Multisensory effects of mask wearing on speech intelligibility and the benefit of multilingualism

PURPOSE

Due to the pandemic of the Covid-19 disease, it became common to wear masks on some public spaces. By covering mouth and nose, visual-related speech cues are greatly reduced, while the auditory signal is both distorted and attenuated. The present study aimed to analyze the multisensory effects of mask wearing on speech intelligibility and the differences in these effects between participants who spoke 1, 2 and 3 languages.

METHODS

The study consisted of the presentation of sentences from the SPIN test to 40 participants. Participants were asked to report the perceived sentences. There were four conditions: auditory with mask; audiovisual with mask; auditory without mask; audiovisual without mask. Two sessions were conducted, one week apart, each with the same stimuli but with a different signal-to-noise ratio.

RESULTS

Results demonstrated that the use of the mask decreased speech intelligibility, both due to a decrease in the quality of auditory stimuli and due to the loss of visual information. Signal-to-noise ratio largely affects speech intelligibility and higher ratios are needed in mask-wearing conditions to obtain any degree of intelligibility. Those who speak more than one language are less affected by mask wearing, as are younger listeners.

CONCLUSION

Wearing a facial mask reduces speech intelligibility, both due to visual and auditory factors. Older people and people who only speak one language are affected the most.

Two Sides of the Same Coin: Efficient and Predictive Neural Coding

Some visual properties are consistent across a wide range of environments, while other properties are more labile. The efficient coding hypothesis states that many of these regularities in the environment can be discarded from neural representations, thus allocating more of the brain's dynamic range to properties that are likely to vary. This paradigm is less clear about how the visual system prioritizes different pieces of information that vary across visual environments. One solution is to prioritize information that can be used to predict future events, particularly those that guide behavior. The relationship between the efficient coding and future prediction paradigms is an area of active investigation. In this review, we argue that these paradigms are complementary and often act on distinct components of the visual input. We also discuss how normative approaches to efficient coding and future prediction can be integrated.

Disparities in Eye Care Access and Utilization: A Narrative Review

This narrative review summarizes the literature on factors related to eye care access and utilization in the United States. Using the Healthy People 2030 framework, this review investigates social determinants of health associated with general and follow-up engagement, screenings, diagnostic visits, treatment, technology, and teleophthalmology. We provide hypotheses for these documented eye care disparities, featuring qualitative, patient-centered research. Lastly, we provide recommendations in the hopes of appropriately eliminating these disparities and reimagining eye care.

Visual Functions of the Primate Superior Colliculus

The superior colliculus (SC) is a subcortical brain structure that is relevant for sensation, cognition, and action. In nonhuman primates, a rich history of studies has provided unprecedented detail about this structure's role in controlling orienting behaviors; as a result, the primate SC has become primarily regarded as a motor control structure. However, as in other species, the primate SC is also a highly visual structure: A fraction of its inputs is retinal and complemented by inputs from visual cortical areas, including the primary visual cortex. Motivated by this, recent investigations are revealing the rich visual pattern analysis capabilities of the primate SC, placing this structure in an ideal position to guide orienting movements. The anatomical proximity of the primate SC to both early visual inputs and final motor control apparatuses, as well as its ascending feedback projections to the cortex, affirms an important role for this structure in active perception.

Sensory functions and their relation to balance metrics: a secondary analysis of the LIMBIC-CENC multicenter cohort

Introduction

Among patients with traumatic brain injury (TBI), balance problems often persist alongside hearing and vision impairments that lead to poorer outcomes of functional independence. As such, the ability to regain premorbid independent gait may be dictated by the level of sensory acuity or processing decrements that are shown following TBI assessment. This study explores the relationships between standardized sensory acuity and processing outcomes to postural balance and gait speed.

Methods

Secondary analysis was performed on the Long-Term Impact of Military- Relevant Brain Injury Consortium Chronic Effects of Neurotrauma Consortium LIMBIC (CENC) data set. Separate regression analyses were carried out for each of the balance assessments (via Computerized Dynamic Posturography, CDP) and walking speed.

Discussion

TBI frequency was significantly related to the majority of single CDP outcomes (i.e., Conditions 2-6), while various sensory processing outcomes had task-specific influences. Hearing impairments and auditory processing decrements presented with lower CDP scores (CDP Conditions 3,5,6, and 1-3 respectively), whereas greater visual processing scores were associated with better CDP scores for Conditions 2,5, and 6. In sum, patients with TBI had similar scores on static balance tests compared to non-TBI, but when the balance task got more difficult patients with TBI scored worse on the balance tests. Additionally, stronger associations with sensory processing than sensory acuity measures may indicate that patients with TBI have increased fall risk.

Different sensory information is used for state estimation when stationary or moving

Accurate estimation of limb state is necessary for movement planning and execution. State estimation requires both feedforward and feedback information; here we focus on the latter. Prior literature has shown that integrating visual and proprioceptive feedback improve estimates of static limb position. However, differences in visual and proprioceptive feedback delays suggest that multisensory integration could be disadvantageous when the limb is moving. To investigate multisensory integration in different passive movement contexts, we compared the degree of interference created by discrepant visual or proprioceptive feedback when estimating the position of the limb either statically at the end of the movement or dynamically at movement midpoint. In the static context, we observed idiosyncratic interference: discrepant proprioceptive feedback significantly interfered with reports of the visual target location, leading to a bias of the reported position toward the proprioceptive cue. In the dynamic context, no interference was seen: participants could ignore sensory feedback from one modality and accurately reproduce the motion indicated by the other modality. We modeled feedback-based state estimation by updating the longstanding maximum likelihood estimation model of multisensory integration to account for sensory delays. Consistent with our behavioral results, the model showed that the benefit of multisensory integration was largely lost when the limb was passively moving. Together, these findings suggest that the sensory feedback used to compute a state estimate differs depending on whether the limb is stationary or moving. While the former may tend toward multimodal integration, the latter is more likely to be based on feedback from a single sensory modality.

Visual attention to features and space in mice using reverse correlation

Visual attention allows the brain to evoke behaviors based on the most important visual features. Mouse models offer immense potential to gain a circuit-level understanding of this phenomenon, yet how mice distribute attention across features and locations is not well understood. Here, we describe a new approach to address this limitation by training mice to detect weak vertical bars in a background of dynamic noise while spatial cues manipulate their attention. By adapting a reverse-correlation method from human studies, we linked behavioral decisions to stimulus features and locations. We show that mice deployed attention to a small rostral region of the visual field. Within this region, mice attended to multiple features (orientation, spatial frequency, contrast) that indicated the presence of weak vertical bars. This attentional tuning grew with training, multiplicatively scaled behavioral sensitivity, approached that of an ideal observer, and resembled the effects of attention in humans. Taken together, we demonstrate that mice can simultaneously attend to multiple features and locations of a visual stimulus.

A "Bandwidth" in cortical representations of multiple faces

The human ability to process multiple items simultaneously can be constrained by the extent to which those items are represented by distinct neural populations. In the current study, we used fMRI to investigate the cortical representation of multiple faces. We found that the addition of a second face to occupy both visual hemifields led to an increased response, whereas a further addition of faces within the same visual hemifield resulted in a decreased response. This pattern was widely observed in the occipital visual cortex, the intraparietal sulcus, and extended to the posterior inferotemporal cortex. A parallel trend was found in a behavioral change-detection task, revealing a perceptual "bandwidth" of multiface processing. The sensitivity to face clutter gradually decreased along the ventral pathway, supporting the notion of a buildup of clutter-tolerance representation. These cortical response patterns to face clutters suggest that adding signals with nonoverlapping cortical representation enhanced perception, while adding signals that competed for representation resources impaired perception.

Fixational Eye Movements Enhance the Precision of Visual Information Transmitted by the Primate Retina

Fixational eye movements alter the number and timing of spikes transmitted from the retina to the brain, but whether these changes enhance or degrade the visual signal is unclear. To quantify this, we developed a Bayesian method for reconstructing natural images from the recorded spikes of hundreds of macaque retinal ganglion cells (RGCs) of the major cell types, combining a likelihood model for RGC light responses with the natural image prior implicitly embedded in an artificial neural network optimized for denoising. The method matched or surpassed the performance of previous reconstruction algorithms, and provided an interpretable framework for characterizing the retinal signal. Reconstructions were improved with artificial stimulus jitter that emulated fixational eye movements, even when the jitter trajectory was inferred from retinal spikes. Reconstructions were degraded by small artificial perturbations of spike times, revealing more precise temporal encoding than suggested by previous studies. Finally, reconstructions were substantially degraded when derived from a model that ignored cell-to-cell interactions, indicating the importance of stimulus-evoked correlations. Thus, fixational eye movements enhance the precision of the retinal representation.

Visual dysfunction is a better predictor than retinal thickness for dementia in Parkinson's disease

BACKGROUND

Dementia is a common and devastating symptom of Parkinson's disease (PD). Visual function and retinal structure are both emerging as potentially predictive for dementia in Parkinson's but lack longitudinal evidence.

METHODS

We prospectively examined higher order vision (skew tolerance and biological motion) and retinal thickness (spectral domain optical coherence tomography) in 100 people with PD and 29 controls, with longitudinal cognitive assessments at baseline, 18 months and 36 months. We examined whether visual and retinal baseline measures predicted longitudinal cognitive scores using linear mixed effects models and whether they predicted onset of dementia, death and frailty using time-to-outcome methods.

RESULTS

Patients with PD with poorer baseline visual performance scored lower on a composite cognitive score (β=0.178, SE=0.05, p=0.0005) and showed greater decreases in cognition over time (β=0.024, SE=0.001, p=0.013). Poorer visual performance also predicted greater probability of dementia (χ² (1)=5.2, p=0.022) and poor outcomes (χ² (1) =10.0, p=0.002). Baseline retinal thickness of the ganglion cell-inner plexiform layer did not predict cognitive scores or change in cognition with time in PD (β=-0.013, SE=0.080, p=0.87; β=0.024, SE=0.001, p=0.12).

CONCLUSIONS

In our deeply phenotyped longitudinal cohort, visual dysfunction predicted dementia and poor outcomes in PD. Conversely, retinal thickness had less power to predict dementia. This supports mechanistic models for Parkinson's dementia progression with onset in cortical structures and shows potential for visual tests to enable stratification for clinical trials.

Clinical outcomes of trifocal toric intraocular lenses

The purpose of this report is to summarize the visual and refractive outcomes of patients with trifocal toric intraocular lens (IOL) implants. A peer-reviewed literature search in different databases was carried out to identify clinical publications reporting outcomes of patients with this type of implant. The analysis considered information on the sample of eyes, type and power of the trifocal toric IOLs, biometric preoperative data, postoperative refraction, rotational stability, visual acuity at different distances and other analyses undertaken, such as contrast sensitivity or quality of vision questionnaires. 20 clinical studies, encompassing a total of 1404 eyes implanted with three commercially available trifocal toric IOLs, were included in this review. The analysis assessed the outcomes reported for the AT LISA tri toric 939MP IOL, involving 3 articles and 313 eyes; the FineVision toric POD FT IOL, with 7 articles studying 370 eyes, and the AcrySof IQ PanOptix toric IOL, involving 11 articles and 721 eyes. Our assessment of the outcomes of the various studies indicates that the efficacy of the refractive correction (both sphere and cylinder) and visual acuity at different distances was similar between the IOL models. The same was found for the patients' quality of vision and satisfaction levels, in addition to photic phenomena reported. The outcomes summarized in this report lead us to conclude that the use of trifocal toric IOLs allows complete visual restoration over a wide range of distances.

Influences of local and global context on local orientation perception

Visual context modulates perception of local orientation attributes. These spatially very localised effects are considered to correspond to specific excitatory-inhibitory connectivity patterns of early visual areas as V1, creating perceptual tilt repulsion and attraction effects. Here, orientation misperception of small Gabor stimuli was used as a probe of this computational structure by sampling a large spatio-orientation space to reveal expected asymmetries due to the underlying neuronal processing. Surprisingly, the results showed a regular iso-orientation pattern of nearby location effects whose reference point was globally modulated by the spatial structure, without any complex interactions between local positions and orientation. This pattern of results was confirmed by the two perceptual parameters of bias and discrimination ability. Furthermore, the response times to stimulus configuration displayed variations that further provided evidence of how multiple early visual stages affect perception of simple stimuli.

Artificial light at night decreases the pupillary light response of dark-adapted toads to bright light

Artificial light at night (ALAN) is expanding worldwide. Many physiological effects have been reported in animals, but we still know little about the consequences for the visual system. The pupil contributes to control incoming light onto the retina. Sudden increases in light intensity evokes the pupil light reflex (PLR). Intrinsically photosensitive retinal ganglion cells (ipRGC) affect PLR and melatonin expression, which largely regulate circadian rhythms and PLR itself. IpRCG receive inputs from various photoreptors with different peak sensitivities implying that PLR could be altered by a broad range of light sources. We predicted ALAN to enhance PLR. Contrary to our prediction, dark-adapted cane toads Rhinella marina, exposed to ALAN (5 lx) for 12 days, exhibited a lower PLR than controls and individuals exposed to 0.04 lx, even after 1 h in bright light. We cannot conclude whether ALAN induced a larger pupil size in dark-adapted toads or a slower initial contraction. Nevertheless, the response was triggered by a light source with an emission peak (590 nm) well above the sensitivity peak of melanopsin, the main photoreceptor involved in PLR. Therefore, ALAN alters the capacity of toads to regulate the incoming light in the eye at night, which may reduce the performance of visually guided behaviors, and increase mortality by predators or road kills at night. This first study emphasizes the need to focus on the effect of ALAN on the vision of nocturnal organisms to better understand how this sensory system is altered and anticipate the consequences for organisms.

Primary eyecare provision for people living with dementia: what do we need to know?

Dementia comprises a group of brain disorders characterised by loss of cognitive function. Sensory loss, predominantly vision (the focus of this review) and hearing, is a significant problem for people living with dementia. Eyecare practitioners such as optometrists therefore play an important role in identifying and addressing vision-related care needs. To support provision of high quality "dementia-friendly" eyecare, this scoping review summarises recent primary research findings and available clinical practice guidelines, to identify research gaps relating to vision and dementia, and make recommendations for future research and clinical practice. The review set a priori guidelines for the population, concept and context based on the review questions. Primary research papers (2016-2021) were included via 3-step search strategy: preliminary search to index terms, full search, search reference lists of included articles for further inclusions. Additionally, websites of eyecare professional bodies in English-speaking countries were searched to identify current clinical eyecare practice guidelines relating to dementia. Study characteristics (e.g. country, study design) were reported descriptively. Patterns within findings/recommendations from included sources were identified using thematic analysis and reported as themes. 1651 titles/abstracts and 161 full-text articles were screened for eligibility. Three clinical practice guidelines were also identified. The final review included 21 sources: 18 primary research papers and 3 clinical practice guidelines. The thematic analysis reported five key themes: Diagnosis/Screening, dementia progression, findings on clinical visual testing, tailored approach to care, improving care. This scoping review demonstrated limited information about current practices of optometrists working with people living with dementia. Recent evidence reinforces the continuing need for improved eyecare for people living with dementia, taking into account their specific needs with an individualised approach. Up-to-date practical recommendations are synthesised for eyecare providers before, during and after a consultation with a person living with dementia, to better support their care.

Bilateral arm movements are coordinated via task-dependent negotiations between independent and codependent control, but not by a "coupling" control policy

Prior research has shown that coordination of bilateral arm movements might be attributed to either control policies that minimize performance and control costs regardless of bilateral symmetry or by control coupling, which activates bilaterally homologous muscles as a single unit to achieve symmetric performance. We hypothesize that independent bimanual control (movements of one arm are performed without influence on the other) and codependent bimanual control (two arms are constrained to move together with high spatiotemporal symmetry) are two extremes on a coordination spectrum that can be negotiated to meet infinite variations in task demands. To better understand and distinguish between these views, we designed a task where minimization of either control costs or asymmetry would yield different patterns of coordination. Participants made bilateral reaches with a shared visual cursor to a midline target. We then covertly varied the gain contribution of either hand to the shared cursor's horizontal position. Across two experiments, we show that bilateral coordination retains high task-dependent sensitivity to subtle visual feedback gain asymmetries applied to the shared cursor. Specifically, we found a change from strong spatial covariation between hands during equal gains to more independent control during asymmetric gains, which occurred rapidly and with high specificity to the dimension of gain manipulation. Furthermore, the extent of spatial covariation was graded to the magnitude of perpendicular gain asymmetry between hands. These findings suggest coordination of bilateral arm movements flexibly maneuvers along a continuous coordination spectrum in a task-dependent manner that cannot be explained by bilateral control coupling.NEW & NOTEWORTHY Minimization of performance and control costs and efferent coupling between bilaterally homologous muscle groups have been separately hypothesized to describe patterns of bimanual coordination. Here, we address whether the mechanisms mediating independent and codependent control between limbs can be weighted for successful task performance. Using bilaterally asymmetric visuomotor gain perturbations, we show bimanual coordination can be characterized as a negotiation along a spectrum between extremes of independent and codependent control, but not efferent control coupling.

Network Localization of Awareness in Visual and Motor Anosognosia

OBJECTIVE

Unawareness of a deficit, anosognosia, can occur for visual or motor deficits and lends insight into awareness itself; however, lesions associated with anosognosia occur in many different brain locations.

METHODS

We analyzed 267 lesion locations associated with either vision loss (with and without awareness) or weakness (with and without awareness). The network of brain regions connected to each lesion location was computed using resting-state functional connectivity from 1,000 healthy subjects. Both domain specific and cross-modal associations with awareness were identified.

RESULTS

The domain-specific network for visual anosognosia demonstrated connectivity to visual association cortex and posterior cingulate while motor anosognosia was defined by insula, supplementary motor area, and anterior cingulate connectivity. A cross-modal anosognosia network was defined by connectivity to the hippocampus and precuneus (false discovery rate p < 0.05).

INTERPRETATION

Our results identify distinct network connections associated with visual and motor anosognosia and a shared, cross-modal network for awareness of deficits centered on memory-related brain structures. ANN NEUROL 2023;94:434-441.

Erratum: Covariance properties under natural image transformations for the generalised Gaussian derivative model for visual receptive fields

[This corrects the article DOI: 10.3389/fncom.2023.1189949.].

Perceptual Awareness Occurs Along a Graded Continuum: No Evidence of All-or-None Failures in Continuous Reproduction Tasks

Does sensory information reach conscious awareness in a discrete, all-or-nothing manner or a gradual, continuous manner? To answer this question, we examined behavioral performance across four different paradigms that manipulate visual awareness: the attentional blink, backward masking, the Sperling iconic memory paradigm, and retro-cuing. We then asked how well we could account for participants' (N = 112 adults) behavior using a signal detection framework that factors in psychophysical scaling to model participants' responses along a single continuum. We found that this model easily accounted for the data from each of these diverse paradigms. Moreover, we reanalyzed the data from prior studies that had posited a discrete view of perceptual awareness and found that our continuous signal detection model outperformed the models that had been used to support an all-or-nothing view of consciousness. This set of data is consistent with the idea that conscious awareness occurs along a graded continuum.

An Open-Field-Based Unimodal Object Recognition Test (OF-UORT) for Assessment of Chronic Stress Effects on Visual and Tactile Unimodal Cognition in Mice

The open field (OF) test is a widely used behavioral assay in animal studies to assess locomotion, emotion, and cognition. In open-field-based object recognition tasks, the open arena is equipped with combinations of objects to allow the examination of various aspects of learning and memory. In this article, we provide a protocol for open-field-based unimodal memory tests that assess tactile or visual unimodal cognitive behavior in mice. These tests do not require mice to be restricted from eating or drinking and do not involve aversive stimuli, such as electric shock, high-decibel sound waves, bright light, or forced swimming. Inside the apparatus, mice can freely and spontaneously explore the objects and the environment. Sniffing of, or direct contact with, objects is considered a cognitive exploration of the objects, and the timing and number of such behaviors can be recorded. During the acquisition phase, two identical objects are provided. After an intertrial interval, the retrieval phase is initiated, during which one object is replaced with a new object that is different from the previous one. Decorative clear domes are used prevent direct tactile contact with the objects, whereas infrared illumination is used to block visual information from the objects. By alternating the access to visual or tactile features of the objects in the acquisition and retrieval phases, the experimenters can assess visual or tactile unimodal cognition. Here, we describe our own instrumentation and application for experiments, and demonstrate that the modified device is capable of testing visual or tactile unimodal cognition in mice. Although easy to perform, this task/test can accurately reflect unimodal cognitive performance in mice, which can provide solid and reproducible data support to related studies. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Validation of the open-field-based unimodal object recognition test Basic Protocol 2: Evaluation of chronic stress effects on unimodal cognition using the open-field-based unimodal cognitive test.

Clinically relevant factors associated with a binary outcome of diabetic macular ischaemia: an OCTA study

AIMS

We investigated the demographic, ocular, diabetes-related and systemic factors associated with a binary outcome of diabetic macular ischaemia (DMI) as assessed by optical coherence tomography angiography (OCTA) evaluation of non-perfusion at the level of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in a cohort of patients with diabetes mellitus (DM).

MATERIALS AND METHODS

617 patients with DM were recruited from July 2015 to December 2020 at the Chinese University of Hong Kong Eye Centre. Image quality assessment (gradable or ungradable for assessing DMI) and DMI evaluation (presence or absence of DMI) were assessed at the level of the SCP and DCP by OCTA.

RESULTS

1107 eyes from 593 subjects were included in the final analysis. 560 (50.59%) eyes had DMI at the level of SCP, and 647 (58.45%) eyes had DMI at the level of DCP. Among eyes without diabetic retinopathy (DR), DMI was observed in 19.40% and 24.13% of eyes at SCP and DCP, respectively. In the multivariable logistic regression models, older age, poorer visual acuity, thinner ganglion cell-inner plexiform layer thickness, worsened DR severity, higher haemoglobin A1c level, lower estimated glomerular filtration rate and higher low-density lipoprotein cholesterol level were associated with SCP-DMI. In addition to the aforementioned factors, presence of diabetic macular oedema and shorter axial length were associated with DCP-DMI.

CONCLUSION

We reported a series of associated factors of SCP-DMI and DCP-DMI. The binary outcome of DMI might promote a simplified OCTA-based DMI evaluation before subsequent quantitative analysis for assessing DMI extent and fulfil the urge for an updating diabetic retinal disease staging to be implemented with OCTA.

Availability of Physical Activity Tracking Data from Wearable Devices for Glaucoma Patients

Physical activity has been found to potentially modulate glaucoma risk, but the evidence remains inconclusive. The increasing use of wearable physical activity trackers may provide longitudinal and granular data suitable to address this issue, but little is known regarding the characteristics and availability of these data sources. We performed a scoping review and query of data sources on the availability of wearable physical activity data for glaucoma patients. Literature databases (PubMed and MEDLINE) were reviewed with search terms consisting of those related to physical activity trackers and those related to glaucoma, and we evaluated results at the intersection of these two groups. Biomedical databases were also reviewed, for which we completed database queries. We identified eight data sources containing physical activity tracking data for glaucoma, with two being large national databases (UK BioBank and All of Us) and six from individual journal articles providing participant-level information. The number of glaucoma patients with physical activity tracking data available, types of glaucoma-related data, fitness devices utilized, and diversity of participants varied across all sources. Overall, there were limited analyses of these data, suggesting the need for additional research to further investigate how physical activity may alter glaucoma risk.

Task Instructions and the Need for Feedback Correction Influence the Contribution of Visual Errors to Reach Adaptation

Previous research has questioned whether motor adaptation is shaped by an optimal combination of multisensory error signals. Here, we expanded on this work by investigating how the use of visual and somatosensory error signals during online correction influences single-trial adaptation. To this end, we exposed participants to a random sequence of force-field perturbations and recorded their corrective responses as well as the after-effects exhibited during the subsequent unperturbed movement. In addition to the force perturbation, we artificially decreased or increased visual errors by multiplying hand deviations by a gain smaller or larger than one. Corrective responses to the force perturbation clearly scaled with the size of the visual error, but this scaling did not transfer one-to-one to motor adaptation and we observed no consistent interaction between limb and visual errors on adaptation. However, reducing visual errors during perturbation led to a small reduction of after-effects and this residual influence of visual feedback was eliminated when we instructed participants to control their hidden hand instead of the visual hand cursor. Taken together, our results demonstrate that task instructions and the need to correct for errors during perturbation are important factors to consider if we want to understand how the sensorimotor system uses and combines multimodal error signals to adapt movements.

Intervention Based on Psychomotor Rehabilitation in Children with Autism Spectrum Disorder ASD: Effect on Postural Control and Sensory Integration

Postural stability and control are essential motor skills for successfully performing various activities of daily living. However, children with autism spectrum disorder (ASD) exhibit significant sensorimotor impairments. The aim of this study was to investigate the efficacy of psychomotricity training on postural control (PC) of children with ASD. We recruited thirty children (age = 8.01 ± 1.2; weight = 31.66 ± 8.1 kg; height = 129.7 ± 10.8 cm) diagnosed with ASD (intellectual quotient > 50) to participate in this study. They were divided into two groups: the experimental group (n = 16) and control group (n = 14). Children in the experimental group were trained with psychomotor activities two times a week for nine weeks. Statistic postural balance was assessed before and after intervention and on different vision conditions. The results showed that the psychomotor training significantly improved PC in standing position under different conditions when compared to the control group, in all parameters (CoPA; CoPLX; CoPLy) (p < 0.01). Our preliminary findings suggest the usefulness of the psychomotor training in children with ASD on static PC.

The dorsal lateral geniculate nucleus and the pulvinar as essential partners for visual cortical functions

In most neuroscience textbooks, the thalamus is presented as a structure that relays sensory signals from visual, auditory, somatosensory, and gustatory receptors to the cerebral cortex. But the function of the thalamic nuclei goes beyond the simple transfer of information. This is especially true for the second-order nuclei, but also applies to first-order nuclei. First order thalamic nuclei receive information from the periphery, like the dorsal lateral geniculate nucleus (dLGN), which receives a direct input from the retina. In contrast, second order thalamic nuclei, like the pulvinar, receive minor or no input from the periphery, with the bulk of their input derived from cortical areas. The dLGN refines the information received from the retina by temporal decorrelation, thereby transmitting the most "relevant" signals to the visual cortex. The pulvinar is closely linked to virtually all visual cortical areas, and there is growing evidence that it is necessary for normal cortical processing and for aspects of visual cognition. In this article, we will discuss what we know and do not know about these structures and propose some thoughts based on the knowledge gained during the course of our careers. We hope that these thoughts will arouse curiosity about the visual thalamus and its important role, especially for the next generation of neuroscientists.

ROM1 is redundant to PRPH2 as a molecular building block of photoreceptor disc rims

Visual signal transduction takes place within a stack of flattened membranous "discs" enclosed within the light-sensitive photoreceptor outer segment. The highly curved rims of these discs, formed in the process of disc enclosure, are fortified by large hetero-oligomeric complexes of two homologous tetraspanin proteins, PRPH2 (a.k.a. peripherin-2 or rds) and ROM1. While mutations in PRPH2 affect the formation of disc rims, the role of ROM1 remains poorly understood. In this study, we found that the knockout of ROM1 causes a compensatory increase in the disc content of PRPH2. Despite this increase, discs of ROM1 knockout mice displayed a delay in disc enclosure associated with a large diameter and lack of incisures in mature discs. Strikingly, further increasing the level of PRPH2 rescued these morphological defects. We next showed that disc rims are still formed in a knockin mouse in which the tetraspanin body of PRPH2 was replaced with that of ROM1. Together, these results demonstrate that, despite its contribution to the formation of disc rims, ROM1 can be replaced by an excess of PRPH2 for timely enclosure of newly forming discs and establishing normal outer segment structure.

Rapid RGR-dependent visual pigment recycling is mediated by the RPE and specialized Müller glia

In daylight, demand for visual chromophore (11-cis-retinal) exceeds supply by the classical visual cycle. This shortfall is compensated, in part, by the retinal G-protein-coupled receptor (RGR) photoisomerase, which is expressed in both the retinal pigment epithelium (RPE) and in Müller cells. The relative contributions of these two cellular pools of RGR to the maintenance of photoreceptor light responses are not known. Here, we use a cell-specific gene reactivation approach to elucidate the kinetics of RGR-mediated recovery of photoreceptor responses following light exposure. Electroretinographic measurements in mice with RGR expression limited to either cell type reveal that the RPE and a specialized subset of Müller glia contribute both to scotopic and photopic function. We demonstrate that 11-cis-retinal formed through photoisomerization is rapidly hydrolyzed, consistent with its role in a rapid visual pigment regeneration process. Our study shows that RGR provides a pan-retinal sink for all-trans-retinal released under sustained light conditions and supports rapid chromophore regeneration through the photic visual cycle.

Pou3f1 orchestrates a gene regulatory network controlling contralateral retinogeniculate projections

The balance of contralateral and ipsilateral retinogeniculate projections is critical for binocular vision, but the transcriptional programs regulating this process remain ill defined. Here we show that the Pou class homeobox protein POU3F1 is expressed in nascent mouse contralateral retinal ganglion cells (cRGCs) but not ipsilateral RGCs (iRGCs). Upon Pou3f1 inactivation, the proportion of cRGCs is reduced in favor of iRGCs, leading to abnormal projection ratios at the optic chiasm. Conversely, misexpression of Pou3f1 in progenitors increases the production of cRGCs. Using CUT&RUN and RNA sequencing in gain- and loss-of-function assays, we demonstrate that POU3F1 regulates expression of several key members of the cRGC gene regulatory network. Finally, we report that POU3F1 is sufficient to induce RGC-like cell production, even in late-stage retinal progenitors of Atoh7 knockout mice. This work uncovers POU3F1 as a regulator of the cRGC transcriptional program, opening possibilities for optic nerve regenerative therapies.

Studies of Vision in Cricket-A Narrative Review

Vision is thought to play a substantial role in hitting and fielding in cricket. An understanding of which visual skills contribute during cricket play could inform future clinical training trials. This paper reviews what has been reported thus far regarding the relationship of visual skills to cricket performance and reviews the results of clinical trials in which the impact of visual skills training on cricket performance has been addressed. Fundamental or low-level visual skills, with the exception of color vision and perhaps near stereopsis and dynamic visual acuity, are similar between cricket players and the general population. Simple reaction time has been found to be shorter in cricket players in some but not all studies. While there is mixed or no evidence that the aforementioned visual skills are superior in cricket players compared to non-players, comparisons of eye and head movements and gaze tracking have revealed consistent differences between elite cricket batters and sub-elite batters. Future training studies could examine whether teaching sub-elite batters to emulate the gaze tracking patterns of elite batters is beneficial for batting. Lastly, clinical trials in which visual skills of cricket players have been trained have in many cases resulted in positive effects on visual skills, or judgments required in cricket, or cricket play. However, clinical trials with larger and more diverse groups of participants and correlations to on-field metrics and on-field performance (i.e., domain-specific assessments) are necessary before conclusions can be drawn regarding the efficacy of vision training.

The Value of VR-PVEP in Objective Evaluation of Monocular Refractive Visual Impairment

OBJECTIVES

To study the virtual reality-pattern visual evoked potential (VR-PVEP) P100 waveform characteristics of monocular visual impairment with different impaired degrees under simultaneous binocular perception and monocular stimulations.

METHODS

A total of 55 young volunteers with normal vision (using decimal recording method, far vision ≥0.8 and near vision ≥0.5) were selected to simulate three groups of monocular refractive visual impairment by interpolation method. The sum of near and far vision ≤0.2 was Group A, the severe visual impairment group; the sum of near and far vision <0.8 was Group B, the moderate visual impairment group; and the sum of near and far vision ≥0.8 was Group C, the mild visual impairment group. The volunteers' binocular normal visions were set as the control group. The VR-PVEP P100 peak times measured by simultaneous binocular perception and monocular stimulation were compared at four spatial frequencies 16×16, 24×24, 32×32 and 64×64.

RESULTS

In Group A, the differences between P100 peak times of simulant visual impairment eyes and simultaneous binocular perception at 24×24, 32×32 and 64×64 spatial frequencies were statistically significant (P<0.05); and the P100 peak time of normal vision eyes at 64×64 spatial frequency was significantly different from the simulant visual impairment eyes (P<0.05). In Group B, the differences between P100 peak times of simulant visual impairment eyes and simultaneous binocular perception at 16×16, 24×24 and 64×64 spatial frequencies were statistically significant (P<0.05); and the P100 peak time of normal vision eyes at 64×64 spatial frequency was significantly different from the simulant visual impairment eyes (P<0.05). In Group C, there was no significant difference between P100 peak times of simulant visual impairment eyes and simultaneous binocular perception at all spatial frequencies (P>0.05). There was no significant difference in the P100 peak times measured at all spatial frequencies between simulant visual impairment eyes and simultaneous binocular perception in the control group (P>0.05).

CONCLUSIONS

VR-PVEP can be used for visual acuity evaluation of patients with severe and moderate monocular visual impairment, which can reflect the visual impairment degree caused by ametropia. VR-PVEP has application value in the objective evaluation of visual function and forensic clinical identification.

Scalable Gaussian process inference of neural responses to natural images

Predicting the responses of sensory neurons is a long-standing neuroscience goal. However, while there has been much progress in modeling neural responses to simple and/or artificial stimuli, predicting responses to natural stimuli remains an ongoing challenge. On the one hand, deep neural networks perform very well on certain datasets but can fail when data are limited. On the other hand, Gaussian processes (GPs) perform well on limited data but are poor at predicting responses to high-dimensional stimuli, such as natural images. Here, we show how structured priors, e.g., for local and smooth receptive fields, can be used to scale up GPs to model neural responses to high-dimensional stimuli. With this addition, GPs largely outperform a deep neural network trained to predict retinal responses to natural images, with the largest differences observed when both models are trained on a small dataset. Further, since they allow us to quantify the uncertainty in their predictions, GPs are well suited to closed-loop experiments, where stimuli are chosen actively so as to collect "informative" neural data. We show how GPs can be used to actively select which stimuli to present, so as to i) efficiently learn a model of retinal responses to natural images, using few data, and ii) rapidly distinguish between competing models (e.g., a linear vs. a nonlinear model). In the future, our approach could be applied to other sensory areas, beyond the retina.

A review of experimental task design in psychophysical eye tracking research

While eye tracking is a technique commonly used in the experimental study of higher-level perceptual processes such as visual search, working memory, reading, and scene exploration, its use for the quantification of basic visual functions (visual acuity, contrast sensitivity, color vision, motion detection) is less explored. The use of eye movement features as dependent variables in a psychophysical investigation can serve multiple roles. They can be central in studies with neurological patients or infants that cannot comply with verbal instructions, understand task demands, and/or emit manual responses. The technique may also serve a complementary role, determining the conditions under which a manual or verbal response is given, such as stimulus position in the visual field, or it can afford the analysis of new dependent variables, such as the time interval between oculomotor and manual responses. Our objective is to review the literature that applied the eye tracking technique to psychophysical problems. The two questions our review raises are: can eye movements (reflex or voluntary) be an objective index of stimulus detection in psychophysical tasks? If so, under what conditions, and how does it compare with traditional paradigms requiring manual responses? Our (non-systematic) methodological review selected studies that used video-oculography as the technique of choice and had a basic visual function as their primary object of investigation. Studies satisfying those criteria were then categorized into four broad classes reflecting their main research interest: (1) stimulus detection and threshold estimation, (2) the effects of stimulus properties on fixational eye movements, (3) the effects of eye movements on perception, and (4) visual field assessment. The reviewed studies support the idea that eye tracking is a valuable technique for the study of basic perceptual processes. We discuss methodological characteristics within each of the proposed classification area, with the objective of informing future task design.

The perceptual consequences and neurophysiology of eye blinks

A hand passing in front of a camera produces a large and obvious disruption of a video. Yet the closure of the eyelid during a blink, which lasts for hundreds of milliseconds and occurs thousands of times per day, typically goes unnoticed. What are the neural mechanisms that mediate our uninterrupted visual experience despite frequent occlusion of the eyes? Here, we review the existing literature on the neurophysiology, perceptual consequences, and behavioral dynamics of blinks. We begin by detailing the kinematics of the eyelid that define a blink. We next discuss the ways in which blinks alter visual function by occluding the pupil, decreasing visual sensitivity, and moving the eyes. Then, to anchor our understanding, we review the similarities between blinks and other actions that lead to reductions in visual sensitivity, such as saccadic eye movements. The similarity between these two actions has led to suggestions that they share a common neural substrate. We consider the extent of overlap in their neural circuits and go on to explain how recent findings regarding saccade suppression cast doubt on the strong version of the shared mechanism hypothesis. We also evaluate alternative explanations of how blink-related processes modulate neural activity to maintain visual stability: a reverberating corticothalamic loop to maintain information in the face of lid closure; and a suppression of visual transients related to lid closure. Next, we survey the many areas throughout the brain that contribute to the execution of, regulation of, or response to blinks. Regardless of the underlying mechanisms, blinks drastically attenuate our visual abilities, yet these perturbations fail to reach awareness. We conclude by outlining opportunities for future work to better understand how the brain maintains visual perception in the face of eye blinks. Future work will likely benefit from incorporating theories of perceptual stability, neurophysiology, and novel behavior paradigms to address issues central to our understanding of natural visual behavior and for the clinical rehabilitation of active vision.

Variability of visual field maps in human early extrastriate cortex challenges the canonical model of organization of V2 and V3

Visual field maps in human early extrastriate areas (V2 and V3) are traditionally thought to form mirror-image representations which surround the primary visual cortex (V1). According to this scheme, V2 and V3 form nearly symmetrical halves with respect to the calcarine sulcus, with the dorsal halves representing lower contralateral quadrants, and the ventral halves representing upper contralateral quadrants. This arrangement is considered to be consistent across individuals, and thus predictable with reasonable accuracy using templates. However, data that deviate from this expected pattern have been observed, but mainly treated as artifactual. Here, we systematically investigate individual variability in the visual field maps of human early visual cortex using the 7T Human Connectome Project (HCP) retinotopy dataset. Our results demonstrate substantial and principled inter-individual variability. Visual field representation in the dorsal portions of V2 and V3 was more variable than in their ventral counterparts, including substantial departures from the expected mirror-symmetrical patterns. In addition, left hemisphere retinotopic maps were more variable than those in the right hemisphere. Surprisingly, only one-third of individuals had maps that conformed to the expected pattern in the left hemisphere. Visual field sign analysis further revealed that in many individuals the area conventionally identified as dorsal V3 shows a discontinuity in the mirror-image representation of the retina, associated with a Y-shaped lower vertical representation. Our findings challenge the current view that inter-individual variability in early extrastriate cortex is negligible, and that the dorsal portions of V2 and V3 are roughly mirror images of their ventral counterparts.

Comparison of Fine Structure of the Compound Eyes in Eucryptorrhynchus scrobiculatus and Eucryptorrhynchus brandti Adults

Eucryptorrhynchus scrobiculatus and E. brandti are the main borers of Ailanthus altissima, causing serious economic and ecological losses. The external morphology and internal ultrastructure of the compound eyes of two related weevils were investigated with light microscopy, scanning electron microscopy, and transmission electron microscopy. E. scrobiculatus and E. brandti possess a pair of reniform apposition compound eyes and contain about 550 ommatidia per eye. The interommatidial angle of E. scrobiculatus and E. brandti are 7.08 ± 0.31° and 4.84 ± 0.49°, respectively. The corneal thickness, rhabdom length, and ommatidium length of E. scrobiculatus are significantly greater than those of E. brandti. Under light-adapted conditions, the pigment granules are mainly distributed at the junction of the cone and the rhabdom, and the diameter and the cross-sectional area of the middle end of the rhabdom is increased in the two weevil species. Under dark-adapted conditions, the pigment granules shift longitudinally and are evenly distributed on both sides of the cone and the rhabdom, and the diameter and cross-sectional area of the middle end of the rhabdom are decreased. The discrepancy in visual structure is beneficial for adaptation to niche differentiation of the two related species. The present results suggest that the two weevils possess different visual organ structures to perceive visual information in the external environment.

The Burden of Pediatric Visual Impairment and Ocular Diagnoses in Barbados

Visual impairment (VI) negatively affects a child's quality of life. The prevalence of VI in the Caribbean is nearly three times higher than in the United States, but the causes remain uncertain. This study leverages Barbados' unique eye care system to survey the eye diseases and VI prevalence in Barbadian children. Medical records of all patients aged <19 years who received ophthalmic care in Barbados' two public eye care centers between January and December 2019 were reviewed, capturing the entirety of public pediatric eye care within the study period. Age at the first visit to the clinic and at the final visit in 2019, sex, best-corrected visual acuity (BCVA), past medical history, and clinical diagnoses were extracted and analyzed. VI was defined as a BCVA of 6/12 or worse in the better-seeing eye. There were 3278 patient records with a mean age at the first visit of 7.8 ± 3.9 years. There were 80 (2.4%) children with VI, 62.5% of which were attributed to amblyopia. A total of 94% of VI was preventable or treatable. The most common diagnoses were refractive error (87.5%), strabismus (27.5%), and allergic eye disease (20.0%). Amblyopia is the major cause of pediatric VI in Barbados and is largely avoidable.

Vision-related quality of life among patients with keratoconus: a cross sectional study

Purpose

The present study aimed to evaluate the quality of life of keratoconus patients residing in Nablus city, Palestine. Furthermore, we investigated the possible correlation between Pentacam topographic indices and the quality of life of patients with keratoconus.

Methods

This cross-sectional study evaluated keratoconus patients at An-Najah University Hospital in 2019, diagnosed through clinical examination and corneal tomography. A control group was randomly selected from non-keratoconus patients with normal tomography. The NEI-VFQ-25 questionnaire was administered during face-to-face interviews to compare both groups. NEI-VFQ-25 assesses vision-related quality of life and is a validated tool.

Results

Keratoconus patients' quality of life is significantly impacted, mainly in near and distant vision, general vision, mental health, and social health, but not in general health, ocular pain, color vision, role difficulties, or dependency. Visual acuity is significantly affected in both eyes of keratoconus patients.

Conclusion

Patients with keratoconus exhibit a decreased quality of life related to vision, with physical, emotional, and social impairments demonstrated by the NEI-VFQ-25 when compared to controls. Since keratoconus patients are typically young adults in their productive years, understanding their concerns about their future is an important public health aspect that can aid in modifying their treatments. By addressing the specific needs of this patient population, healthcare providers can better support their long-term well-being and quality of life.

Object representation in a gravitational reference frame

When your head tilts laterally, as in sports, reaching, and resting, your eyes counterrotate less than 20%, and thus eye images rotate, over a total range of about 180°. Yet, the world appears stable and vision remains normal. We discovered a neural strategy for rotational stability in anterior inferotemporal cortex (IT), the final stage of object vision in primates. We measured object orientation tuning of IT neurons in macaque monkeys tilted +25 and -25° laterally, producing ~40° difference in retinal image orientation. Among IT neurons with consistent object orientation tuning, 63% remained stable with respect to gravity across tilts. Gravitational tuning depended on vestibular/somatosensory but also visual cues, consistent with previous evidence that IT processes scene cues for gravity's orientation. In addition to stability across image rotations, an internal gravitational reference frame is important for physical understanding of a world where object position, posture, structure, shape, movement, and behavior interact critically with gravity.

The interaction between instrumental activities of daily living and dual sensory function on cognition among the elderly in China: A cross-sectional survey

To explore the interaction of instrumental activities of daily living (IADLs) and dual sensory function on cognition in the elderly. A cross-sectional survey was conducted in six general hospitals in China, from October 2022 to December 2022. Data collection included general information, IADLs scale, self-reported sensory function questionnaire, and mini-mental state examination (MMSE). Binary logistic regression was used to examine the association between factors and cognition. The interactive effect was evaluated by synergy index (S), relative excess risk due to interaction (RERI), and attributable proportion due to interaction (AP). The odds ratio (OR) of IADLs decline in cognition is 4.412 (95% confidence interval [CI]: 3.633-5.358, p < 0.001); the OR of dual sensory difficulty on cognition is 2.502 (95% CI: 1.272-4.921, p = 0.008). The OR of interaction between IADLs decline and dual sensory difficulty on cognition is 13.737 (95% CI: 9.726-19.400, p < 0.001). RERI (95% CI) = 7.823 (3.230-12.417), AP (95% CI) = 0.570 (0.392-0.747), S (95% CI) = 2.593 (1.616-4.160). IADLs decline and dual sensory difficulty are associated with cognitive decline. IADLs decline and dual sensory difficulty have interaction with cognitive decline; the interaction is greater than the sum effect of those two on cognitive decline independently. Sensory and IADLs assessment can be used as early screening items for cognition among the elderly. In addition, protecting sensory function and maintaining IADLs in the elderly can help protect their cognition.

Absolute Quantification of Photoreceptor Outer Segment Proteins

Photoreceptor cells generate neuronal signals in response to capturing light. This process, called phototransduction, takes place in a highly specialized outer segment organelle. There are significant discrepancies in the reported amounts of many proteins supporting this process, particularly those of low abundance, which limits our understanding of their molecular organization and function. In this study, we used quantitative mass spectrometry to simultaneously determine the abundances of 20 key structural and functional proteins residing in mouse rod outer segments. We computed the absolute number of molecules of each protein residing within an individual outer segment and the molar ratio among all 20 proteins. The molar ratios of proteins comprising three well-characterized constitutive complexes in outer segments differed from the established subunit stoichiometries of these complexes by less than 7%, highlighting the exceptional precision of our quantification. Overall, this study resolves multiple existing discrepancies regarding the outer segment abundances of these proteins, thereby advancing our understanding of how the phototransduction pathway functions as a single, well-coordinated molecular ensemble.

Flexible structure learning under uncertainty

Experience is known to facilitate our ability to interpret sequences of events and make predictions about the future by extracting temporal regularities in our environments. Here, we ask whether uncertainty in dynamic environments affects our ability to learn predictive structures. We exposed participants to sequences of symbols determined by first-order Markov models and asked them to indicate which symbol they expected to follow each sequence. We introduced uncertainty in this prediction task by manipulating the: (a) probability of symbol co-occurrence, (b) stimulus presentation rate. Further, we manipulated feedback, as it is known to play a key role in resolving uncertainty. Our results demonstrate that increasing the similarity in the probabilities of symbol co-occurrence impaired performance on the prediction task. In contrast, increasing uncertainty in stimulus presentation rate by introducing temporal jitter resulted in participants adopting a strategy closer to probability maximization than matching and improving in the prediction tasks. Next, we show that feedback plays a key role in learning predictive statistics. Trial-by-trial feedback yielded stronger improvement than block feedback or no feedback; that is, participants adopted a strategy closer to probability maximization and showed stronger improvement when trained with trial-by-trial feedback. Further, correlating individual strategy with learning performance showed better performance in structure learning for observers who adopted a strategy closer to maximization. Our results indicate that executive cognitive functions (i.e., selective attention) may account for this individual variability in strategy and structure learning ability. Taken together, our results provide evidence for flexible structure learning; individuals adapt their decision strategy closer to probability maximization, reducing uncertainty in temporal sequences and improving their ability to learn predictive statistics in variable environments.

Camouflage using three-dimensional surface disruption

Disruptive markings are common in animal patterns and can provide camouflage benefits by concealing the body's true edges and/or by breaking the surface of the body into multiple depth planes. Disruptive patterns that are accentuated by high contrast borders are most likely to provide false depth cues to enhance camouflage, but studies to date have used visual detection models or humans as predators. We presented three-dimensional-printed moth-like targets to wild bird predators to determine whether: (1) three-dimensional prey with disrupted body surfaces have higher survival than three-dimensional prey with continuous surfaces, (2) two-dimensional prey with disruptive patterns or enhanced edge markings have higher survival than non-patterned two-dimensional prey. We found a survival benefit for three-dimensional prey with disrupted surfaces, and a significant effect of mean wing luminance. There was no evidence that false depth cues provided the same protective benefits as physical surface disruption in three-dimensional prey, perhaps because our treatments did not mimic the complexity of patterns found in natural animal markings. Our findings indicate that disruption of surface continuity is an important strategy for concealing a three-dimensional body shape.

Abnormal foveal morphology in carriers of oculocutaneous albinism

BACKGROUND/AIMS

To investigate the foveal morphology in carriers of oculocutaneous albinism (OCA) using spectral domain optical coherence tomography (SD-OCT). A cross-sectional, observational study.

METHODS

Handheld SD-OCT (Envisu C2300) was used to acquire horizontal scans through the centre of the fovea in biological parents of patients with OCA (n=28; mean age±SD=40.43±8.07 years) and age-matched and ethnicity-matched controls (n=28; mean age±SD=38.04±10.27 years). Sequence analysis was performed for variants in known genes associated with OCA. Best-corrected visual acuity (BCVA), presence of foveal hypoplasia and grade, foveal, parafoveal and perifoveal thickness measurements of total retinal layers (TRL), inner retinal layers (IRL) and outer retinal layers (ORL) thickness were measured.

RESULTS

Foveal hypoplasia was identified in 32.14% of OCA carriers; grade 1 in all cases. OCA carriers demonstrated significant thicker TRL thickness (median difference: 13.46 µm, p=0.009) and IRL thickness (mean difference: 8.98 µm, p<0.001) at the central fovea compared with controls. BCVA of carriers was between -0.16 and 0.18 logMAR (mean: 0.0 logMAR). No significant differences in BCVA was noted between OCA carriers or controls (p=0.83). In the OCA carriers, we identified previously reported pathogenic variants in TYR, OCA2 and SLC45A2, novel OCA2 variants (n=3) and heterozygosity of the pathogenic TYR haplotype.

CONCLUSION

We have, for the first time, identified foveal abnormalities in OCA carriers. This provides clinical value, particularly in cases where limited phenotype data are available. Our findings raise the possibility that previously reported mild cases of foveal hypoplasia or isolated foveal hypoplasia could correspond to OCA carrier status.

Guidelines of the International Headache Society for Controlled Clinical Trials in Idiopathic Intracranial Hypertension

The quality of clinical trials is essential to advance treatment, inform regulatory decisions and meta-analysis. With the increased incidence of idiopathic intracranial hypertension and the emergence of clinical trials for novel therapies in this condition, the International Headache Society Guidelines for Controlled Clinical Trials in Idiopathic Intracranial Hypertension aims to establish guidelines for designing state-of-the-art controlled clinical trials for idiopathic intracranial hypertension.

The art of the float

For more than 2000 years, artists have exploited cast shadows to influence how objects appear to be positioned in a scene. A contact cast shadow can anchor an object to the ground and a detached cast shadow can make an object appear to float. However, there is a period of approximately 1000 years when there were virtually no cast shadows in art. How were states of contact versus floating depicted by artists without cast shadows? Here, we survey various techniques used by artists to anchor relative position with and without cast shadows. We then conduct experimental tests of the hypothesized surface attraction principles that underlie these techniques. In the absence of cast shadows, an object (a wooden box) was often seen as resting on a surface as long as that surface offered information about ground orientation and support (a tiled floor). When the ground surface was ambiguous and cloud-like (1/f noise), the box was more likely to be seen to float. The presence of cast shadows made the box appear to contact the ground whether it was well-defined or ambiguous. Both shadows and surface support also increased the accuracy with which participants detected when the box was tilted up from the ground. These results indicate that artists long ago discovered the important power of support relationships to anchor objects to surfaces in the absence of shadows.

Impaired Direction Selectivity in the Nucleus of the Optic Tract of Albino Mice

Purpose

Human albinos have a low visual acuity. This is partially due to the presence of spontaneous erroneous eye movements called pendular nystagmus. This nystagmus is present in other albino vertebrates and has been hypothesized to be caused by aberrant wiring of retinal ganglion axons to the nucleus of the optic tract (NOT), a part of the accessory optic system involved in the optokinetic response to visual motion. The NOT in pigmented rodents is preferentially responsive to ipsiversive motion (i.e., motion in the contralateral visual field in the temporonasal direction). We compared the response to visual motion in the NOT of albino and pigmented mice to understand if motion coding and preference are impaired in the NOT of albino mice.

Methods

We recorded neuronal spiking activity with Neuropixels probes in the visual cortex and NOT in C57BL/6JRj mice (pigmented) and DBA/1JRj mice with oculocutaneous albinism (albino).

Results

We found that in pigmented mice, NOT is retinotopically organized, and neurons are direction tuned, whereas in albino mice, neuronal tuning is severely impaired. Neurons in the NOT of albino mice do not have a preference for ipsiversive movement. In contrast, neuronal tuning in visual cortex was preserved in albino mice and did not differ significantly from the tuning in pigmented mice.

Conclusions

We propose that excessive interhemispheric crossing of retinal projections in albinos may cause the disrupted left/right direction encoding we found in NOT. This, in turn, impairs the normal horizontal optokinetic reflex and leads to pendular albino nystagmus.

Asymptomatic idiopathic intracranial hypertension: Prevalence and prognosis

BACKGROUND

Little is known about the presentation and prognosis of asymptomatic idiopathic intracranial hypertension (IIH). Papilloedema can be found incidentally on routine fundus examination, with many of these patients actually having symptoms on direct questioning. The aim was to evaluate visual and headache outcomes in people with IIH who present with or without symptoms.

METHODS

Prospective observational cohort study, between 2012 and 2021, 343 people with confirmed IIH diagnosis were enrolled in the IIH:Life database. Outcomes such as vision (LogMAR); Humphrey visual field perimetric mean deviation (PMD) and optical coherence tomography (OCT) and headache were evaluated using LOESS (locally weighted scatterplot smoothing) graphs and regression analysis.

RESULTS

One hundred and twenty-one people had incidentally found papilloedema, with 36 people with completely asymptomatic presentations. Those with asymptomatic IIH at diagnosis had similar visual prognosis compared to those with symptomatic disease. Sixty-six percent of the asymptomatic cohort became symptomatic during follow-up, and of these the predominant symptom was headache (96%). Headache frequency during follow-up was lower in the asymptomatic cohort.

CONCLUSIONS

The prognosis of those with IIH who present with or without symptoms is similar.

Embracing deepfakes and AI-generated images in neuroscience research

The rise of deepfakes and AI-generated images has raised concerns regarding their potential misuse. However, this commentary highlights the valuable opportunities these technologies offer for neuroscience research. Deepfakes deliver accessible, realistic and customisable dynamic face stimuli, while generative adversarial networks (GANs) can generate and modify diverse and high-quality static content. These advancements can enhance the variability and ecological validity of research methods and enable the creation of previously unattainable stimuli. When AI-generated images are informed by brain responses, they provide unique insights into the structure and function of visual systems. The authors argue that experimental psychologists and cognitive neuroscientists stay informed about these emerging tools and embrace their potential to advance the field of visual neuroscience.

Vision outcomes in children with fetal alcohol spectrum disorders

BACKGROUND

Previous studies demonstrated that children with Fetal Alcohol Spectrum Disorders (FASD) are more likely to have vision impairments. However, existing human clinical and epidemiological investigations are few and include limited sample sizes. This study aimed to explore the association between ophthalmologic abnormalities and FASD in a sample of 5-7 year old children in the general population.

METHODS

This was a cross-sectional study nested in a larger study intended to estimate the prevalence of FASD in San Diego, California, conducted between 2012 and 2014. Prenatal exposure to alcohol, dysmorphology examinations, and a neurobehavioral testing battery were collected for each child and an FASD diagnosis was assigned. Parents of participating children were asked to release their child's vision screening or diagnostic records.

RESULTS

Vision records were obtained for 424 participants in the larger prevalence study. Of these, 53 children were classified as having FASD. A statistically significant association was found between FASD and a diagnosis of strabismus; 5/42 (11.9%) of children who were classified as having FASD had strabismus compared to 6/290 (2.1%) of children who were not classified as having FASD (p = .01). All five cases of strabismus in the FASD group occurred in 19 children classified as having partial fetal alcohol syndrome (pFAS). No association was found between FASD and vision impairment (p = .23), refractive errors (p = .66), glasses/contact lens prescription (p = .30), or having one or more ophthalmological abnormalities (p = .97).

CONCLUSIONS

An association between strabismus and FASD, specifically partial FAS, suggests that the effect of alcohol exposure on risk of strabismus must be severe enough to result in facial features consistent with FASD. This emphasizes the importance of vision screening in children with FASD.

The multi-level regulation of clownfish metamorphosis by thyroid hormones

Most marine organisms have a biphasic life cycle during which pelagic larvae transform into radically different juveniles. In vertebrates, the role of thyroid hormones (THs) in triggering this transition is well known, but how the morphological and physiological changes are integrated in a coherent way with the ecological transition remains poorly explored. To gain insight into this question, we performed an integrated analysis of metamorphosis of a marine teleost, the false clownfish (Amphiprion ocellaris). We show how THs coordinate a change in color vision as well as a major metabolic shift in energy production, highlighting how it orchestrates this transformation. By manipulating the activity of liver X regulator (LXR), a major regulator of metabolism, we also identify a tight link between metabolic changes and metamorphosis progression. Strikingly, we observed that these regulations are at play in the wild, explaining how hormones coordinate energy needs with available resources during the life cycle.

Burden of blindness and vision loss in China over the past 30 years: findings and predictions based on the Global Burden of Disease Study 2019

AIMS

To investigate the burden of blindness and vision loss (BVL) in China over the past 30 years according to year, age and sex, and to estimate future predictions.

METHODS

We analysed the years lived with disability (YLDs), number of cases, age-standardised YLD rates (ASYRs) and age-standardised prevalence rates (ASPRs) of BVL in China from 1990 to 2019. We focused on changes over time using estimated annual percentage changes (EAPCs). Additionally, we used the Bayesian age-period-cohort model to predict the BVL burden from 2020 to 2030.

RESULTS

The number of YLDs and prevalent cases due to BVL increased from 2.57 (95% uncertainty interval (UI) 1.74 to 3.72) and 90.76 million (95% UI 72.21 to 111.92) in 1990 to 5.42 (95% UI 3.61 to 8.02) and 211.67 million (95% UI 168.21 to 259.66) in 2019, respectively. The BVL ASYRs and ASPRs showed a decreasing trend, with EAPCs of -0.13 (95% CI -0.28 to 0.02) and -0.11 (95% CI -0.19 to -0.04), respectively. The elderly and female populations had a higher BVL burden. The numbers of YLDs and cases due to BVL are projected to continue rising to 7.74 and 279.49 million in 2030, respectively. The ASYRs and ASPRs also showed increasing trends.

CONCLUSION

While rates of BVL in China have decreased, there has been a notable increase in the number of YLDs and new cases over the past 30 years. Projections suggest that the burden of BVL will continue to rise over the next 11 years. To address this challenge, appropriate policies must be implemented.