, and Workplace Harassment and Discrimination

Neuronal and Behavioral Responses to Naturalistic Texture Images in Macaque Monkeys.

The visual world is richly adorned with texture, which can serve to delineate important elements of natural scenes. In anesthetized macaque monkeys, selectivity for the statistical features of natural texture is weak in V1, but substantial in V2, suggesting that neuronal activity in V2 might directly support texture perception. To test this, we investigated the relation between single cell activity in macaque V1 and V2 and simultaneously measured behavioral judgments of texture. We generated stimuli along a continuum between naturalistic texture and phase-randomized noise and trained two macaque monkeys to judge whether a sample texture more closely resembled one or the other extreme. Analysis of responses revealed that individual V1 and V2 neurons carried much less information about texture naturalness than behavioral reports. However, the sensitivity of V2 neurons, especially those preferring naturalistic textures, was significantly closer to that of behavior compared with V1. The firing of both V1 and V2 neurons predicted perceptual choices in response to repeated presentations of the same ambiguous stimulus in one monkey, despite low individual neural sensitivity. However, neither population predicted choice in the second monkey. We conclude that neural responses supporting texture perception likely continue to develop downstream of V2. Further, combined with neural data recorded while the same two monkeys performed an orientation discrimination task, our results demonstrate that choice-correlated neural activity in early sensory cortex is unstable across observers and tasks, untethered from neuronal sensitivity, and therefore unlikely to directly reflect the formation of perceptual decisions.

Recurrent inhibition refines mental templates to optimize perceptual decisions.

Translating sensory inputs to perceptual decisions relies on building internal representations of features critical for solving complex tasks. Yet, we still lack a mechanistic account of how the brain forms these mental templates of task-relevant features to optimize decision-making. Here, we provide evidence for recurrent inhibition: an experience-dependent plasticity mechanism that refines mental templates by enhancing γ-aminobutyric acid (GABA)-mediated (GABAergic) inhibition and recurrent processing in superficial visual cortex layers. We combine ultrahigh-field (7 T) functional magnetic resonance imaging at submillimeter resolution with magnetic resonance spectroscopy to investigate the fine-scale functional and neurochemical plasticity mechanisms for optimized perceptual decisions. We demonstrate that GABAergic inhibition increases following training on a visual (i.e., fine orientation) discrimination task, enhancing the discriminability of orientation representations in superficial visual cortex layers that are known to support recurrent processing. Modeling functional and neurochemical plasticity interactions reveals that recurrent inhibitory processing optimizes brain computations for perpetual decisions and adaptive behavior.

Neural Substrates for Early Data Reduction in Fast Vision: A Psychophysical Investigation.

To ensure survival, the visual system must rapidly extract the most important elements from a large stream of information. This necessity clashes with the computational limitations of the human brain, so a strong early data reduction is required to efficiently process information in fast vision. A theoretical early vision model, recently developed to preserve maximum information using minimal computational resources, allows efficient image data reduction by extracting simplified sketches containing only optimally informative, salient features. Here, we investigate the neural substrates of this mechanism for optimal encoding of information, possibly located in early visual structures. We adopted a flicker adaptation paradigm, which has been demonstrated to specifically impair the contrast sensitivity of the magnocellular pathway. We compared flicker-induced contrast threshold changes in three different tasks. The results indicate that, after adapting to a uniform flickering field, thresholds for image discrimination using briefly presented sketches increase. Similar threshold elevations occur for motion discrimination, a task typically targeting the magnocellular system. Instead, contrast thresholds for orientation discrimination, a task typically targeting the parvocellular system, do not change with flicker adaptation. The computation performed by this early data reduction mechanism seems thus consistent with magnocellular processing.

Discrimination and hypertension among a diverse sample of racial and sexual minority men living with HIV: baseline findings of a longitudinal cohort study

Racial and sexual orientation discrimination may exacerbate the double epidemic of hypertension (HTN) and HIV that affects men of color who have sex with men (MSM). This was a cross-sectional analysis of African American, Asian American, Native Hawaiian, or Pacific Islander (NHPI) MSM living with HIV (PLWH) cohort in Honolulu and Philadelphia. Racial and sexual orientation discrimination, stress, anxiety, and depression were measured with computer-assisted self-interview questionnaires (CASI). We examined the associations between racial and sexual orientation discrimination with hypertension measured both in the office and by 24-h ambulatory blood pressure monitoring (ABPM) using multivariable logistic regression. Sixty participants (60% African American, 18% Asian, and 22% NHPI) completed CASIs and 24-h ABPM. African American participants (80%) reported a higher rate of daily racial discrimination than Asian American (36%) and NHPI participants (17%, p < 0.001). Many participants (51%) reported daily sexual orientation discrimination. Sixty-six percent of participants had HTN by office measurement and 59% had HTN by 24-h ABPM measurement. Participants who experienced racial discrimination had greater odds of having office-measured HTN than those who did not, even after adjustment (Odds Ratio 5.0 (95% Confidence Interval [1.2–20.8], p = 0.03)). This association was not seen with 24-h ABPM. Hypertension was not associated with sexual orientation discrimination. In this cohort, MSM of color PLWH experience significant amounts of discrimination and HTN. Those who experienced racial discrimination had higher in-office blood pressure. This difference was not observed in 24-h APBM and future research is necessary to examine the long-term cardiovascular effects.

Experiences with Sexual Orientation and Gender Identity Employment Discrimination in the USA: Analyzing EEOC Discrimination Charge Narratives

Experiences with Sexual Orientation and Gender Identity Employment Discrimination in the USA: Analyzing EEOC Discrimination Charge Narratives

Same‐Sex Unions in Hong Kong and the Misuse of Comparative Law: Sham Tsz Kit v Secretary for Justice

In 2023, the Hong Kong Court of Final Appeal (CFA) handed down a significant decision requiring the creation of an alternative legal framework to recognise same‐sex unions. The judgment marked the culmination of two decades of strategic litigation challenging various forms of sexual orientation discrimination in Hong Kong, yet it fell short of recognising same‐sex marriage. The CFA's rejection was based upon an originalist construction of the Hong Kong Basic Law, the city's ‘mini constitution’, alongside a comparative analysis of select supranational human rights regimes. This note reflects upon the interpretive techniques used by the CFA and interrogates its reasons for denying the existence of a constitutional right to same‐sex marriage in Hong Kong. It argues that the CFA's use of an originalist construction was misplaced and inconsistent with its prior jurisprudence. The note also reflects on the CFA's selective use of comparative and international law, and the hazards associated with using external sources to control the interpretation of domestic public law norms.

Religious discrimination at the CJEU and the social inclusion approach

The social inclusion approach to EU anti-discrimination law, as set out by Ringelheim, is aimed at achieving inclusion and participation in employment and wider society of all groups, including the most disadvantaged. But is the CJEU using this social inclusion approach, especially in cases concerning religious discrimination? This article argues that the CJEU, in cases regarding racial and ethnic origin, disability and sexual orientation discrimination as well as in some cases regarding religion or belief discrimination, has indeed applied a social inclusion approach, but that the six judgments regarding the wearing of Islamic headscarves at work are an exception. In the latter cases, the CJEU did not appear to pay any attention to the effect of the judgments on the employment opportunities of Muslim women who want to wear religious symbols at work.

Do microsaccades vary with discriminability around the visual field?

Microsaccades-tiny fixational eye movements-improve discriminability in high-acuity tasks in the foveola. To investigate whether they help compensate for low discriminability at the perifovea, we examined microsaccade characteristics relative to the adult visual performance field, which is characterized by two perceptual asymmetries: horizontal-vertical anisotropy (better discrimination along the horizontal than vertical meridian) and vertical meridian asymmetry (better discrimination along the lower than upper vertical meridian). We investigated whether and to what extent microsaccade directionality varies when stimuli are at isoeccentric locations along the cardinals under conditions of heterogeneous discriminability (Experiment 1) and homogeneous discriminability, equated by adjusting stimulus contrast (Experiment 2). Participants performed a two-alternative forced-choice orientation discrimination task. In both experiments, performance was better on trials without microsaccades between ready signal onset and stimulus offset than on trials with microsaccades. Across the trial sequence, the microsaccade rate and directional pattern were similar across locations. Our results indicate that microsaccades were similar regardless of stimulus discriminability and target location, except during the response period-once the stimuli were no longer present and target location no longer uncertain-when microsaccades were biased toward the target location. Thus, this study reveals that microsaccades do not flexibly adapt as a function of varying discriminability in a basic visual task around the visual field.

Digital therapeutics using virtual reality-based visual perceptual learning for visual field defects in stroke: A double-blind randomized trial.

Visual field defects (VFDs) represent a debilitating poststroke complication, characterized by unseen parts of the visual field. Visual perceptual learning (VPL), involving repetitive visual training in blind visual fields, may effectively restore visual field sensitivity in cortical blindness. This current multicenter, double-blind, randomized, controlled clinical trial investigated the efficacy and safety of VPL-based digital therapeutics (Nunap Vision [NV]) for treating poststroke VFDs. Stroke outpatients with VFDs (>6 months after stroke onset) were randomized into NV (defective field training) or Nunap Vision-Control (NV-C, central field training) groups. Both interventions provided visual perceptual training, consisting of orientation, rotation, and depth discrimination, through a virtual reality head-mounted display device 5 days a week for 12 weeks. The two groups received VFD assessments using Humphrey visual field (HVF) tests at baseline and 12-week follow-up. The final analysis included those completed the study (NV, n=40; NV-C, n=35). Efficacy measures included improved visual area (sensitivity ≥6dB) and changes in the HVF scores during the 12-week period. With a high compliance rate, NV and NV-C training improved the visual areas in the defective hemifield (>72 degrees2) and the whole field (>108 degrees2), which are clinically meaningful improvements despite no significant between-group differences. According to within-group analyses, mean total deviation scores in the defective hemifield improved after NV training (p=.03) but not after NV-C training (p=.12). The current trial suggests that VPL-based digital therapeutics may induce clinically meaningful visual improvements in patients with poststroke VFDs. Yet, between-group differences in therapeutic efficacy were not found as NV-C training exhibited unexpected improvement comparable to NV training, possibly due to learning transfer effects.

Socio-Economic Status of Women Teachers Employees in India

Abstract: Sexual orientation discrimination in India is the chief reason that has influenced women's socio- economic turn of events. Women in country territories are known to need sufficient offices and education for their turn of events. Most women in country zones have less access to social insurance. Most of women in towns are housewives and work for their occupation in the homestead division. In this study we concentrated on the socio-economic status of women employees of women teachers. The point of this study is to choose the distinction between the economic and cultural position, the association between the fragment status of women teachers and their economic prosperity, the association between the portion status of women teachers and their economic status, and to study the association between the profile components of women teachers and their social position. In the current study we inspect the relationship between the elements of the profile of the female teachers and their satisfaction at work. For this study the A pilot test was conducted and corrections were made in the questionnaire, as were other sources, for example, journals, papers, diaries, reports, articles and related investigations. The scientist gathered information from 300 female respondents picked utilizing a delineated irregular inspecting method. Among the 300 women respondents, 245 are working on a regular basis and 55 are on temporary/Guest basis. Random sampling method to distribute questionnaires was followed by the researcher, and user data was obtained. From the study one can see that strong measures are expected to upgrade the socio-economic status of women instructor employees. Women are intensely tried out advanced education and business. It might be because of government concerns in education and work, and Women's Universities and Colleges being established. In spite of the fact that their proportion is high, contrasted with that of guys, their rank isn't high. Various factors, for example, age, sexual orientation, religion, conjugal status, number of wards, scholarly qualifications, specialized qualifications, position, sort of school, nature of occupation and number of long stretches of experience influence the status of women instructor employees. Along these lines it is essential to improve the socio-economic conditions of women teachers. Female teachers ought to endeavor to find some kind of harmony between their work and family jobs. In addition to encouraging they ought not stop for a second to accept obligations. It builds their organizationalstatus as well as energizes their trust in themselves. Through taking part in different preparing programs, addresses, conferences, workshops and taking up further study courses they can findout to an ever increasing extent

Task demand mediates the interaction of spatial and temporal attention

Psychophysical studies typically test attentional mechanisms in isolation, but in everyday life they interact to optimize human behavior. We investigated whether spatial and temporal attention interact in two orientation discrimination experiments that vary in task demand. We manipulated temporal and spatial attention separately and conjointly with well-established methods for testing each spatial or temporal attention. We assessed sensitivity (d′) and reaction time for every combination of spatial and timing cues, each of which was valid, neutral, or invalid. Spatial attention modulated sensitivity (d′) and speed (reaction time) across temporal attention conditions. Temporal attention modulated sensitivity and speed under high- but not low- task demands. Furthermore, spatial and temporal attention interacted for the high-demand task. This study reveals that task demand matters; in a simple task spatial attention suffices to improve performance, whereas in a more demanding task both spatial and temporal attention interact to boost performance, albeit in a subadditive fashion.

A Scoping Review on Heteronormativity in African Workplaces

The increasing globalisation of the corporate world has intensified interactions among individuals from diverse backgrounds. One significant change in the workplace is the increased participation of LGBTQ+ employees in contemporary organisations. Despite the progress made in recognising the rights of sexual minorities in some African countries, there remains a prevalent issue of sexual orientation discrimination, grounded in the belief that heterosexuality is the societal norm, a concept known as heteronormativity. Existing literature underscores the pervasive discrimination based on sexual orientation, which negatively affects the well-being and work performance of LGBTQ+ employees. While some individuals find happiness and meaning despite these challenges, research in the African context remains limited. This article conducts a scoping review to synthesise Afrocentric evidence on heteronormativity in the workplace. The review explores how heteronormativity manifests, is reinforced, and impacts on individuals and organisations within the African context. The article further examines how LGBTQ+ employees navigate this heteronormative work environment. This scoping review identifies and analyses 13 studies focusing primarily on African countries, revealing discrimination, gender inequality, sexism, and workplace heteronormativity as common themes. These themes emphasise the need for comprehensive approaches to promote equitable, diverse, and inclusive workplaces in Africa, recognising the unique challenges within this context. The findings underscore the urgency of addressing heteronormative norms to construct more inclusive and equitable workplaces for all.