Visual Stimuli Research Articles

Age-related Electrophysical Correlates of Cross-modal Attention Switching.

The human experience demands seamless attentional switches between sensory modalities. Aging raises questions about how declines in auditory and visual processing affect cross-modal attention switching. This study used a cued cross-modal attention-switching paradigm where visual and auditory stimuli were simultaneously presented on either spatially congruent or incongruent sides. A modality cue indicated the target modality, requiring a spatially left versus right key-press response. EEG recordings were collected during task performance. We investigated whether the mixing costs (decreased performance for repetition trials in a mixed task compared with a single task) and switch costs (decreased performance for a switch of target modality compared with a repetition) in cross-modal attention-switching paradigms would exhibit similarities in terms of behavioral performance and the ERP components to those observed in the traditional unimodal attention-switching paradigms. Specifically, we focused on the ERP components: cue-locked P3 (mixing/switch-related increased positivity), target-locked P3 (mixing/switch-related decreased positivity), and target-locked lateralized readiness potential (mixing/switch-related longer latency). In addition, we assessed how aging impacts cross-modal attention-switching performance. Results revealed that older adults exhibited more pronounced mixing and switch costs than younger adults, especially when visual and auditory stimuli were presented on incongruent sides. ERP findings showed increased cue-locked P3 amplitude, prolonged cue-locked P3 latency, decreased target-locked P3 amplitude, prolonged target-locked P3 latency in association with switch costs, and prolonged onset latency of the target-locked lateralized readiness potential in association with the mixing costs. Age-related effects were significant only for cue-locked P3 amplitude, cue-locked P3 latency (switch-related), and target-locked P3 latency (switch-related). These findings suggest that the larger mixing costs and switch costs in older adults were because of the inefficient use of modality cues to update a representation of the relevant task sets and required more processing time for evaluating and categorizing the target.

Visual long-term memory is not made more precise with medial-frontal direct-current stimulation

ABSTRACT Previous research suggests that applying anodal transcranial direct-current stimulation (tDCS) to the medial-frontal cortex can improve how quickly subjects learn to make simple discriminations (i.e., red from blue). Here, we tested the idea that this enhanced task learning is attributable to superior encoding of relevant information into visual long-term memory. Thirty subjects completed an anodal stimulation session and a sham session, with order counterbalanced across subjects, before performing recognition-memory tasks using pictures of real-world objects and visually presented words or nonwords. These tasks allowed us to detect potential memory differences across types of memoranda. Contrary to the hypothesis that the medial-frontal cortex helps control encoding fidelity, we found that anodal tDCS delivered over this brain region did not significantly improve subjects’ memory for visual stimuli, regardless of stimulus type. Our findings show no evidence that targeting medial-frontal cortex with tDCS changes the fidelity of our visual long-term memories.

Two different visual stimuli that cause axial eye shortening have no additive effect

Previous studies identified two visual stimuli that can shorten the human eye by thickening the choroid after short-term visual stimulation, potentially inhibiting myopia: (1) watching digitally filtered movies where the red plane has full spatial resolution while green and blue are low-pass filtered according to the human longitudinal chromatic aberration (LCA) function (the “red in focus” filter), and (2) reading text with inverted contrast. This study aimed to determine whether combining these two stimuli would have an additive effect on axial length. Twenty-two emmetropic subjects were recruited to read text (standard and inverted contrast) for 30 min from a large screen, 2 m away, either unfiltered or filtered with the “red in focus” filter. Axial length was measured before and after each reading episode using low-coherence interferometry (Lenstar LS 900, Haag Streit). Reading text with conventional contrast polarity (dark letters on a bright background) resulted in no significant axial length change. Adding the “red in focus” filter did not alter the outcome. Consistent with previous findings, reading inverted contrast text made emmetropic eyes shorter. Surprisingly, when the text was combined with the “red in focus” filter, eyes became longer rather than shorter. A possible explanation for this contradictory result is that, for the text stimulus, the “red in focus” filter removes spatial information in the blue channel needed by the retina to use LCA analysis to thicken the choroid.

Brain activities in the auditory area and insula represent stimuli evoking emotional response

Cinema, a modern titan of entertainment, holds power to move people with the artful manipulation of auditory and visual stimuli. Despite this, the mechanisms behind how sensory stimuli elicit emotional responses are unknown. Thus, this study evaluated which brain regions were involved when sensory stimuli evoke auditory- or visual-driven emotions during film viewing. Using functional magnetic resonance imaging (fMRI) decoding techniques, we found that brain activities in the auditory area and insula represent the stimuli that evoke emotional response. The observation of brain activities in these regions could provide further insights to these mechanisms for the improvement of film-making, as well as the development of novel neural techniques in neuroscience. In near feature, such a “neuro-designed” products/ applications might gain in popularity.

Deciphering the temporal dynamics of consumer decisions: the interplay of cognitive load and response correctness

This study delves into the impact of visual marketing stimuli on consumer response times, focusing on the complexity and subjectivity of the questions posed. Conducted in Slovakia, the research involved 40 participants (20 men and 20 women, aged 30 to 50 years), all holding university degrees in economics to ensure consistent decision-making experience. Participants were presented with visual stimuli representing four well-known FMCG brands. The stimuli included simple brand preference questions and complex evaluative judgments of offer efficiency. Response times were measured in milliseconds and analyzed using statistical methods, including the Mann-Whitney U test and one-way ANOVA. Results revealed that responses to simple stimuli averaged 1212 ms, while complex stimuli elicited slower responses, averaging 2504 ms. A significant difference was observed for “No” answers in the offer evaluation tasks, with correct “No” responses taking 3000 ms compared to 2297 ms for incorrect ones (p < 0.05), highlighting the cognitive load involved in accurate decision-making. These findings provide valuable insights into the cognitive processes driving consumer decision-making and contribute to the theoretical understanding of how question complexity and subjectivity influence response times. AcknowledgmentThis paper was funded by research grant VEGA 1/0462/23 entitled “Circular economy in the context of societal demands and market limitations“ (100% share).

High-frequency SSVEP-BCI system for detecting intermodulation frequency components using task-discriminant component analysis

Recently, steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) has significantly progressed and is moving from the laboratory to practical application. However, the system performance and comfort of SSVEP-BCIs still need to be improved. In this study, five flicker frequencies (i.e., 30–34 Hz with an interval of 1 Hz) and eight scaling frequencies (i.e., 0.4–1.8 Hz with an interval of 0.2 Hz) were adopted to jointly encode forty visual stimulus targets using evoked intermodulation (IM) frequency components. Both luminance and shape changes are implemented by sinusoidal sampling stimulus coding methods. High-frequency flicker frequencies and green visual stimuli were chosen to improve the comfort of the proposed system. An extended version of a training algorithm named task-discriminant component analysis (TDCA) was proposed to detect the IM components of SSVEP signals. The average recognition accuracy of eleven subjects is 96.82 ± 0.01 % in the offline experiments for a data length of 5 s. Online validation experiments was constructed from the optimized parameters of offline analysis, and the average accuracy and ITR were 94.37 ± 1.17 % and 113.47 ± 2.60 bits/min, respectively. Furthermore, ten subjects who participated in the validation part also completed the online free-spell task successfully. These results showed that it is feasible to expand the number of stimulus targets by using IM frequency components of SSVEP signals for target coding, and that the system performance is superior.

Functional conductivity imaging: quantitative mapping of brain activity.

Theory and modelling suggest that detection of neuronal activity may be feasible using phase sensitive MRI methods. Successful detection of neuronal activity both in vitro and in vivo has been described while others have reported negative results. Magnetic resonance electrical properties tomography may be a route by which signal changes can be identified. Here, we report successful and repeatable detection at 3 Tesla of human brain activation in response to visual and somatosensory stimuli using a functional version of tissue conductivity imaging (funCI). This detects activation in both white and grey matter with apparent tissue conductivity changes of 0.1 S/m (17-20%, depending on the tissue baseline conductivity measure) allowing visualization of complete system circuitry. The degree of activation scales with the degree of the stimulus (duration or contrast). The conductivity response functions show a distinct timecourse from that of traditional fMRI haemodynamic (BOLD or Blood Oxygenation Level Dependent) response functions, peaking within milliseconds of stimulus cessation and returning to baseline within 3-4s. We demonstrate the utility of the funCI approach by showing robust activation of the lateral somatosensory circuitry on stimulation of an index finger, on stimulation of a big toe or of noxious (heat) stimulation of the face as well as activation of visual circuitry on visual stimulation in up to five different individuals. The sensitivity and repeatability of this approach provides further evidence that magnetic resonance imaging approaches can detect brain activation beyond changes in blood supply.

Attention Modulates Human Visual Responses to Objects by Tuning Sharpening.

Visual stimuli compete with each other for cortical processing and attention biases this competition in favor of the attended stimulus. How does the relationship between the stimuli affect the strength of this attentional bias? Here, we used functional MRI to explore the effect of target-distractor similarity in neural representation on attentional modulation in the human visual cortex using univariate and multivariate pattern analyses. Using stimuli from four object categories (human bodies, cats, cars and houses), we investigated attentional effects in the primary visual area V1, the object-selective regions LO and pFs, the body-selective region EBA, and the scene-selective region PPA. We demonstrated that the strength of the attentional bias towards the target is not fixed but decreases with increasing target-distractor similarity. Simulations provided evidence that this result pattern is explained by tuning sharpening rather than an increase in gain. Our findings provide a mechanistic explanation for behavioral effects of target-distractor similarity on attentional biases and suggest tuning sharpening as the underlying mechanism in object-based attention.

Effects of color-flavor association on visual search process for reference pictures on beverage packaging: behavioral, electrophysiological, and causal mechanisms.

The visual search for product packaging involves intricate cognitive processes that are prominently impacted by learned associations derived from extensive long-term experiences. The present research employed EEG technology and manipulated the color display of reference pictures on beverage bottles to explore the underlying neurocognitive pathways. Specifically, we aimed to investigate the influence of color-flavor association strength on the visual processing of such stimuli as well as the in-depth neural mechanisms. The behavioral results revealed that stimuli with strong association strength triggered the fastest response and the highest accuracy, compared with the stimuli with weak association strength and the achromatic ones. The EEG findings further substantiated that the chromatic stimuli evoked a more pronounced N2 component than achromatic ones, and the stimuli with strong association strength elicited larger P3 and smaller N400 amplitudes than the ones with weak association strength. Additionally, the source localization using sLORETA showed significant activations in the inferior temporal gyrus. In conclusion, our research suggests that (1) color expectations would guide visual search process and trigger faster responses to congruent visual stimuli, (2) both the initial perceptual representation and subsequent semantic representation play pivotal roles in effective visual search for the targets, and (3) the color-flavor association strength potentially exerts an impact on visual processing by modulating memory accessibility.

How labels shape visuocortical processing in infants.

The current study examined the extent to which labels shape visuocortical processing during the first year of life during a brief (~6-min) associative learning task. Images of computer-generated artificial objects were paired with either individual-level (e.g., Jimmy, Boris) or category-level labels (e.g., Hitchel) while event-related potentials were recorded in response to the onset of the visual stimulus in 6- (n=41), 9- (n=27), and 12-month-old (n=28) infants. Analyses examined experience-dependent visuocortical changes within and across trials, label conditions, and ages. Overall, results demonstrate that infants deploy greater visuocortical resources during the first half of associative learning trials and to stimuli paired with category-level relative to individual-level labels. Waveform morphologies also differed between stimuli paired with individual- and category-level labels and across the age groups, with more complex deflections and amplitude differences between label type at 9- and 12-month-olds, but not 6-month-old infants. The present results highlight the importance of associative learning during infancy and suggest that category- versus individual-level labels differentially direct infant attention and visuocortical processing.

Sham feeding as a nursing technology: recent progress and future perspective

Abstract Sham feeding is a conventional technique employed in enhanced recovery after surgery (ERAS) protocols to facilitate the restoration of gastrointestinal motility. Currently, effectiveness of sham feeding extends beyond the postoperative phase following abdominal surgery, demonstrating potential applicability in non-abdominal postoperative rehabilitation. Studies have shown that sham feeding triggers the head-vagal reflex, thereby promoting gastrointestinal motility through a combination of humoral and neural stimulation. Recognized as a highly promising ERAS technology, sham feeding needs to be further investigated regarding the form, mechanism, and application of sham feeding. This paper summarized the research progress and limitations of sham feeding. Considering contemporary research focus on the gut-brain axis, we proposed a new concept of sham feeding that integrates visual, auditory, and olfactory stimuli. Additionally, we provide suggestions and perspectives to guide future exploration of sham feeding for its potential impact on development of non-drug nursing intervention technology based on the concept of ERAS.

Neural Basis of Number Sense in Larval Zebrafish.

Number sense, the ability to discriminate the quantity of objects, is crucial for survival. To understand how neurons work together and develop to mediate number sense, we used two-photon fluorescence light sheet microscopy to capture the activity of individual neurons throughout the brain of larval Danio rerio, while displaying a visual number stimulus to the animal. We identified number-selective neurons as early as 3 days post-fertilization and found a proportional increase of neurons tuned to larger quantities after 3 days. We used machine learning to predict the stimulus from the neuronal activity and observed that the prediction accuracy improves with age. We further tested ethanol's effect on number sense and found a decrease in number-selective neurons in the forebrain, suggesting cognitive impairment. These findings are a significant step towards understanding neural circuits devoted to discrete magnitudes and our methodology to track single-neuron activity across the whole brain is broadly applicable to other fields in neuroscience.

Unestablished Boundaries: The Capabilities of Immersive Technologies to Induce Empathy, Tell Stories, and Immerse

This article presents a critical viewpoint on the existing research to establish the boundaries of immersive technologies, such as virtual reality, exploring distinctions between sensorial and mental experiences and highlighting the influence of technological determinism in this scholarly domain. The analysis reveals a lack of established conceptual structures for categorizing distinct types of immersion, emphasizing that immersion is not universal and is not inherently technological. In particular, it highlights that, fundamentally, immersive technologies are not designed to immerse into narratives. As a result, this article suggests a dual cognitive framework of immersion to explain the nature of different immersive experiences. The article also critically addresses ethical concerns related to identity tourism and argues against the oversimplification of complex psychological processes, emphasizing the overreliance of the existing studies on visual or technological stimuli. To avoid this, the article suggests a way to avoid technological determinism in relevant conceptualizations. Overall, the article scrutinizes the assumptions associated with immersive technologies, offering insights into their capabilities to stimulate senses and vividly inform, contributing to a nuanced understanding of their effects and ethical implications.

Interoceptive signals shape the earliest markers and neural pathway to awareness at the visual threshold

Variations in interoceptive signals from the baroreceptors (BRs) across the cardiac and respiratory cycle can modulate cortical excitability and so affect awareness. It remains debated at what stages of processing they affect awareness-related event-related potentials (ERPs) in different sensory modalities. We investigated the influence of the cardiac (systole/diastole) and the respiratory (inhalation/exhalation) phase on awareness-related ERPs. Subjects discriminated visual threshold stimuli while their electroencephalogram, electrocardiogram, and respiration were simultaneously recorded. We compared ERPs and their intracranial generators for stimuli classified correctly with and without awareness as a function of the cardiac and respiratory phase. Cyclic variations of interoceptive signals from the BRs modulated both the earliest electrophysiological markers and the trajectory of brain activity when subjects became aware of the stimuli: an early sensory component (P1) was the earliest marker of awareness for low (diastole/inhalation) and a perceptual component (visual awareness negativity) for high (systole/exhalation) BR activity, indicating that BR signals interfere with the sensory processing of the visual input. Likewise, activity spread from the primary visceral cortex (posterior insula) to posterior parietal cortices during high and from associative interoceptive centers (anterior insula) to the prefrontal cortex during low BR activity. Consciousness is thereby resolved in cognitive/associative regions when BR is low and in perceptual centers when it is high. Our results suggest that cyclic fluctuations of BR signaling affect both the earliest markers of awareness and the brain processes underlying conscious awareness.

Bilateral connections from the amygdala to extrastriate visual cortex in the marmoset monkey.

It is known that the primate amygdala forms projections to many areas of the ipsilateral cortex, but the extent to which it forms connections with the contralateral visual cortex remains less understood. Based on retrograde tracer injections in marmoset monkeys, we report that the amygdala forms widespread projections to the ipsilateral extrastriate cortex, including V1 and areas in both the dorsal (MT, V4T, V3a, 19M, and PG/PFG) and the ventral (VLP and TEO) streams. In addition, contralateral projections were found to target each of the extrastriate areas, but not V1. In both hemispheres, the tracer-labeled neurons were exclusively located in the basolateral nuclear complex. The number of labeled neurons in the contralateral amygdala was small relative to the ipsilateral connection (1.2% to 5.8%). The percentage of contralateral connections increased progressively with hierarchical level. An injection in the corpus callosum demonstrated that at least some of the amygdalo-cortical connections cross through this fiber tract, in addition to the previously documented path through the anterior commissure. Our results expand knowledge of the amygdalofugal projections to the extrastriate cortex, while also revealing pathways through which visual stimuli conveying affective content can directly influence early stages of neural processing in the contralateral visual field.

Effects of enriched environments on behavioral development at toddler period of preterm experienced early repeated procedural pain

Objective: To investigate the effects of enriched environments on behavioral development at toddler period of preterm who had experienced early repeated operative pain. Methods: A cross-sectional study was conducted. A total of 80 high-risk preterm children of 2 years of age, who had experienced repeated pain stimuli in the neonatal intensive care unit (NICU), were enrolled as preterm group from the High-risk Children Clinic of Children's Hospital of Nanjing Medical University from October 2016 to March 2021. Furthermore, 39 full-term healthy children, aged 2 years, who were undergoing routine check-ups during the same period, were selected as the full-term group. The preterm group was further divided into preterm intervention group and preterm non-intervention group based on the implementation of enriched environment interventions. Data of neonatal characteristics from 3 groups were collected. Growth and development indicators at the age of 2 years were measured. Neuropsychological development evaluated by Gesell developmental scale. Behavioral development evaluated by child behavior check list. The salivary cortisol levels in response to novelty (baseline, task, end) were collected. The family environment, including maternal parenting pressure, were evaluated through a survey questionnaire. One-way ANOVA and least significant difference (LSD) tests were used to compare physical development, maternal parenting stress, Gesell neuropsychological development, and behavioral problems among the 3 groups. A repeated-ANOVA and LSD tests were employed to compare the patterns of salivary cortisol secretion. Pearson correlation analysis was used to explore the influencing factors related to neuropsychological and behavioral development and cortisol level. Results: There were 44 cases in the preterm intervention group (17 males, gestational age of (31.3±2.8) weeks), and 36 in the preterm non-intervention group (29 males, gestational age of (32.5±2.6) weeks). The full-term group consisted of 39 children (23 males, gestational age of (39.3±2.1) weeks). At 2 years of age, the height, weight, and head circumference of the preterm intervention group and non-intervention group were all lower than those of the full-term group (all P<0.05).The Gesell developmental schedule showed that the preterm non-intervention group scored all lower in gross motor, fine motor, adaptive, language and personal-social domains compared to the full-term group (91±7 vs. 97±6, 88±9 vs. 94±6, 89±8 vs. 99±8, 84±10 vs. 100±15, 89±7 vs. 95±6), with statistical significance (all P<0.01). The preterm intervention group scored all higher than the preterm non-intervention group in gross motor, fine motor, adaptive and language domains (all P<0.05), with no significant difference compared to the full-term group (all P>0.05). The number of needle painful procedures during hospitalization in NICU of the non-intervention group was negatively correlated to the adaptive development quotient (r=-0.48, P<0.05). Furthermore, the preterm non-intervention group exhibited higher scores in social withdrawal, depression, somatic complaints, aggression, and destructive behaviors compare to the full-term group and preterm intervention group (F=8.07, 5.67, 7.72, 7.90, 7.06; all P<0.05); while the preterm intervention group showed no significant difference compared to full-term group (all P>0.05). Behavioral problems (social withdrawal and depression) in the preterm non-intervention group were positively correlated with maternal parenting stress (r=0.66, 0.50; both P<0.05). In response to novel visual stimuli and cognitive challenges, the preterm non-intervention group had significantly higher salivary cortisol levels compared to the full-term group (P=0.006), which were negatively correlated with the frequency of early painful procedures (r=-0.83, -0.80; both P<0.01). There was no significant difference in cortisol secretion pattern between the intervention group and the full-term group (P=0.772). Conclusion: Enriched environmental interventions can improve neuropsychological development, decrease behavioral problems, and down-regulate consistent high cortisol response to task in preterm infants who have experienced repeated procedural pain in the NICU by the age of 2 years.

Cognitive performance of grey mouse lemurs (Microcebus murinus) during a discrimination learning task: Effect of the emotional valence of stimuli.

Emotions are omnipresent in many animals' lives. It is a complex concept that encompasses physiological, subjective, behavioural and cognitive aspects. While the complex relationship between emotion and cognition has been well studied in humans and in some nonhuman primates, it remains rather unexplored for other nonhuman primate species, such as lemurs. In our study, we evaluated the performance of N = 48 grey mouse lemurs (Microcebus murinus) in a discrimination learning task using visual emotional stimuli. We tested whether the type of visual stimulus (positive, negative or neutral) influenced the cognitive performance of mouse lemurs. Individuals had to learn to discriminate between two platforms according to the associated visual stimuli and to jump to the target platform (leading to a reward). Our main finding was that emotional stimuli, whether positive or negative in valence, impaired cognitive performance when used as a target. Specifically, the lowest success rate occurred when the target was associated with the emotional stimuli, and the highest success rate occurred when it was associated with neutral stimuli. Our results show a similar pattern to that found in other primate species and support the adaptive role of emotion. Our results also support that individual differences could be a factor impacting the relation between emotion and cognition. This study is the first to explore how emotions interfere with the cognitive abilities of a lemur species and highlights the importance of acknowledging emotion in mouse lemurs as well as studying the emotion-cognition interaction in a wider range of primate species.

Sensory room: Naturalistic assessment of auditory and visual perception in developing children

IntroductionHearing is essential for language acquisition and understanding the environment. Understanding how children react to auditory and visual information is essential for appropriate management in case of hearing loss. Objective and subjective assessments can diagnose hearing loss, but do not measure natural perception in children. We developed a “sensory room” for complementary assessment of children's perceptions so as to assess behavioral responses to meaningful natural sounds and visual stimuli in an ecologic environment suited to children. Material and methodsSixteen normal-hearing children and 10 with congenital hearing loss before cochlear implantation, aged 13 to 32months, were included in this feasibility study. They perceived 18 environmental sounds and 9 visual stimuli, and their behavioral responses were coded accordingly as: stopping, looking, moving, pointing, language or emotional reactions. ResultAll children completed the task, demonstrating its feasibility in children. Percentage responses to auditory versus visual stimuli did not differ in normal-hearing children; those with congenital hearing loss responded like normal-hearing children to visual stimuli, but did not react to auditory stimuli. Progression in normal-hearing children's behavioral responses corresponded to cognitive and linguistic development according to age. ConclusionThe “sensory room” quantified children's responses to various auditory and visual stimuli, providing clinicians with measurable insight into the children's sensory perception and processing.

Brain Wave Changes in the Prefrontal Cortex When Exposed to Varying Plant Types as Visual Stimuli

Visual stimuli from green plants have positive effects on mental health. This study aimed to compare human responses to varying plant types [live, artificial, two-dimensional (2D), and three-dimensional (3D) plant models] as visual stimuli. Thirty adults (age, 29.9 ± 11.5 years) viewed each plant form while an electroencephalography (EEG) measured their brain activity. Psychological responses were assessed using the semantic differential method (SDM). No significant differences were observed among visual stimuli; however, brain activity differences varied between male and female participants. Males who observed live and artificial plants had a higher relative alpha (RA) spectrum (RAS) and relative fast alpha (RFA) spectrum frequencies at Fp1 and Fp2 (P &lt; 0.05 and P &lt; 0.01 vs. P &lt; 0.05 and P &lt; 0.01, respectively), indicating greater emotional stability. Similarly, male participants who viewed 2D models had higher RA and RFA frequencies at Fp1 (P &lt; 0.01, P &lt; 0.01) and Fp2 (P &lt; 0.05, P &lt; 0.01). Male participants who observed 3D models exhibited higher RA, RSA, and RFA frequencies at Fp1 (P &lt; 0.01). Live and artificial plants were deemed the most calming (P &lt; 0.01). Both sexes found live plants to be the most pleasant (males: P &lt; 0.01; females: P &lt; 0.05) and natural (males: P &lt; 0.001; females: P &lt; 0.01). Overall, alpha wave differences were not significant among plant types, and live plants elicited a trend toward emotional stability. These findings suggest that 3D plant models can be as effective as real plants in psychophysiological applications, indicating their potential benefits for enhancing mental health in urban environments.

Improving Depth Perception in Immersive Media Devices by Addressing Vergence-Accommodation Conflict.

Recently, immersive media devices have seen a boost in popularity. However, many problems still remain. Depth perception is a crucial part of how humans behave and interact with their environment. Convergence and accommodation are two physiological mechanisms that provide important depth cues. However, when humans are immersed in virtual environments, they experience a mismatch between these cues. This mismatch causes users to feel discomfort while also hindering their ability to fully perceive object distances. To address the conflict, we have developed a technique that encompasses inverse blurring into immersive media devices. For the inverse blurring, we utilize the classical Wiener deconvolution approach by proposing a novel technique that is applied without the need for an eye-tracker and implemented in a commercial immersive media device. The technique's ability to compensate for the vergence-accommodation conflict was verified through two user studies aimed at reaching and spatial awareness, respectively. The two studies yielded a statistically significant 36% and 48% error reduction in user performance to estimate distances, respectively. Overall, the work done demonstrates how visual stimuli can be modified to allow users to achieve a more natural perception and interaction with the virtual environment.