Effect Of Illusion Research Articles

Transcranial Direct Current Stimulation and Visual Illusion Effect According to Sensory Phenotypes in Patients With Spinal Cord Injury and Neuropathic Pain

Treatment of neuropathic pain (NP) in patients with spinal cord injury (SCI) remains a major challenge. The aim of the present study is to investigate if the effect of transcranial direct current stimulation combined with visual illusion, following a previously published protocol, has differential effects on pain-related sensory symptoms according to sensory phenotypes profiles. One hundred and thirty SCI patients with NP participated in this open-label trial. Sixty-five patients were given a daily 20-minutes combined treatment of transcranial direct current stimulation and visual illusion for 2 weeks. Sixty-five patients served as a control group. Clinical assessment was performed before and 2 weeks later, by using Neuropathic Pain Symptom Inventory (NPSI), Brief Pain Inventory, and Patient Health Questionnaire-9. There was significant improvement in the combined treatment group according to NPSI, Brief Pain Inventory, and Patient Health Questionnaire-9, but no changes in the control group. Following a cluster analysis of NPSI items at baseline assessment, 5 subgroups of patients with different pain-related characteristics were identified among the treated group, although differences between clusters were not significant. There was also improvement in mood, sleep quality, and enjoyment of life in the treated group. Despite a reduction of NP with the combined treatment, the analysis of sensory phenotype pain profiles does not provide a predictive value regarding the analgesic results of this combined neuromodulatory treatment. PerspectiveIn this article we confirm the analgesic effect of a combined neuromodulatory therapy, transcranial direct current stimulation associated with visual illusion in patients with NP after an SCI. We have identified 5 clusters of NP with distinct sensory phenotypes, but there was not any specific sensory phenotype cluster that significantly responded to the combined therapy better than the other.

The effect of multisensory illusions on pain and perceived burning sensations in patients with Burning Mouth Syndrome: A proof-of-concept study.

Burning mouth syndrome (BMS) is a chronic pain disorder affecting the oral cavity. Previous work has shown promising analgesic results of bodily illusions in other chronic pain conditions. The aim of this proof-of-concept, pilot study was to investigate whether bodily illusions reduce pain in BMS patients. Nine participants diagnosed with BMS underwent bodily illusions using a MIRAGE-mediated reality system. All participants completed four conditions and performed standardised movements of the tongue. First, a baseline condition was performed while the tongue was viewed at normal size and colour. Then, three conditions were performed in random order: resizing shrink, colour-based (blue tongue) and incongruent movement illusions. During each condition, participants rated overall pain intensity and the intensity of burning pain/sensation on the tongue. There was no difference in overall pain intensity ratings between conditions. However, a significant effect of condition was found for burning pain/sensation of the tongue. The colour illusion significantly reduced burning pain compared with baseline (MD=-12.8, 95% CI -20.7 to -4.8), corresponding to an average pain reduction of 32%. Exploratory analyses showed the colour illusion also significantly reduced pain compared with the shrink illusion (MD=-11.7, 95% CI -22.2 to -1.1). Using visual illusions to change tongue colour to blue resulted in significant reductions in burning pain/sensations in BMS patients for the duration of the illusion. This proof-of-concept study suggests that BMS patients may benefit from bodily illusions, and supports additional research using larger samples and more comprehensive control conditions.

Augmenting Perceived Softness of Haptic Proxy Objects Through Transient Vibration and Visuo-Haptic Illusion in Virtual Reality

In this article, we investigate the effects of active transient vibration and visuo-haptic illusion to augment the perceived softness of haptic proxy objects. We introduce a system combining active transient vibration at the fingertip with visuo-haptic illusions. In our hand-held device, a voice coil actuator transmits active transient vibrations to the index fingertip, while a force sensor measures the force applied on passive proxy objects to create visuo-haptic illusions in virtual reality. We conducted three user studies to understand both the vibrotactile effect and its combined effect with visuo-haptic illusions. A preliminary study confirmed that active transient vibrations can intuitively alter the perceived softness of a proxy object. Our first study demonstrated that those same active transient vibrations can generate different perceptions of softness depending on the material of the proxy object used. In our second study, we evaluated the combination of active transient vibration and visuo-haptic illusion, and found that both significantly influence perceived softness, with with the visuo-haptic effect being dominant. Our third study further investigated the vibrotactile effect while controlling for the visuo-haptic illusion. The combination of these two methods allows users to effectively perceive various levels of softness when interacting with haptic proxy objects.

Alternative explanation of the money illusion: The effect of unexpected low inflation

In this study, a theoretical framework was constructed to verify whether the inflation level determines the presence of money illusion. The unexpected occurrence of low inflation is typically taken as an indication that the economy has entered or is entering a recession, and people expect the Federal Reserve to rapidly intervene to recover the economy. Because rental contracts facilitate rent price rigidity, rent prices may not decline immediately in the presence of unexpected low inflation, causing house owners in general to consider their rent returns as still lucrative. The excess profits from the rent returns of house owners can be used to compensate potential loss incurred from falling housing prices in the future, subsequently reducing their risk of property ownership. Therefore, when encountering unexpected low inflation, house owners tend to lower their expectations of housing return risk and overestimate the housing price, thus resulting in money illusion effects. A long-term data set of the US housing market (sample period: 1960 Q1 – 2016 Q1) was employed to comprehensively estimate the biases of the price–rent ratio. The estimation results revealed that money illusion effects only exist in conditions with minimal commodity price increases or decreases, which comply with the hypothesis of the present study. Finally, this study evaluated expected housing risk and housing premiums and confirmed that unexpected low inflation increases housing premiums, consequently leading to a higher rise in housing prices than in rent prices and contributing to the mispricing of price–rent ratios.

Effects of Rubber Hand Illusion and Excitatory Theta Burst Stimulation on Tactile Sensation: A Pilot Study.

Synchronous visuotactile stimulation on the own hidden hand and a visible fake limb can alter bodily self-perception and influence spontaneous neuroplasticity. The rubber hand illusion (RHI) paradigm experimentally produces an illusion of rubber hand ownership and arm shift by simultaneously stroking a rubber hand in view and a participant's visually occluded hand. The aim of this cross-over, placebo-controlled, single-blind study was to assess whether RHI, in combination with high-frequency repetitive transcranial magnetic stimulation (rTMS) given as intermittent (excitatory) theta burst stimulation (iTBS) applied over the hand area of the primary sensory region (S1) can enhance tactile sensation in a group of 21 healthy subjects and one patient with cervical spinal cord injury. Four sessions covered all combinations of real and sham stimulations of the RHI and the TBS: real TBS and real RHI, real TBS and sham RHI, sham TBS and real RHI, and both conditions sham. The condition sham TBS and real RHI shows the greatest effect on the proprioceptive drift (median 2.3 cm, IQR 2) and on the score of RHI questionnaires (median 3, IQR 2) in the control group as well as in the real-real condition (median 2, IQR 2). The sham TBS and real RHI condition also shows the best results in the electrical perception test of the patient (median 1.9 mA). Conversely, the upregulation of the cortical excitability of S1 via TBS seems to impair the effect of the RHI. This might be due to a strengthening of the top-down connection between the central nervous system and the periphery, diminishing the RHI. This finding helps in understanding the mechanisms of top-down and bottom-up mechanisms in healthy subjects and patients with spinal cord injury. The RHI paradigm could represent an interesting therapeutic approach in improving tactile sensation and rTMS techniques could modulate these effects. Yet, further studies are needed, to examine the direction of the interaction effect of TMS and RH.

VibeRo: Vibrotactile Stiffness Perception Interface for Virtual Reality

Haptic interfaces allow a more realistic experience with Virtual Reality (VR). They are used to manipulate virtual objects. These objects can be rigid and soft. In this letter, we have designed and evaluated a vibrotactile hand-held device (VibeRo) to achieve haptic cues of different soft objects. The proposed method is based on combining the vision-driven displacement produced by the pseudo-haptics effect with the haptic illusion of a limb displacement obtained from force-driven synthesis of vibration of a contact surface. VibeRo features a voice-coil actuator and force-sensitive resistors for generating squeeze forces at fingertips. We present an evaluation of VibeRo's pseudo-haptic and haptic illusion effects to render soft virtual objects. The efficacy of the approach was validated in experiments with human subjects.

Role of kinaesthetic motor imagery in mirror-induced visual illusion as intervention in post-stroke rehabilitation.

Mirror-induced visual illusion obtained through mirror therapy is widely used to facilitate motor recovery after stroke. Activation of primary motor cortex (M1) ipsilateral to the moving limb has been reported during mirror-induced visual illusion. However, the mechanism through which the mirror illusion elicits motor execution processes without movements observed in the mirrored limb remains unclear. This study aims to review evidence based on brain imaging studies for testing the hypothesis that neural processes associated with kinaesthetic motor imagery are attributed to ipsilateral M1 activation. Four electronic databases were searched. Studies on functional brain imaging, investigating the instant effects of mirror-induced visual illusion among stroke survivors and healthy participants were included. Thirty-five studies engaging 78 stroke survivors and 396 healthy participants were reviewed. Results of functional brain scans (n = 20) indicated that half of the studies (n = 10, 50%) reported significant changes in the activation of ipsilateral M1, which mediates motor preparation and execution. Other common neural substrates included primary somatosensory cortex (45%, kinaesthesia), precuneus (40%, image generation and self-processing operations) and cerebellum (20%, motor control). Similar patterns of ipsilateral M1 activations were observed in the two groups. These neural substrates mediated the generation, maintenance, and manipulation of motor-related images, which were the key processes in kinaesthetic motor imagery. Relationships in terms of shared neural substrates and mental processes between mirror-induced visual illusion and kinaesthetic motor imagery generate new evidence on the role of the latter in mirror therapy. Future studies should investigate the imagery processes in illusion training for post-stroke patients.

Why some size illusions affect grip aperture

There is extensive literature debating whether perceived size is used to guide grasping. A possible reason for not using judged size is that using judged positions might lead to more precise movements. As this argument does not hold for small objects and all studies showing an effect of the Ebbinghaus illusion on grasping used small objects, we hypothesized that size information is used for small objects but not for large ones. Using a modified diagonal illusion, we obtained an effect of about 10% on perceptual judgements, without an effect on grasping, irrespective of object size. We therefore reject our precision hypothesis. We discuss the results in the framework of grasping as moving digits to positions on an object. We conclude that the reported disagreement on the effect of illusions is because the Ebbinghaus illusion not only affects size, but—unlike most size illusions—also affects perceived positions.

Effects of Repetition Suppression on Sound Induced Flash Illusion With Aging.

The sound-induced flash illusion (SiFI) is a classical auditory-dominated multisensory integration phenomenon in which the observer misperceives the number of visual flashes due to the simultaneous presentation of a different number of auditory beeps. Although the SiFI has been documented to correlate with perceptual sensitivity, to date there is no consensus as to how it corresponds to sensitivity with aging. The present study was based on the SiFI paradigm (Shams et al., 2000), adding repeated auditory stimuli prior to the appearance of audiovisual stimuli to investigate the effects of repetition suppression (RS) on the SiFI with aging. The repeated auditory stimuli consisted of one or two of the same auditory stimuli presented twice in succession, which were then followed by the audiovisual stimuli. By comparing the illusions in old and young adults, we aimed to explore the influence of aging on the RS of auditory stimuli on the SiFI. The results showed that both age groups showed SiFI effects, however, the RS performance of the two age groups had different effects on the fusion and fission illusions. The illusion effect in old adults was weaker than in young adults. Specifically, RS only affected fission illusions in the old adults but both fission and fusion illusions in young adults. Thus, the present study indicated that the decreased perceptual sensitivity based on auditory RS could weaken the SiFI effect in multisensory integration and that old adults are more susceptible to RS, showing that old adults perceived the SiFI effect weakly under auditory RS.

Ebbinghaus visual illusion: no robust influence on novice golf-putting performance.

Do visual illusions reliably improve sports performance? To address this issue, we used procedures inspired by Witt et al. (Psychol Sci 23:397-399, 2012) seminal study, which reported that putting on a miniature golf course was positively influenced by an increase in apparent hole size induced by the Ebbinghaus visual illusion. Because Witt et al.'s motor task-putting golf balls toward a hole from the distance of 3.5m-was impossible for participants who were novices in golf (Experiment 1a), we decided to shorten the putting distance (i.e., 2m instead of 3.5m) in Experiment 1b. Otherwise, this second experiment closely followed every other aspects of Witt et al.'s procedure (i.e., one small or one standard golf hole surrounded by a ring of small or large circles). However, this attempt to replicate Witt et al.'s findings failed: the Ebbinghaus illusion significantly influenced neither hole perception nor putting performance. In two subsequent experiments, we encouraged the emergence of the effect of the illusion by simultaneously presenting both versions of the illusion on the mat. This major adaptation successfully modified the perceived size of the hole but had no impact on putting performance (Experiment 2), even when the putting task was made easier by shortening the putting distance to only 1m (Experiment 3). In the absence of detectable effects of the illusion on putting performance, we conclude that the effects of visual illusions on novice sports performance do not represent a robust phenomenon.

Causal illusion as a cognitive basis of pseudoscientific beliefs.

Causal illusion has been proposed as a cognitive mediator of pseudoscientific beliefs. However, previous studies have only tested the association between this cognitive bias and a closely related but different type of unwarranted beliefs, those related to superstition and paranormal phenomena. Participants (n=225) responded to a novel questionnaire of pseudoscientific beliefs designed for this study. They also completed a contingency learning task in which a possible cause, infusion intake, and a desired effect, headache remission, were actually non-contingent. Volunteers with higher scores on the questionnaire also presented stronger causal illusion effects. These results support the hypothesis that causal illusions might play a fundamental role in the endorsement of pseudoscientific beliefs.

Penyutradaraan Dan Editing Dalam Pembuatan Film Animasi 3D Bergenre Action Berjudul “Beda�


 The objective to be achieved in this Final Project is to produce an Action Animation 3D Film titled "DIFFERENT". This Final Project will use the theme of Racial Differences or Racism, with stories about conditions that will occur if there continues to be conflict due to differences. This work was made because of the increasing number of cases of racial differences (SARA) that are getting worse and worse. This racial difference occurs mostly because it is motivated by the desires of individuals or groups who want to be the best of other races, individuals or groups. Race is a categorization or grouping of humans based on the physical characteristics of the body. This Final Project will use qualitative research methods using data collection techniques in the form of interviews, literature studies, observations, and existing studies. In this 3D animated film, it will use the back and forth flow, displaying Fantasy stories with action genres and combined with visual effects of digital illusions, focusing on stories between 2 characters namely the main character "N" and the female lead character "Princess" who promised to end the war, lasted 12 minutes. With the creation of this short film, it is hoped that it can add insight into the meaning of racial differences and can respect differences.

Audiovisual Illusion Effects in Multisensory Integration in Elderly Adults

Multisensory integration; Multisensory illusion effect; Old adults

Projection Mapping Using Optical Illusion Effect for Digitizing Gimmick Picture Books

In this paper, an electronic “gimmick picture book” whose contents pop up when its pages are flipped is proposed. From educational aspect, the gimmick picture books are appropriate for training children’s cultivate imagination and special recognition abilities. However, production of the handmade gimmick requires high technical skills. Our proposed method realizes the gimmick by combination of a projection mapping method and a trick art technique which is used for a pseudo stereoscopic image.

A Case Series Clinical Trial of a Novel Approach Using Augmented Reality That Inspires Self-body Cognition in Patients With Stroke: Effects on Motor Function and Resting-State Brain Functional Connectivity.

Barring a few studies, there are not enough established treatments to improve upper limb motor function in patients with severe impairments due to chronic stroke. This study aimed to clarify the effect of the kinesthetic perceptional illusion induced by visual stimulation (KINVIS) on upper limb motor function and the relationship between motor function and resting-state brain networks. Eleven patients with severe paralysis of upper limb motor function in the chronic phase (seven men and four women; age: 54.7 ± 10.8 years; 44.0 ± 29.0 months post-stroke) participated in the study. Patients underwent an intervention consisting of therapy using KINVIS and conventional therapeutic exercise (TherEX) for 10 days. Our originally developed KiNvis™ system was applied to induce KINVIS while watching the movement of the artificial hand. Clinical outcomes were examined to evaluate motor functions and resting-state brain functional connectivity (rsFC) by analyzing blood-oxygen-level-dependent (BOLD) signals measured using functional magnetic resonance imaging (fMRI). The outcomes of motor function (Fugle-Meyer Assessment, FMA) and spasticity (Modified Ashworth Scale, MAS) significantly improved after the intervention. The improvement in MAS scores for the fingers and the wrist flexors reached a minimum of clinically important differences. Before the intervention, strong and significant negative correlations between the motor functions and rsFC of the inferior parietal lobule (IPL) and premotor cortex (PMd) in the unaffected hemisphere was demonstrated. These strong correlations were disappeared after the intervention. A negative and strong correlation between the motor function and rsFC of the bilateral inferior parietal sulcus (IPS) significantly changed to strong and positive correlation after the intervention. These results may suggest that the combination approach of KINVIS therapy and TherEX improved motor functions and decreased spasticity in the paralyzed upper extremity after stroke in the chronic phase, possibly indicating the contribution of embodied-visual stimulation. The rsFC for the interhemispheric IPS and intrahemispheric IPL and PMd may be a possible regulatory factor for improving motor function and spasticity.Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT01274117.

The effects of risk aversion and money illusion on the components of dividend growth rate

ABSTRACTWe evaluate the impact of risk aversion and money illusion in the equity and options markets when the expected dividend growth rate is endogenously determined as a function of the dividend-price ratio and expected inflation. The closed-form equilibrium expressions for the dividend-price ratio, expected inflation, and dividend growth rate allow us to perform comparative statics to understand their sensitivity relative to the agent's preference parameters. Our calibration exercise indicates that the sensitivity of the dividend-price ratio relative to risk aversion depends critically on the sign of the exposure of the expected dividend growth rate to the divided yield, while an increase in the degree of money illusion always raises the dividend-price ratio, irrespective of its exposure to the dividend yield. In addition, we show that expected inflation is much less sensitive to variations in risk aversion and money illusion than these parameters, while the price of a zero-coupon caplet is affected in the opposite direction by these parameters.

Illusion mechanisms with cylindrical metasurfaces: A general synthesis approach

We explore the use of cylindrical metasurfaces in providing several illusion mechanisms including scattering cancellation and creating fictitious line sources. We present the general synthesis approach that leads to such phenomena by modeling the metasurface with effective polarizability tensors and by applying boundary conditions to connect the tangential components of the desired fields to the required surface polarization current densities that generate such fields. We then use these required surface polarizations to obtain the effective polarizabilities for the synthesis of the metasurface. We demonstrate the use of this general method for the synthesis of metasurfaces that lead to scattering cancellation and illusion effects, and discuss practical scenarios by using loaded dipole antennas to realize the discretized polarization current densities. This study is the first fundamental step that may lead to interesting electromagnetic applications, like stealth technology, antenna synthesis, wireless power transfer, sensors, cylindrical absorbers, etc.

Decrease of the tilt illusion effect through perceptual learning

Decrease of the tilt illusion effect through perceptual learning

The Effect of a Virtual-Reality Full-Body Illusion on Body Representation in Obesity.

Background. The effective illusory ownership over an artificial body in modulating body representations in healthy and eating disorders population has been repeatedly reported in recent literature. In this study, we extended this research in the field of obesity: specifically, we investigated whether ownership over a virtual body with a skinny abdomen might be successfully experienced by participants affected by obesity. Methods. Fifteen participants with obesity and fifteen healthy-weight participants took part at this study in which the VR-Full-Body Illusion was adopted. The strength of illusion was investigated through the traditional Embodiment Questionnaire, while changes in bodily experience were measured through a body size estimation task. Results. Participants with obesity as well as healthy-weight participants reported to experience the illusion. About the body size estimation task, both groups reported changes only in the estimation of the abdomen’s circumference after the experimental condition, in absence of any another difference. Discussion. Participants with obesity reported to experience the illusion over a skinny avatar, but the modulation of the bodily experience seems controversial. Future lines of research exploiting this technique for modulating body representations in obesity, specifically in terms of potential therapeutic use, were discussed.

What is the effect of bodily illusions on corticomotoneuronal excitability? A systematic review.

BackgroundThis systematic review aimed to summarise and critically appraise the evidence for the effect of bodily illusions on corticomotoneuronal excitability.MethodsFive databases were searched, with two independent reviewers completing study inclusion, risk of bias, transcranial magnetic stimulation (TMS) reporting quality, and data extraction. Included studies evaluated the effect of an illusion that altered perception of the body (and/or its movement) on excitability of motor circuitry in healthy, adult, human participants. Studies were required to: use TMS to measure excitability and/or inhibition; report quantitative outcomes (e.g., motor evoked potentials); compare the illusion to a control or active comparison condition; evaluate that an illusion had occurred (e.g., measured illusion strength/presence).ResultsOf 2,257 studies identified, 11 studies (14 experiments) were included, evaluating kinaesthetic illusions (n = 5), a rubber hand illusion (RHI) paradigm (n = 5), and a missing limb illusion (n = 1). Kinaesthetic illusions (induced via vision/tendon vibration) increased corticomotoneuronal excitability. Conflicting effects were found for traditional, visuotactile RHIs of a static hand. However, embodying a hand and then observing it move (“self-action”) resulted in decreased corticomotoneuronal excitability and increased silent period duration (a measure of Gamma-Aminobutynic acid [GABA]B-mediated intracortical inhibition in motor cortex), with the opposite occurring (increased excitability, decreased inhibition) when the fake hand was not embodied prior to observing movement (“other-action”). Visuomotor illusions manipulating agency had conflicting results, but in the lower risk study, illusory agency over movement resulted in a relative decrease in corticomotoneuronal excitability. Last, an illusion of a missing limb reduced corticomotoneuronal excitability.ConclusionWhile evidence for the effect of bodily illusions on corticomotoneuronal excitability was limited (only 14 experiments) and had a high risk of bias, kinaesthetic illusions and illusions of embodying a hand (and seeing it move), had consistent effects. Future investigations into the role of embodiment and the illusion strength on corticomotoneuronal excitability and inhibition are warranted.