Visual Afterimages Research Articles

An Au25 nanocluster/MoS2 vdWaals heterojunction phototransistor for chromamorphic visual-afterimage emulation.

Color vision relies on three cone photoreceptors that are sensitive to different wavelengths of light. The interaction of three incident light wavelengths over time creates a fascinating color coupling perception, termed chromamorphic computing. However, the realization of this fascinating characteristic in semiconductor devices remains a great challenge. Herein, a mixed-dimensional optoelectronic transistor based on a novel metal nanocluster Au25(SC12H25)18 and two-dimensional MoS2 van der Waals (vdWaals) heterojunction is proposed for chromamorphic visual-afterimage emulation with red-green-blue three-color spatiotemporal coupling perception. This distinguished molecular-like electronic level of Au25 nanoclusters allows the transistor to have visible light-sensitive properties, endowing it with the ability to perceive color information. Moreover, the chromamorphic functions are realized using a color spatiotemporal coupling approach. By utilizing the photogating effect of light stimulus, the device exhibits visual experience-dependent plasticity in accordance with the Bienenstock-Cooper-Munro (BCM) learning rule. Most importantly, for the first time, intriguing visual afterimages could be implemented using a color sensitization approach based on a close relationship between visual persistence and negative afterimages. These results represent an important step towards a new generation of intelligent visual color perception systems for human-computer interaction, bionic robots, etc.

Research on Visual Fatigue Caused by Color Combinations in Civil Aircraft Cockpit Display Interfaces

In order to analyze the visual fatigue degree of the foreground and background color combination of the display of civil aircraft cockpit, the visual afterimage experimental paradigm is used in the present study. Objective eye movement data and subjective reported visual afterimage color were collected. The difference of pupil diameter under different color combinations showed that background color had a significant effect on visual fatigue. In addition, black background color can lead to the lowest degree of visual fatigue, followed by brown background color. Moreover, blue background color was the most likely to cause visual fatigue. The subjective report data showed that the visual afterimage color was related to the foreground and background color combination. In the combination of background color and foreground color, the ratio of visual afterimage color and background color is the highest, followed by the foreground color, and the complementary color of foreground color or background color. Based on the above results, the color design suggestions of civil aircraft cockpit interface are proposed in this work.

Evidence of High-Detail Perceptual Modeling in the Visual Cortex

This informal but well-referenced description of an afterimage experiment called Ghost Tap provides persuasive and easily reproducible evidence that the visual cortex plays a significant role in certain classes of long-duration visual afterimages. Subjects of the experiment literally cannot discern the difference between the afterimage and reality, resulting in easy startling of the subjects when physical motion in the room no longer matches the persuasive afterimages they are perceiving. Anecdotal examples of less extreme versions of the same effect suggest that the Ghost Tap effect has, over centuries, intentionally and unintentionally helped persuade people of the existence of nominally “supernatural” effects that are just persuasive long-duration afterimages. While this description is informal, the easy reproducibility of the Ghost Tap makes it a good candidate for more precise and quantitative studies. One theory why Ghost Tap exists is that it is part of load reduction and speed enhancement strategy to compensate for the slow processing speeds of neurons. Maintaining a dynamic and predictive real-time model of likely sensory inputs from the external world would enable the brain to discard quickly and with minimal processing any sensory inputs that fall within the predictive tolerance limits to the current model state. A perceptive load reduction interpretation of the Ghost Tap argues that the ability of the brain to support dreaming in vivid detail is likely a direct corollary of its ability to create dream-like waking states for faster and more efficient processing of large sensory loads. If the brain regularly uses dream-like waking states to reduce data, more study of effects like Ghost Tap might help explain the frequency of pathologies in which perception becomes disconnected from reality.

Visual Characteristics of Afterimage under Dark Surround Conditions

Three psycho-visual experiments were carried out to investigate visual afterimage characteristics of high luminance LEDs under dark surround conditions. The results show that the luminance of illumination, exposure time and background luminance are the primary factors influencing the afterimage’s duration, the color difference between stimulus and background, and visibility. Besides, visual afterimage characteristics are strongly correlated with the luminance contrast between the stimulus and the background, but not for the color difference with a white background. A third-order polynomial regression model was proposed to accurately estimate the afterimage duration, the color difference between stimulus and background, and visibility. The model performance showed high R-squared, low root-mean-square error (RMSE) and mean absolute error (MAE) values between the predicted and visual characteristics.

Personality and opponent processes: Shyness, sociability, and visual afterimages to emotion.

The opponent process theory of emotion posits that emotional states evoke opposite emotion states as they wane, resulting in sequential approach and withdrawal motivations. However, whether opponent processes are associated with individual differences in personality remains an empirical question. Using visual afterimage responses to emotional faces as an index of opponent processes, we found that young adults (N = 101; Mage = 19.41 years, SD = 2.06 years) characterized by relatively high shyness and high sociability (i.e., conflicted shyness) were more likely to perceive a negative face emotion afterimage after adapting to happy faces and a positive face emotion afterimage after adapting to angry faces, compared with young adults classified by other combinations of high and low shyness and sociability. We speculate that conflicted shyness may result from strong opponent processes to both positive and negative emotions to real or anticipated social situations in some individuals, resulting in conflicting social motivations. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Illusory palinopsias induced by in vitro fertilization treatment: a case report

BackgroundIn the current era, in vitro fertilization, a type of assisted reproductive technology, has been commonly used for infertility management and gestational surrogacy. The techniques that are routinely used in in vitro fertilization include ovarian hyperstimulation to generate multiple eggs, preparation of the ova and sperm, and culture and selection of resultant embryos before transfer into a uterus. These steps increase the chances of successful pregnancy following in vitro fertilization treatment many-fold, especially in young women. Complications reported with in vitro fertilization treatment include multiple gestations, ovarian hyperstimulation syndrome, and birth defects while ocular side effects reported include retinal detachment and progression of keratoconus. We report a case of visual illusory palinopsia following in vitro fertilization treatment in a patient with unexplained infertility.Case presentationA 31-year-old Asian woman was administered in vitro fertilization treatment for her unexplained infertility. She complained of visually disturbing flashes in her peripheral vision during her pregnancy. She described these flashes as occurring usually in the morning hours or while walking, coming in sets of three to four, occurring five–six times a day and lasting for less than 5–10 minutes. Her flashes were not accompanied by other ocular symptoms such as pain, redness, photophobia, or decrease in vision. Her ocular examination was normal. Neuroimaging with magnetic resonance imaging revealed no pathology. A diagnosis of visual illusory palinopsia secondary to in vitro fertilization treatment was made.ConclusionDisturbing visual palinopsia and afterimages can occur following in vitro fertilization treatment for infertility due to increased estrogen levels. This rare ocular side effect caused by in vitro fertilization treatment is not reported in the literature to the best of our knowledge. Gynecologists and/or infertility experts should educate their patients regarding these possible ocular symptoms. Even ophthalmologists should be aware of this rare cause for visual palinopsia.

Reduced Fading of Visual Afterimages after Transcranial Magnetic Stimulation over Early Visual Cortex

In the complete absence of small transients in visual inputs (e.g., by experimentally stabilizing an image on the retina or in everyday life during intent staring), information perceived by the eyes will fade from the perceptual experience. Although the mechanisms of visual fading remain poorly understood, one possibility is that higher level brain regions actively suppress the stable visual signals via targeted feedback onto early visual cortex (EVC). Here, we used positive afterimages and multisensory conflict to induce gestalt-like fading of participants' own hands. In two separate experiments, participants rated the perceived quality of their hands both before and after transcranial magnetic stimulation (TMS) was applied over EVC. In a first experiment, triple-pulse TMS was able to make a faded hand appear less faded after the pulses were applied, compared with placebo pulses. A second experiment demonstrated that this was because triple-pulse TMS slowed down fading of the removed hand that otherwise occurs naturally over time. Interestingly, TMS similarly affected the left and right hands, despite being applied only over the right EVC. Together, our results suggest that TMS over EVC attenuates the effects of visual fading in positive afterimages, and it might do so by crossing transcollosal connections or via multimodal integration sites in which both hands are represented.

Supplemental Material for Retinal Spatiotemporal Dynamics on Emergence of Visual Persistence and Afterimages

Supplemental Material for Retinal Spatiotemporal Dynamics on Emergence of Visual Persistence and Afterimages

Re-examining the influence of attention and consciousness on visual afterimage duration.

The relationship between visual attention and conscious perception has been the subject of debate across a number of fields, including philosophy, psychology, and neuroscience. Whereas some researchers view attention and awareness as inextricably linked, others propose that the two are supported by distinct neural mechanisms that can be fully dissociated. In a pioneering study, van Boxtel, Tsuchiya, and Koch (2010b) reported evidence for a dissociation between attention and conscious perception using a perceptual adaptation task in which participants' perceptual awareness and visual attention were manipulated independently. They found that participants' awareness of an adapting stimulus increased afterimage duration, whereas attending to the adaptor decreased it. Given the important theoretical implications of these findings, we endeavored to replicate them using an identical paradigm while dealing with some potential shortcomings of the original study by adding more trials and a larger participant sample. Consistent with van Boxtel, Tsuchiya, and Koch, we found that afterimage duration was reliably increased when participants were aware of the adapting stimulus. In contrast to the original findings, however, attention to the adaptor also increased afterimage duration, suggesting that attention and awareness had the same-rather than opposing-effects on afterimage duration. We discuss possible reasons for this discrepancy. (PsycINFO Database Record

Clomiphene citrate-induced visual hallucinations: a case report

BackgroundPolycystic ovary syndrome is a common cause of chronic anovulation and infertility in otherwise healthy fertile couples. Clomiphene citrate is used as a first-line ovulation induction therapy in patients with polycystic ovary syndrome. Clomiphene citrate can cause both systemic and ocular side effects. We report a rare side effect of illusory palinopsias in a patient with polycystic ovary syndrome treated with ovulation induction therapy with clomiphene citrate, and emphasize the need for gynecologists and their patients to be aware of this rare ocular side effect.Case presentationA 30-year-old Asian woman complained of persistent visual afterimages following treatment with 100 mg clomiphene citrate for anovulation. Her symptoms started on the fourth day after commencing the treatment and would last for 5 to 10 minutes. Similar visual symptoms were noted during her second cycle of treatment with clomiphene citrate. The severity of her symptoms reduced following the stoppage of the medication; however, the symptoms have persisted for more than 1 year since she stopped taking the drug.ConclusionsClomiphene citrate can cause disturbing illusory palinopsias. These afterimages persist even after stopping the infertility medication. It is a side effect not frequently seen by gynecologists or ophthalmologists. Gynecologists should make their patients aware of this rare ocular side effect when their patients start treatment with clomiphene citrate for infertility.

Self-Grounded Vision: Hand Ownership Modulates Visual Location through Cortical β and γ Oscillations.

Vision is influenced by the body: in the Taylor illusion, the size of an afterimage projected on one's hand changes according to tactile and proprioceptive signals conveying hand position. Here, we report a new phenomenon revealing that the perception of afterimages depends not only on bodily signals, but also on the sense of self. Relying on the rubber hand illusion, we manipulated hand ownership, so that participants embodied a rubber hand placed next to their own hand. We found that visual afterimages projected on the participant's hand drifted laterally, only when the rubber hand was embodied. Electroencephalography revealed spectral dissociations between somatic and visual effects, and higher γ connectivity along the dorsal visual pathways when the rubber hand was embodied.

Multisensory Tracking of Objects in Darkness: Capture of Positive Afterimages by the Tactile and Proprioceptive Senses.

This paper reports on three experiments investigating the contribution of different sensory modalities to the tracking of objects moved in total darkness. Participants sitting in the dark were exposed to a brief, bright flash which reliably induced a positive visual afterimage of the scene so illuminated. If the participants subsequently move their hand in the darkness, the visual afterimage of that hand fades or disappears; this is presumably due to conflict between the illusory visual afterimage (of the hand in its original location) and other information (e.g., proprioceptive) from a general mechanism for tracking body parts. This afterimage disappearance effect also occurs for held objects which are moved in the dark, and some have argued that this represents a case of body schema extension, i.e. the rapid incorporation of held external objects into the body schema. We demonstrate that the phenomenon is not limited to held objects and occurs in conditions where incorporation into the body schema is unlikely. Instead, we propose that the disappearance of afterimages of objects moved in darkness comes from a general mechanism for object tracking which integrates input from multiple sensory systems. This mechanism need not be limited to tracking body parts, and thus we need not invoke body schema extension to explain the afterimage disappearance. In this series of experiments, we test whether auditory feedback of object movement can induce afterimage disappearance, demonstrate that the disappearance effect scales with the magnitude of proprioceptive feedback, and show that tactile feedback alone is sufficient for the effect. Together, these data demonstrate that the visual percept of a positive afterimage is constructed not just from visual input of the scene when light reaches the eyes, but in conjunction with input from multiple other senses.

A computational model of retinal circuitry predicts stimulus duration and intensity effects on visual persistence and afterimages

A computational model of retinal circuitry predicts stimulus duration and intensity effects on visual persistence and afterimages

Measuring palinopsia: Characteristics of a persevering visual sensation from cerebral pathology

Palinopsia is an abnormal perseverative visual phenomenon, whose relation to normal afterimages is unknown. We measured palinoptic positive visual afterimages in a patient with a cerebral lesion. Positive afterimages were confined to the left inferior quadrant, which allowed a comparison between afterimages in the intact and the affected part of his visual field. Results showed that negative afterimages in the affected quadrant were no different from those in the unaffected quadrant. The positive afterimage in his affected field, however, differed both qualitatively and quantitatively from normal afterimages, being weaker but much more persistent, and displaced from the location of the inducing stimulus. These findings reveal distinctions between pathological afterimages of cerebral origin and physiological afterimages of retinal origin.

Visual Afterimages of Emotional Faces in High Functioning Autism

Fixating an emotional facial expression can create afterimages, such that subsequent faces are seen as having the opposite expression of that fixated. Visual afterimages have been used to map the relationships among emotion categories, and this method was used here to compare ASD and matched control participants. Participants adapted to a facial expression for 45s then saw a neutral face for 800ms and chose a label to describe the latter. The ASD group showed evidence of afterimages, but atypical patterns of opposition: whereas fixating negative emotions uniformly evokes a positive afterimage in the control group, fixating negative emotions was more likely to evoke a negative afterimage in the ASD group. This study was the first to provide evidence of visual aftereffects in ASD and suggests a different psychological organization among emotions in those with ASD.

A Dissociation of Attention and Awareness in Phase-sensitive but Not Phase-insensitive Visual Channels

The elements most vivid in our conscious awareness are the ones to which we direct our attention. Scientific study confirms the impression of a close bond between selective attention and visual awareness, yet the nature of this association remains elusive. Using visual afterimages as an index, we investigate neural processing of stimuli as they enter awareness and as they become the object of attention. We find evidence of response enhancement accompanying both attention and awareness, both in the phase-sensitive neural channels characteristic of early processing stages and in the phase-insensitive channels typical of higher cortical areas. The effects of attention and awareness on phase-insensitive responses are positively correlated, but in the same experiments, we observe no correlation between the effects on phase-sensitive responses. This indicates independent signatures of attention and awareness in early visual areas yet a convergence of their effects at more advanced processing stages.

The role of selective visual attention in the formation of visual afterimages: Experimental data and model simulations

The role of selective visual attention in the formation of visual afterimages: Experimental data and model simulations

Discussion on Colour Design of Medical Product Based on Visual Negative Afterimage Theory

This paper mainly analyses and discusses the application and significance of the visual negative afterimage on the colour design of medical product based on the visual negative afterimage theory. The design for the colour of medical product based on the visual negative afterimage theory focuses more human orientation in aspect of the visual effect design. The paper also points out that the trend of future design is to organically combine the art, the therapy features and the humanity.The complementary colour equilibrium of the visual negative afterimage will play a more and more important role in the colour design of the medical product. In the modern medical environment, the colour of the medical product has a decisive effect on the information exchange between people and the space environment. Although the visual negative afterimage is common in our daily life, the colour is not taken into consideration in the colour design of the medical product, which will result in negative effects. The colour is a strong and extremely attractive expression tool. Therefore, when the colour is designed for the medical product, it should be applied reasonably. The application of colour must be based on the special function requirements and the use of different people, so as to show its special function and requirements, which not only avoids the negative influence caused by the visual negative afterimage, but also creates a more humanistic atmosphere for the medical environment.

Modeling filling-in of afterimages

Van Lier, Vergeer, and Anstis (2009) reported that color information in a visual afterimage could spread across regions that were not colored in the inducing stimulus. The perceived color and shape of the afterimage could be manipulated by drawn contours that apparently trap the spread of afterimage color signals. They further hypothesized that the observed effects indicated a common mechanism for afterimage color filling-in and real-color filling-in phenomena. New simulations of the existing boundary contour system/feature contour system model of visual perception (Grossberg & Mingolla, 1985a, 1985b) demonstrate the connection between these phenomena.

Being in the dark about your hand: Resolution of visuo-proprioceptive conflict by disowning visible limbs

Conflict between sensory modalities can be resolved by one modality overwriting another. For example, movement of a limb that is visible in a stationary visual afterimage results in selective fading of that limb in the afterimage. We investigated the interaction of these two sensory modalities by inducing a mismatch between visual and proprioceptive hand location. Whereas this discrepancy did not affect the initial appearance of the hand in the afterimage, it did prevent subsequent motion with the hand from affecting the hand's appearance. Location mismatch disconnected the visual and proprioceptive experiences of the hand, "protecting" the visual afterimage from interaction with proprioception. Investigation of subjective higher order bodily experiences showed a strong negative correlation between afterimage disruption and the subjective feeling of ownership, suggesting that the brain can resolve multimodal location mismatch by 'disowning' a visible limb, and that the interaction between proprioception and vision is mediated by higher order bodily experiences.