An edge-simplicity bias in the visual input to young infants.

The development of sparse edge coding in the mammalian visual cortex depends on early visual experience. In humans, there are multiple indicators that the statistics of early visual experiences has unique properties that may support these developments. However, there are no direct measures of the edge statistics of infant daily-life experience. Using head-mounted cameras to capture egocentric images of young infants and adults in the home, we found infant images to have distinct edge statistics relative to adults. For infants, scenes with sparse edge patterns-few edges and few orientations-dominate. The findings implicate biased early input at the scale of daily life that is likely specific to the early months after birth and provide insights into the quality, amount, and timing of the visual experiences during the foundational developmental period for human vision.

Primacy of vision shapes behavioral strategies and neural substrates of spatial navigation in marmoset hippocampus.

The role of the hippocampus in spatial navigation has been primarily studied in nocturnal mammals, such as rats, that lack many adaptations for daylight vision. Here we demonstrate that during 3D navigation, the common marmoset, a new world primate adapted to daylight, predominantly uses rapid head-gaze shifts for visual exploration while remaining stationary. During active locomotion marmosets stabilize the head, in contrast to rats that use low-velocity head movements to scan the environment as they locomote. Pyramidal neurons in the marmoset hippocampus CA3/CA1 regions predominantly show mixed selectivity for 3D spatial view, head direction, and place. Exclusive place selectivity is scarce. Inhibitory interneurons are predominantly mixed selective for angular head velocity and translation speed. Finally, we found theta phase resetting of local field potential oscillations triggered by head-gaze shifts. Our findings indicate that marmosets adapted to their daylight ecological niche by modifying exploration/navigation strategies and their corresponding hippocampal specializations.

Tactile adaptation to orientation produces a robust tilt aftereffect and exhibits crossmodal transfer when tested in vision.

Orientation processing is one of the most fundamental functions in both visual and somatosensory perception. Converging findings suggest that orientation processing in both modalities is closely linked: somatosensory neurons share a similar orientation organisation as visual neurons, and the visual cortex has been found to be heavily involved in tactile orientation perception. Hence, we hypothesized that somatosensation would exhibit a similar orientation adaptation effect, and this adaptation effect would be transferable between the two modalities, considering the above-mentioned connection. The tilt aftereffect (TAE) is a demonstration of orientation adaptation and is used widely in behavioural experiments to investigate orientation mechanisms in vision. By testing the classic TAE paradigm in both tactile and crossmodal orientation tasks between vision and touch, we were able to show that tactile perception of orientation shows a very robust TAE, similar to its visual counterpart. We further show that orientation adaptation in touch transfers to produce a TAE when tested in vision, but not vice versa. Additionally, when examining the test sequence following adaptation for serial effects, we observed another asymmetry between the two conditions where the visual test sequence displayed a repulsive intramodal serial dependence effect while the tactile test sequence exhibited an attractive serial dependence. These findings provide concrete evidence that vision and touch engage a similar orientation processing mechanism. However, the asymmetry in the crossmodal transfer of TAE and serial dependence points to a non-reciprocal connection between the two modalities, providing further insights into the underlying processing mechanism.

Influence of lighting on visual performance.

PURPOSE: This review emphasizes the effect of light on visual efficiency, the impact of different lighting focuses, types of lighting, and their influence on vision and productivity. Light sources and standards are intriguing subjects for ophthalmologists. Guidelines regarding the level of lighting influence on visual activities can enhance visual performance.Methods: This article was developed based on literature reviews, with a bibliographic survey conducted in databases such as PubMed, MEDLINE, Web of Science, Embase, LILACS, and SciELO. RESULTS: Provides recommendations for understanding information regarding the influence of lighting on visual performance. CONCLUSION: Proper workplace lighting is crucial for improving visual efficiency, safety, productivity, and worker health. Efficient workplace lighting should avoid light sources directed towards the worker's face, prevent harmful glare, be more intense in the work area, and uniform in the rest of the room. Ophthalmologists should be knowledgeable about and provide guidance on correct lighting to ensure patient comfort and satisfaction with visual correction.

Looking across the gap: Understanding the evolution of eyes and vision among insects.

The compound eyes of insects exhibit stunning variation in size, structure, and function, which has allowed these animals to use their vision to adapt to a huge range of different environments and lifestyles, and evolve complex behaviors. Much of our knowledge of eye development has been learned from Drosophila, while visual adaptations and behaviors are often more striking and better understood from studies of other insects. However, recent studies in Drosophila and other insects, including bees, beetles, and butterflies, have begun to address this gap by revealing the genetic and developmental bases of differences in eye morphology and key new aspects of compound eye structure and function. Furthermore, technical advances have facilitated the generation of high-resolution connectomic data from different insect species that enhances our understanding of visual information processing, and the impact of changes in these processes on the evolution of vision and behavior. Here, we review these recent breakthroughs and propose that future integrated research from the development to function of visual systems within and among insect species represents a great opportunity to understand the remarkable diversification of insect eyes and vision.

Research progress on insect visual electrophysiological techniques.

Insect visual electrophysiological techniques are important to study the electrical characteristics of photoreceptor cells and visual neurons in insects, including electroretinography (ERG) and microelectrode intracellular recording (MIR). ERG records the changes of voltage or electric current in the retina of insects in response to different light stimuli, which occurs outside the cell. MIR records the changes in individual photoreceptor cells or visual neurons of an insect exposed to different lights, which occurs inside the cell. Insect visual electrophysiological techniques can explore the mechanism of electrophysiological response of insects' vision to light and reveal their sensitive light spectra and photoreceptor types. This review introduced the basic structure and the principle of ERG and MIR, and summarized their applications in insect researches in the past 20 years, which would provide references for elucidating the mechanism of light perception in insects and the use of insect phototropism to control pests.

Collective behaviors of animal groups may stem from visual lateralization-Tending to obtain information through one eye.

Animal groups exhibit various captivating movement patterns, which manifest as intricate interactions among group members. Several models have been proposed to elucidate collective behaviors in animal groups. These models achieve a certain degree of efficacy; however, inconsistent experimental findings suggest insufficient accuracy. Experiments have shown that some organisms employ a single information channel and visual lateralization to glean knowledge from other individuals in collective movements. In this study, we consider individuals' visual lateralization and a single information channel and develop a self-propelled particle model to describe the collective behavior of large groups. The results suggest that homogeneous visual lateralization gives the group a strong sense of cohesiveness, thereby enabling diverse collective behaviors. As the overlapping field grows, the cohesiveness gradually dissipates. Inconsistent visual lateralization among group members can reduce the cohesiveness of the group, and when there is a high degree of heterogeneity in visual lateralization, the group loses their cohesiveness. This study also examines the influence of visual lateralization heterogeneity on specific formations, and the results indicate that the directional migration formation is responsive to such heterogeneity. We propose an information network to portray the transmission of information within groups, which explains the cohesiveness of groups and the sensitivity of the directional migration formation.

Does sleep quality affect balance? The perspective from the somatosensory, vestibular, and visual systems.

OBJECTIVE: Previous studies have focused on the balance system's involvement in sleep deprivation or disorders. This study investigated how daily routine sleep quality affects the balance system of people without sleep deprivation or diagnosed sleep disorders. METHODS: The study included 45 participants with a BMI score of <25. The PSQI was used to determine sleep quality. The SOT, HS-SOT, and ADT evaluated the vestibular system's functionality. RESULTS: In SOT, condition 3, 4, 5, and 6 composite scores, VIS and VEST composite balance scores, and HS-SOT 5 scores were lower in the HPSQI group. At the same time, there is a statistically significant negative correlation between these scores and PSQI scores. CONCLUSION: Poor sleep quality may be a factor influencing the balance system. Sleep quality affects the visual and vestibular systems rather than the somatosensory system. The population should be made aware of this issue, and clinicians should consider the potential impact of sleep quality when evaluating the balance system.

Monolithic 2D Perovskites Enabled Artificial Photonic Synapses for Neuromorphic Vision Sensors.

Neuromorphic visual sensors (NVS) based on photonic synapses hold a significant promise to emulate the human visual system. However, current photonic synapses rely on exquisite engineering of the complex heterogeneous interface to realize learning and memory functions, resulting in high fabrication cost, reduced reliability, high energy consumption and uncompact architecture, severely limiting the up-scaled manufacture, and on-chip integration. Here a photo-memory fundamental based on ion-exciton coupling is innovated to simplify synaptic structure and minimize energy consumption. Due to the intrinsic organic/inorganic interface within the crystal, the photodetector based on monolithic 2D perovskite exhibits a persistent photocurrent lasting about 90 s, enabling versatile synaptic functions. The electrical power consumption per synaptic event is estimated to be≈1.45 × 10-16 J, one order of magnitude lower than that in a natural biological system. Proof-of-concept image preprocessing using the neuromorphic vision sensors enabled by photonic synapse demonstrates 4 times enhancement of classification accuracy. Furthermore, getting rid of the artificial neural network, an expectation-based thresholding model is put forward to mimic the human visual system for facial recognition. This conceptual device unveils a new mechanism to simplify synaptic structure, promising the transformation of the NVS and fostering the emergence of next generation neural networks.

Functional benefits of cognitively driven pupil-size changes.

Pupil-size changes are typically associated with the pupil light response (PLR), where they are driven by the physical entry of light into the eye. However, pupil-size changes are also influenced by various cognitive processes, where they are driven by higher-level cognition. For example, the strength of the PLR is not solely affected by physical properties of the light but also by cognitive factors, such as whether the source of light is attended or not, which results in an increase or decrease in the strength of the PLR. Surprisingly, although cognitively driven pupil-size changes have been the focus of extensive research, their possible functions are rarely discussed. Here we consider the relative (dis)advantages of small versus large pupils in different situations from a theoretical point of view, and compare these to empirical results showing how pupil size actually changes in these situations. Based on this, we suggest that cognitively driven pupil-size changes optimize vision either through preparation, embodied representations, or a differential emphasis on central or peripheral vision. More generally, we argue that cognitively driven pupil-size changes are a form of sensory tuning: a subtle adjustment of the eyes to optimize vision for the current situation and the immediate future. This article is categorized under: Neuroscience > Cognition Neuroscience > Physiology Neuroscience > Behavior.

Evolution of neuronal cell classes and types in the vertebrate retina.

The basic plan of the retina is conserved across vertebrates, yet species differ profoundly in their visual needs1. Retinal cell types may have evolved to accommodate these varied needs, but this has not been systematically studied. Here we generated and integrated single-cell transcriptomic atlases of the retina from 17 species: humans, two non-human primates, four rodents, three ungulates, opossum, ferret, tree shrew, a bird, a reptile, a teleost fish and a lamprey. We found high molecular conservation of the six retinal cell classes (photoreceptors, horizontal cells, bipolar cells, amacrine cells, retinal ganglion cells (RGCs) and Müller glia), with transcriptomic variation across species related to evolutionary distance. Major subclasses were also conserved, whereas variation among cell types within classes or subclasses was more pronounced. However, an integrative analysis revealed that numerous cell types are shared across species, based on conserved gene expression programmes that are likely to trace back to an early ancestral vertebrate. The degree of variation among cell types increased from the outer retina (photoreceptors) to the inner retina (RGCs), suggesting that evolution acts preferentially to shape the retinal output. Finally, we identified rodent orthologues of midget RGCs, which comprise more than 80% of RGCs in the human retina, subserve high-acuity vision, and were previously believed to be restricted to primates2. By contrast, the mouse orthologues have large receptive fields and comprise around 2% of mouse RGCs. Projections of both primate and mouse orthologous types are overrepresented in the thalamus, which supplies the primary visual cortex. We suggest that midget RGCs are not primate innovations, but are descendants of evolutionarily ancient types that decreased in size and increased in number as primates evolved, thereby facilitating high visual acuity and increased cortical processing of visual information.

Ultrafast structural changes direct the first molecular events of vision.

Vision is initiated by the rhodopsin family of light-sensitive G protein-coupled receptors (GPCRs)1. A photon is absorbed by the 11-cis retinal chromophore of rhodopsin, which isomerizes within 200 femtoseconds to the all-trans conformation2, thereby initiating the cellular signal transduction processes that ultimately lead to vision. However, the intramolecular mechanism by which the photoactivated retinal induces the activation events inside rhodopsin remains experimentally unclear. Here we use ultrafast time-resolved crystallography at room temperature3 to determine how an isomerized twisted all-trans retinal stores the photon energy that is required to initiate the protein conformational changes associated with the formation of the G protein-binding signalling state. The distorted retinal at a 1-ps time delay after photoactivation has pulled away from half of its numerous interactions with its binding pocket, and the excess of the photon energy is released through an anisotropic protein breathing motion in the direction of the extracellular space. Notably, the very early structural motions in the protein side chains of rhodopsin appear in regions that are involved in later stages of the conserved class A GPCR activation mechanism. Our study sheds light on the earliest stages of vision in vertebrates and points to fundamental aspects of the molecular mechanisms of agonist-mediated GPCR activation.

An experimental setup for decoupling optical invariants in honeybees' altitude control.

Bees outperform pilots in navigational tasks, despite having 100,000 times fewer neurons. It is commonly accepted in the literature that optic flow is a key parameter used by flying insects to control their altitude. The ambition of the present work was to design an innovative experimental setup that would make it possible to determine whether bees could rely simultaneously on several optical invariants, as pilots do. We designed a flight tunnel to enable manipulation of an optical invariant, the Splay Angle Rate of Change (SARC) and the restriction of the Optical Speed Rate of Change (OSRC) in the optic flow. It allows us to determine if bees use the SARC to control their altitude and to identify the integration process combining these two optical invariants. Access to the OSRC can be restricted by using different textures. The SARC can be biased thanks to motorized rods. This device allows to record bees' trajectories in different visual configurations, including impoverished conditions and conditions containing contradictory information. The comparative analysis of the recorded trajectories provides first time evidence of SARC use in a ground-following task by a non-human animal. This new tunnel allows a precise experimental control of the visual environment in ecological experimental conditions. Therefore, it could pave the way for a new type of ecologically based studies examining the simultaneous use of several information sources for navigation by flying insects.

Muscles that move the retina augment compound eye vision in Drosophila.

Most animals have compound eyes, with tens to thousands of lenses attached rigidly to the exoskeleton. A natural assumption is that all of these species must resort to moving either their head or their body to actively change their visual input. However, classic anatomy has revealed that flies have muscles poised to move their retinas under the stable lenses of each compound eye1-3. Here we show that Drosophila use their retinal muscles to smoothly track visual motion, which helps to stabilize the retinal image, and also to perform small saccades when viewing a stationary scene. We show that when the retina moves, visual receptive fields shift accordingly, and that even the smallest retinal saccades activate visual neurons. Using a head-fixed behavioural paradigm, we find that Drosophila perform binocular, vergence movements of their retinas-which could enhance depth perception-when crossing gaps, and impairing the physiology of retinal motor neurons alters gap-crossing trajectories during free behaviour. That flies evolved an ability to actuate their retinas suggests that moving the eye independently of the head is broadly paramount for animals. The similarities of smooth and saccadic movements of the Drosophila retina and the vertebrate eye highlight a notable example of convergent evolution.

State-dependent pupil dilation rapidly shifts visual feature selectivity.

To increase computational flexibility, the processing of sensory inputs changes with behavioural context. In the visual system, active behavioural states characterized by motor activity and pupil dilation1,2 enhance sensory responses, but typically leave the preferred stimuli of neurons unchanged2-9. Here we find that behavioural state also modulates stimulus selectivity in the mouse visual cortex in the context of coloured natural scenes. Using population imaging in behaving mice, pharmacology and deep neural network modelling, we identified a rapid shift in colour selectivity towards ultraviolet stimuli during an active behavioural state. This was exclusively caused by state-dependent pupil dilation, which resulted in a dynamic switch from rod to cone photoreceptors, thereby extending their role beyond night and day vision. The change in tuning facilitated the decoding of ethological stimuli, such as aerial predators against the twilight sky10. For decades, studies in neuroscience and cognitive science have used pupil dilation as an indirect measure of brain state. Our data suggest that, in addition, state-dependent pupil dilation itself tunes visual representations to behavioural demands by differentially recruiting rods and cones on fast timescales.

Input-dependent segregation of visual and somatosensory circuits in the mouse superior colliculus.

Whereas sensory perception relies on specialized sensory pathways, it is unclear whether these pathways originate as modality-specific circuits. We demonstrated that somatosensory and visual circuits are not by default segregated but require the earliest retinal activity to do so. In the embryo, somatosensory and visual circuits are intermingled in the superior colliculus, leading to cortical multimodal responses to whisker pad stimulation. At birth, these circuits segregate, and responses switch to unimodal. Blocking stage I retinal waves prolongs the multimodal configuration into postnatal life, with the superior colliculus retaining a mixed somato-visual molecular identity and defects arising in the spatial organization of the visual system. Hence, the superior colliculus mediates the timely segregation of sensory modalities in an input-dependent manner, channeling specific sensory cues to their appropriate sensory pathway.

Specialization of the photoreceptor transcriptome by Srrm3-dependent microexons is required for outer segment maintenance and vision.

Retinal photoreceptors have a distinct transcriptomic profile compared to other neuronal subtypes, likely reflecting their unique cellular morphology and function in the detection of light stimuli by way of the ciliary outer segment. We discovered a layer of this molecular specialization by revealing that the vertebrate retina expresses the largest number of tissue-enriched microexons of all tissue types. A subset of these microexons is included exclusively in photoreceptor transcripts, particularly in genes involved in cilia biogenesis and vesicle-mediated transport. This microexon program is regulated by Srrm3, a paralog of the neural microexon regulator Srrm4. Despite the fact that both proteins positively regulate retina microexons in vitro, only Srrm3 is highly expressed in mature photoreceptors. Its deletion in zebrafish results in widespread down-regulation of microexon inclusion from early developmental stages, followed by other transcriptomic alterations, severe photoreceptor defects, and blindness. These results shed light on the transcriptomic specialization and functionality of photoreceptors, uncovering unique cell type-specific roles for Srrm3 and microexons with implications for retinal diseases.

Vision-related convergent gene losses reveal SERPINE3's unknown role in the eye.

Despite decades of research, knowledge about the genes that are important for development and function of the mammalian eye and are involved in human eye disorders remains incomplete. During mammalian evolution, mammals that naturally exhibit poor vision or regressive eye phenotypes have independently lost many eye-related genes. This provides an opportunity to predict novel eye-related genes based on specific evolutionary gene loss signatures. Building on these observations, we performed a genome-wide screen across 49 mammals for functionally uncharacterized genes that are preferentially lost in species exhibiting lower visual acuity values. The screen uncovered several genes, including SERPINE3, a putative serine proteinase inhibitor. A detailed investigation of 381 additional mammals revealed that SERPINE3 is independently lost in 18 lineages that typically do not primarily rely on vision, predicting a vision-related function for this gene. To test this, we show that SERPINE3 has the highest expression in eyes of zebrafish and mouse. In the zebrafish retina, serpine3 is expressed in Müller glia cells, a cell type essential for survival and maintenance of the retina. A CRISPR-mediated knockout of serpine3 in zebrafish resulted in alterations in eye shape and defects in retinal layering. Furthermore, two human polymorphisms that are in linkage with SERPINE3 are associated with eye-related traits. Together, these results suggest that SERPINE3 has a role in vertebrate eyes. More generally, by integrating comparative genomics with experiments in model organisms, we show that screens for specific phenotype-associated gene signatures can predict functions of uncharacterized genes.

Visual form of ASL verb signs predicts non-signer judgment of transitivity.

Longstanding cross-linguistic work on event representations in spoken languages have argued for a robust mapping between an event's underlying representation and its syntactic encoding, such that-for example-the agent of an event is most frequently mapped to subject position. In the same vein, sign languages have long been claimed to construct signs that visually represent their meaning, i.e., signs that are iconic. Experimental research on linguistic parameters such as plurality and aspect has recently shown some of them to be visually universal in sign, i.e. recognized by non-signers as well as signers, and have identified specific visual cues that achieve this mapping. However, little is known about what makes action representations in sign language iconic, or whether and how the mapping of underlying event representations to syntactic encoding is visually apparent in the form of a verb sign. To this end, we asked what visual cues non-signers may use in evaluating transitivity (i.e., the number of entities involved in an action). To do this, we correlated non-signer judgments about transitivity of verb signs from American Sign Language (ASL) with phonological characteristics of these signs. We found that non-signers did not accurately guess the transitivity of the signs, but that non-signer transitivity judgments can nevertheless be predicted from the signs' visual characteristics. Further, non-signers cue in on just those features that code event representations across sign languages, despite interpreting them differently. This suggests the existence of visual biases that underlie detection of linguistic categories, such as transitivity, which may uncouple from underlying conceptual representations over time in mature sign languages due to lexicalization processes.