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Rate control is an important technique for practical video coding applications by allocating suitable quantization parameters (QPs) for CTUs or frames to satisfy bandwidth requirement. However, rate control may result in video quality fluctuation because neighboring regions are quantized into different quality levels, which may affect viewing experience seriously, especially at low bitrate scenarios. In this paper, we propose a novel CTU (Coding Tree Unit) level rate control approach for intra frame of the high efficiency video coding (HEVC) standard with consistent perceptual quality. In particular, a new perceptual hyperbolic rate distortion (R-D) optimization method is proposed for rate control with the constraint of constant perceptual quality, which shows good compatibility with other R-D models. Herein, a novel CTU level perceptual distortion model is presented to achieve the optimal rate control of intra frames for HEVC, where the Lagrange multiplier is adjusted by taking advantage of the different perceptual characteristics to achieve the minimal perceptual distortion variation across CTUs within one frame. Extensive experiments prove that the proposed algorithm outperforms the state-of-the-art CTU level rate control methods by considering R-D performance. In addition, subjective simulation results demonstrate that our algorithm further improves the visual quality of compressed videos by reducing perceptual quality fluctuation.

The self-image is a term that refers to the actions of the human being where he tries and reaches to develop ideas, thoughts, emotions, perceptions and visions of himself. The objective of the study was to evaluate the anthropometric nutritional assessment and the self-perception of body image of adolescents in the Pillaro canton, using a methodology with a non-experimental design, a correlational cross-section in which we worked with a sample of 245 participants (57.1% women and 42.9% women). .% males) ranging in age from 10 to 20 years of age who completed online surveys of the Body Shape Questionnaire (BSQ), the Eating Attitudes Test (EAT-26) and the Body Mass Index (IMC), obtaining results from the completed surveys, where it is indicated that 38.8% of adolescents do not feel concern about body image, 61.2% did not show risk in the variable related to eating disorders, it was also found that in the population of Pillaro there is no degree of disparity between the perception of the body self-image versus the reality of the individual, however it was observed that women predominate These distortions differ significantly from men, therefore, factors such as age, sex and social environment are highly related to self-perception, triggering eating disorders, psychological and physical disorders; Based on what was previously mentioned, the resolution is reached that body image has a very close relationship with the eating disorders that adolescents currently suffer, depending on the place where the adolescent population is located, affirming the hypothesis raised at the beginning. Of the investigation. La autoimagen es un término que denomina el accionar del ser humano donde este pretende y alcanza a desarrollar ideas, pensamientos, emociones, percepciones y visiones de sí mismo. El objetivo del estudio ha evaluar la valoración nutricional antropométrica y la autopercepción de imagen corporal de adolescentes del cantón Pillaro, utilizando una metodología con diseño no experimental, corte transversal correlacional en la cual se trabajó con una muestra de 245 participantes (57.1 % mujeres y 42.9.% varones) abarcando edades de entre los 10 y 20 años de edad que llenaron encuestas de forma virtual de Body Shape Questionnaire (BSQ), el Test De Actitudes Alimentarias (EAT-26) y el Índice de Masa Corporal (IMC), obteniéndose resultados a partir de las encuestan llenadas, en donde se indica que el 38.8% de adolescentes no sienten preocupación por la imagen corporal, el 61.2% no mostró riesgo en la variable relacionada con trastornos alimentarios, se constató además, que en la población de Pillaro no existe un grado de disparidad entre la percepción del autoimagen corporal versus la realidad del individuo, sin embargo si se visualizó que en las mujeres predominan mayoritariamente estas distorsiones que en los hombres, por lo tanto, factores como edad, sexo y medio social están altamente relacionados con la autopercepción, desencadenando trastornos alimentarios, trastornos psicológicos y físicos; en base a lo mencionado previamente, se llega a la resolución de que la imagen corporal lleva una relación ínfimamente estrecha con los trastornos de alimentación que padecen los adolescentes en la actualidad dependiendo del lugar donde la población adolescente se encuentre, afirmándose la hipótesis planteada al inicio de la investigación. A autoimagem é um termo que se refere às ações do ser humano onde ele tenta e chega a desenvolver ideias, pensamentos, emoções, percepções e visões de si mesmo. O objetivo do estudo foi avaliar a avaliação nutricional antropométrica e a autopercepção da imagem corporal de adolescentes do cantão de Pillaro, por meio de uma metodologia com desenho não experimental, um corte transversal correlacional em que trabalhamos com uma amostra de 245 participantes (57,1% mulheres e 42,9% mulheres). .% homens) com idades entre 10 e 20 anos que completaram pesquisas online do Body Shape Questionnaire (BSQ), do Eating Attitudes Test (EAT-26) e do Índice de Massa Corporal (IMC), obtendo resultados dos inquéritos preenchidos, onde se indica que 38,8% dos adolescentes não sentem preocupação com a imagem corporal, 61,2% não apresentaram risco na variável relacionada com os transtornos alimentares, constatou-se também que na população de Pillaro não há grau de disparidade entre a percepção da autoimagem corporal versus a realidade do indivíduo, porém observou-se que predominam as mulheres Essas distorções diferem significativamente dos homens, portanto, fatores como idade, sexo e ambiente social estão altamente relacionados à autopercepção, desencadeando transtornos alimentares, psicológicos e físicos; Com base no que foi mencionado anteriormente, chega-se à conclusão de que a imagem corporal tem uma relação muito estreita com os transtornos alimentares que os adolescentes sofrem atualmente, dependendo do local onde a população adolescente está localizada, afirmando a hipótese levantada no início.

Age-related hearing loss (ARHL) is a devastating public health issue. To successfully address ARHL using existing and future treatments, it is imperative to detect the earliest signs of age-related auditory decline and understand the mechanisms driving it. Here, we explore early signs of age-related auditory decline by characterizing cochlear function in 199 ears aged 10–65 years, all of which had clinically defined normal hearing (i.e., behavioral thresholds ≤ 25 dB HL from .25 to 8 kHz bilaterally) and no history of noise exposure. We characterized cochlear function by measuring behavioral thresholds in two paradigms (traditional audiometric thresholds from .25 to 8 kHz and Békésy tracking thresholds from .125 to 20 kHz) and distortion product otoacoustic emission (DPOAE) growth functions at f(2) = 2, 4, and 8 kHz. Behavioral thresholds through a standard clinical frequency range (up to 8 kHz) showed statistically, but not clinically, significant declines across increasing decades of life. In contrast, DPOAE growth measured in the same frequency range showed clear declines as early 30 years of age, particularly across moderate stimulus levels (L(2) = 25–45 dB SPL). These substantial declines in DPOAE growth were not fully explained by differences in behavioral thresholds measured in the same frequency region. Additionally, high-frequency Békésy tracking thresholds above ~11.2 kHz showed frank declines with increasing age. Collectively, these results suggest that early age-related cochlear decline (1) begins as early as the third or fourth decade of life, (2) is greatest in the cochlear base but apparent through the length of the cochlear partition, (3) cannot be detected fully by traditional clinical measures, and (4) is likely due to a complex mix of etiologies.

Mechanoreceptors on the skin are heterogeneously distributed, and the sampling of neural signals in the brain can vary depending on the part of the body. Therefore, it can be challenging for the brain to consistently represent stimuli applied to different body sites. Here, we report an example of a regional perceptual distortion of the tactile space. We used a piezoelectric braille display to examine shape perception on the volar surface of the arm and to compare it to that on the palm. We found that the orientation of perceived stimuli on the arm was distorted in certain areas. In particular, an inwardly-inclined line shape was perceived as being more inwardly-inclined than it actually was. On the other hand, an outwardly-inclined line was perceived accurately. When the same stimuli were applied to the palm, this anisotropic bias was not observed. We also found that changing the posture of the arm changed the angle at which this anisotropic distortion occurred, suggesting the influence of the skin frame of reference on this illusion. This study showed a clear example of how the representation of even simple stimuli is complexly distinct when the stimuli are applied to different body sites.

Orofacial pain patients often report that the painful facial area is "swollen" without clinical signs - known as perceptual distortion (PD). The neuromodulatory effect of facilitatory repetitive transcranial magnetic stimulation (rTMS) on PD in healthy individuals was investigated, to provide further support that the primary somatosensory cortex (SI) is involved in facial PD. Participants were allocated to active (n = 26) or sham (n = 26) rTMS group in this case-control study. PD was induced experimentally by injecting local anesthesia (LA) in the right infraorbital region. PD was measured at baseline, 6 min after LA, immediately, 20 and 40 min after rTMS. Intermittent theta-burst stimulation (iTBS) as active rTMS and sham rTMS was applied to the face representation area of SI at 10 min after LA. The magnitude of PD was compared between the groups. The magnitude of PD significantly increased immediately after iTBS compared with sham rTMS (P = .009). The PD was significantly higher immediately after iTBS compared to 6 min after LA (P = .004) in the active rTMS group, but not in the sham rTMS group (P = .054). iTBS applied to a somatotopic-relevant cortical region appears to facilitate facial PD further supporting the involvement of SI in the processing of one´s own face and PD. PERSPECTIVE: This study provides information on neural substrate responsible for processing of perceptual distortion of the face which is speculated to contribute to the chronification of orofacial pain. The findings of this study may aid in mechanism-based management of the condition in orofacial pain disorders and possibly other chronic pain states.

What is it like to perceive a feared object? According to a popular neo-Gibsonian theory in psychology, fear biases our perceptions of objects so as to encourage particular kinds of actions: when we are afraid, spiders may be perceived as physically closer than they are in order to promote fleeing. Firestone mounted severe criticisms against this view, arguing that these cases are better explained by non-perceptual biases that operate on accurate perceptions of the external environment. In this paper I will argue that fear might indeed distort our perceptions of the world, but not in the way neo-Gibsonians suppose. In the view I favor, perceptual distortions occur as by-products of fearful attention, a special mode of attention that is part of an orchestrated defensive response that prepares the organism to deal effectively with a threat. To argue for this view I will rely on empirical evidence that fearful attention narrows down the focus of attention and favors processing of local rather than global features of stimuli, which may jointly explain why perceptual distortions might occur in fearful object seeing. This view has consequences not only for empirical investigations in fearful perceptual distortions, but also for an explanation of the intentionality of fear and the phenomenal integration of bodily and intentional elements in fear episodes.

Studies suggest looming motion represents a special class of attentional capture stimulus due to behavioral urgency: the need to act upon objects moving toward us in an environment. In particular, one theory suggests that faster reaction times to targets cued by looming relative to receding motion are driven by post-attentional, motor-priming processes beyond the attentional capture effects seen with other stimulus qualities such as color pop-out. The present study tested this theory using a relative size judgment task where targets were pre-cued by looming and receding optic flow fields. Results show systematic increases in the perceived size of targets that were cued by looming flow fields, consistent with previous attentional capture studies using onset cues. These results challenge theories attributing behavioral changes from looming motion to motor-priming alone.

The process of rate-distortion (RD) optimization plays a key role for video coding, which aims to achieve a tradeoff between compression efficiency and video quality distortion. Although the conventional objective distortion metric mean squared error performs well in computational complexity, it is not always in accordance with the perceptual quality perceived by human visual system (HVS). Taking the characteristics of HVS into consideration, a perceptually weighted mean squared error (PWMSE) based RD model is proposed in this work. First, a low-pass filter is employed to process the original distortion information in order to simulate visual signal processing and obtain the perceptual distortion. Then, masking modulation in both temporal and spatial domains is introduced into distortion model, and a novel Lagrange multiplier is derived accordingly. The proposed PWMSE based RD model is applied to the high efficiency video coding standard, and comparative experimental results demonstrate its effectiveness. The project page can be found in https://mic.tongji.edu.cn/ab/40/c9778a174912/page.htm .

Humans interact in groups through various perception and action channels. The continuity of interaction despite a transient loss of perceptual contact often exists and contributes to goal achievement. Here, we study the dynamics of this continuity, in two experiments involving groups of participants (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$N=7$$\end{document}N=7) synchronizing their movements in space and in time. We show that behavioural unison can be maintained after perceptual contact has been lost, for about 7s. Agent similarity and spatial configuration in the group modulated synchronization performance, differently so when perceptual interaction was present or when it was memorized. Modelling these data through a network of oscillators enabled us to clarify the double origin of this memory effect, of individual and social nature. These results shed new light into why humans continue to move in unison after perceptual interruption, and are consequential for a wide variety of applications at work, in art and in sport.

Background Increasing interest in appearance and the growing preference for a beautiful body can lead to physical and psychological problems due to an inappropriate body image perception. As such, there is a need to identify what factors may contribute to an inappropriate body image. The purpose of this study was to examine the presence of distorted body weight perception among middle-aged Koreans and identify gender differences and other factors that contribute to a distorted body image regarding body weight. Methods Data on 8363 middle-aged adults (aged 45–64 years) from the Korea National Health and Nutrition Examination Survey were analyzed using complex samples analysis considering weight, stratification variables, and cluster variables. The difference between perceived body image regarding body weight and actual body mass index was used to assess distorted body weight perception. Socioeconomic status, health behaviors, daily energy consumption, and psychological status (depression and stress) were assessed for their relationship to distorted body weight perception. Results Results showed that a distorted body image regarding body weight was more prevalent among middle-aged men (45.3%) than women (25.7%). Age, income, perceived health status, and health behaviors were significantly associated with distorted body weight perception in middle-aged men, whereas psychological factors were associated with distorted body weight perception in middle-aged women. Conclusions Further research on distorted body weight perception is needed to gain understanding of the gender differences between middle-aged men and women in Korea. Furthermore, to the results of the study can be used as a basis for developing various education, health mediation, and public health promotion interventions and programs to address body weight perception in middle-aged adults.

In virtual reality (VR), how to map large-scale virtual spaces to small tracking area is a challenging problem. In this paper, we propose a novel steering algorithm for the redirected walking (RDW) technique to steer users away from the boundaries of the tracking area while reducing perceptible discrepancies. Inspired by the motion illusion that when a person is blindfolded, she goes in circles while thinking she is walking in a straight and infinitely long path, we map the path composed of straight-line segments in virtual space to a path composed of arcs in real space, and use one-step-ahead strategy and a buffer zone to reduce the number of user-boundary collisions. To verify the effectiveness of our algorithm, we conduct two experiments based on simulated in large-scale virtual spaces with a relatively small tracking area. The results indicate that our algorithm can effectively reduce collisions and perceptual distortion, and show the potential to address the challenge of simultaneously redirecting more than one user.

Many people who have undergone Anterior Cruciate Ligament (ACL)-reconstruction do not return to their pre-injury level, with nonphysical factors recognized as barriers to recovery. Fear of movement has been linked to body schema distortions, and interventions directed at the body schema have shown potential to improve function. 1) Describe participants’ ability to perform a visual imagery intervention (Body Scan); 2) investigate knee perception differences; 3) investigate if Body Scan led to improvements in perceptual differences; and 4) determine if some individuals improved in functional measures following the intervention. A single-arm intervention study was undertaken in people >12-month post ACL-reconstruction (n = 30). Body Scan was delivered using a standardized script developed for this study. Participants were assessed regarding their capacity to perform the Body Scan, perceptual differences between the knees and how perception changed following the intervention. Functional measures (vertical hop, triple hop, mSEBT, quadriceps strength, and hamstring strength) were taken. 96.7% were able to perform a Body Scan, with 93.1% demonstrating a difference in perception between the knees. Of participants with perceptual differences, 92.5% demonstrated improvement in perception following the intervention. Ten participants had a clinically significant improvement in a functional measure following the intervention. Most participants could perform Body Scanning. The majority perceived perceptual differences between operated and non-operated knees, and reported more symmetric perception following the intervention. One-third of participants also showed improvements in a functional performance measure. Results suggest this intervention may be a helpful adjunct to rehabilitation post ACL-reconstruction, with further research warranted.

We live in a dynamic, distracting world. When distracting information captures attention, what are the consequences for perception? Previous literature has focused on effects such as reaction time (RT) slowing, accuracy decrements, and oculomotor capture by distractors. In the current study, we asked whether attentional capture by distractors can also more fundamentally alter target feature representations, and if so, whether participants are aware of such errors. Using a continuous report task and novel confidence range report paradigm, we discovered 2 types of feature-binding errors when a distractor was presented along with the target: First, when attention is strongly captured by the distractor, participants commit swapping errors (misreporting the color at the distractor location instead of the target color), which remarkably seem to occur without awareness. Second, when participants successfully resist capture, they tend to exhibit repulsion (perceptual distortion away from the color at the distractor location). Thus, we found that capture not only induces a spatial shift of attention, it also alters feature perception in striking ways. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

A violência sexual infantil pode gerar graves prejuízos para o desenvolvimento psicossocial de suas vítimas. As avaliações nesse contexto requerem o uso de vários testes psicológicos que possuem evidências de validade para este fim. Este estudo teve como objetivo avaliar crianças vítimas de violência sexual com o Zulliger aplicação R-Otimizada. A amostra consistiu em 37 crianças com idade entre 7 e 13 anos (M = 10,92), de ambos os sexos, distribuídas em três grupos: Vítimas de Violência Sexual (VVS), Pacientes com Câncer (PC) e Grupo de Não-Vítimas (GNV). Realizou-se tratamento estatístico por meio dos testes Mann-Whiney e Anova de uma via. Variáveis do Zulliger concernentes aos agrupamentos de Relacionamento Interpessoal (GHR, PHR, GHR:PHR, p), Autoimagem (MOR) e Processamento (W:M) apresentaram diferenças estatísticas quando o grupo VVS foi comparado aos outros grupos. O Zulliger aplicação R-Otimizada apresenta resultados promissores na avaliação de crianças VVS, indicando sua utilidade em avaliações desse contexto. La violencia sexual infantil puede causar daños al desarrollo psicosocial de las víctimas. Evaluaciones en este contexto requieren uso de exámenes psicológicos que tienen evidencia de validez para este propósito. Este estudio tuvo como objetivo evaluar niños víctimas de violencia sexual con lo Zulliger aplicación R-Optimizada. La muestra consistió en 37 niños de 7 a 13 años (M = 10.92), ambos sexos, distribuidos en tres grupos: Víctimas de Violencia Sexual (VVS), Pacientes con Cáncer (PC) y Grupo de No-Víctimas (GNV). El tratamiento estadístico se realizó utilizando las pruebas de Mann-Whiney y Anova de una vía. Variables de Zulliger para las agrupaciones de Relaciones Interpersonales (GHR, PHR, GHR:PHR, p), Autoimagen (MOR) y Procesamiento (W:M) mostraron diferencias estadísticas cuando el grupo VVS se comparó con los otros grupos. Zulliger aplicación R-Optimizada muestra resultados prometedores en la evaluación de niños VVS que indican su usabilidad en las evaluaciones en este contexto. Child sexual violence can cause serious damage to the psychosocial development of its victims. Assessments in this context require the use of several psychological tests with proven validity for this purpose. This study aimed to assess children victims of sexual violence using the Zulliger R-Optimized application. The sample consisted of 37 children of both sexes, aged from seven to 13 years old (M = 10.92), distributed in three groups: Sexual Violence Victims (SVV), Cancer Patients (CP) and the Non-Victim Group (NVG). The statistical analyses were performed using the Mann-Whiney and one-way ANOVA tests. The Zulliger variables concerning the clusters Interpersonal Relationship (GHR, PHR, GHR:PHR, p), Self-Image (MOR) and Processing (W:M) showed statistical differences when the SVV group was compared to the other groups. The Zulliger R-Optimized application shows promising results in assessing SVV children, indicating its usefulness for assessments in this context.

Hallucinatory experiences (HEs) can be pronounced in psychosis, but similar experiences also occur in nonclinical populations. Cognitive mechanisms hypothesized to underpin HEs include dysfunctional source monitoring, heightened signal detection, and impaired attentional processes. Using data from an international multisite study on non-clinical participants (N = 419), we described the overlap between two sets of variables - one measuring cognition and the other HEs - at the level of individual items. We used a three-step method to extract and examine item-specific signal, which is typically obscured when summary scores are analyzed using traditional methodologies. The three-step method involved: (1) constraining variance in cognition variables to that which is predictable from HE variables, followed by dimension reduction, (2) determining reliable HE items using split-halves and permutation tests, and (3) selecting cognition items for interpretation using a leave-one-out procedure followed by repetition of Steps 1 and 2. The results showed that the overlap between HEs and cognition variables can be conceptualized as bi-dimensional, with two distinct mechanisms emerging as candidates for separate pathways to the development of HEs: HEs involving perceptual distortions on one hand (including voices), underpinned by a low threshold for signal detection in cognition, and HEs involving sensory overload on the other hand, underpinned by reduced laterality in cognition. We propose that these two dimensions of HEs involving distortions/liberal signal detection, and sensation overload/reduced laterality may map onto psychosis-spectrum and dissociation-spectrum anomalous experiences, respectively. publishedVersion

Child sexual violence can cause serious damage to the psychosocial development of its victims. Assessments in this context require the use of several psychological tests with proven validity for this purpose. This study aimed to assess children victims of sexual violence using the Zulliger R-Optimized application. The sample consisted of 37 children of both sexes, aged from seven to 13 years old (M = 10.92), distributed in three groups: Sexual Violence Victims (SVV), Cancer Patients (CP) and the Non-Victim Group (NVG). The statistical analyses were performed using the Mann-Whiney and one-way ANOVA tests. The Zulliger variables concerning the clusters Interpersonal Relationship (GHR, PHR, GHR:PHR, p), Self-Image (MOR) and Processing (W:M) showed statistical differences when the SVV group was compared to the other groups. The Zulliger R-Optimized application shows promising results in assessing SVV children, indicating its usefulness for assessments in this context. Resumo A violência sexual infantil pode gerar graves prejuízos para o desenvolvimento psicossocial de suas vítimas. As avaliações nesse contexto requerem o uso de vários testes psicológicos que possuem evidências de validade para este fim. Este estudo teve como objetivo avaliar crianças vítimas de violência sexual com o Zulliger aplicação R-Otimizada. A amostra consistiu em 37 crianças com idade entre 7 e 13 anos (M = 10,92), de ambos os sexos, distribuídas em três grupos: Vítimas de Violência Sexual (VVS), Pacientes com Câncer (PC) e Grupo de Não-Vítimas (GNV). Realizou-se tratamento estatístico por meio dos testes Mann-Whiney e Anova de uma via. Variáveis do Zulliger concernentes aos agrupamentos de Relacionamento Interpessoal (GHR, PHR, GHR:PHR, p), Autoimagem (MOR) e Processamento (W:M) apresentaram diferenças estatísticas quando o grupo VVS foi comparado aos outros grupos. O Zulliger aplicação R-Otimizada apresenta resultados promissores na avaliação de crianças VVS, indicando sua utilidade em avaliações desse contexto. Resumen La violencia sexual infantil puede causar daños al desarrollo psicosocial de las víctimas. Evaluaciones en este contexto requieren uso de exámenes psicológicos que tienen evidencia de validez para este propósito. Este estudio tuvo como objetivo evaluar niños víctimas de violencia sexual con lo Zulliger aplicación R-Optimizada. La muestra consistió en 37 niños de 7 a 13 años (M = 10.92), ambos sexos, distribuidos en tres grupos: Víctimas de Violencia Sexual (VVS), Pacientes con Cáncer (PC) y Grupo de No-Víctimas (GNV). El tratamiento estadístico se realizó utilizando las pruebas de Mann-Whiney y Anova de una vía. Variables de Zulliger para las agrupaciones de Relaciones Interpersonales (GHR, PHR, GHR:PHR, p), Autoimagen (MOR) y Procesamiento (W:M) mostraron diferencias estadísticas cuando el grupo VVS se comparó con los otros grupos. Zulliger aplicación R-Optimizada muestra resultados prometedores en la evaluación de niños VVS que indican su usabilidad en las evaluaciones en este contexto.

Hallucinogen-persisting perception disorder (HPPD) features as a diagnostic category in the DSM-5, ICD-11, and other major classifications, but our knowledge of the phenomenology of the perceptual symptoms involved and the changes in consciousness during the characteristic “flashbacks” is limited. We systematically evaluated original case reports and case series on HPPD to define its phenomenology, associated (psycho)pathology, and course. Our search of PubMed and Embase yielded 66 relevant publications that described 97 people who, together, experienced 64 unique symptoms of HPPD. Of these, 76% concerned symptoms characteristic of Alice in Wonderland syndrome, over 50% non-visual symptoms, and 38% perceptual symptoms not clearly linked to prior intoxication states. This is in contrast with the DSM-5 diagnostic criteria for HPPD. Even though less than half of the patients showed a protracted disease course of over a year, a third achieved remission. However, in patients with co-occurring depression (with or without anxiety) HPPD symptoms persisted longer and treatment outcomes were more often negative. Thus, unlike the acute stages of psychedelic drug intoxication, which may be accompanied by altered states of consciousness, HPPD is rather characterized by changes in the content of consciousness and an attentional shift from exogenous to endogenous phenomena. Since HPPD is a more encompassing nosological entity than suggested in the DSM-5, we recommend expanding its diagnostic criteria. In addition, we make recommendations for clinical practice and future research.

Aim: Body awareness arises when attending to and maintaining awareness of visuospatial body representations. By the same token, focussing on representations transfers them to working memory. Body awareness and working memory seemingly rely on similar processes and recruit common parietal areas involved in perception. Therefore, we asked whether visuospatial working memory abilities would define individual differences in the perception of spontaneous sensations (SPS), i.e., bodily sensations perceived in the absence of triggers (e.g., tactile stimulation or movement), when attending to the body.Method: Participants completed two visuospatial working memory tasks to assess various mechanisms: (i) the decay of representations was assessed through a Brown-Peterson task in which the delay between the memorandum presentation and its recall was manipulated, and (ii) the impact of distractors' interference and cognitive load (i.e., complexity) on recall performances were assessed through a complex span task that required the processing of distractors while maintaining a memorandum. A standard SPS task involving localization and characterization of SPS perceived on the hands was completed afterwards.Results: Low performance due to decay, distractors' interference and cognitive load in visuospatial working memory was associated with a decrease in the frequency of SPS. Additionally, low performance due to distractors' cognitive load predicted a decrease in the perception of surface-type sensations, and high performance despite distractors' interference led to a better perception of SPS on less sensitive areas of the hand.Conclusion: We discuss how visuospatial working memory processes might contribute to body awareness and perceptual distortions of the body.

Boundary samples are special inputs to artificial neural networks crafted to identify the execution environment used for inference by the resulting output label. The paper presents and evaluates algorithms to generate transparent boundary samples. Transparency refers to a small perceptual distortion of the host signal (i.e., a natural input sample). For two established image classifiers, ResNet on FMNIST and CIFAR10, we show that it is possible to generate sets of boundary samples which can identify any of four tested microarchitectures. These sets can be built to not contain any sample with a worse peak signal-to-noise ratio than 70dB. We analyze the relationship between search complexity and resulting transparency., Will be presented at IH&MMSEC '21

We propose a multi-task learning neural network for No-Reference image quality assessment (NR-IQA). The pro-posed architecture consists of a backbone feature extractor, a nested multi-task generative module and a quality regression module. We adopt a coarse-to-fine strategy to predict objective error maps in two subtasks optimized with different loss functions. The network is designed to be nested such that discriminative features learned from subtasks are efficiently shared by the primary task. Perceptual distortion maps are achieved by applying masking mechanism between reconstructed error maps and the learned distortion sensitivity map. At last, a quality regression module is adopted to nonlinearly map masked distortions to the subjective score. Experimental results demonstrate the superior performances of the proposed model over state-of-the-art models. The implementation of our method is released at https://github.com/R-JunmingChen/NEMG-IQA.

Background Voluntary movement such as lifting a foot in preparation to stepping acts as a self-initiated perturbation that disturbs postural equilibrium. To maintain and restore equilibrium, humans utilize early, anticipatory, and compensatory postural adjustments. Despite technological progress in accessible virtual reality (VR) devices, little is known on the usage of VR in control and maintenance of balance while standing. Research question How does VR modulate early, anticipatory, and compensatory postural adjustments during a dynamic task of leg lifting while avoiding an obstacle? Methods First, the postural adjustments in a single-leg obstacle avoidance were compared between real and VR settings, where a statistical reanalysis was performed with data subsets that minimize the difference of foot elevation speed. Second, the effect of simple foot elevation was examined to identify the fundamental nature of leg lifting motion as a self-initiated perturbation. Lastly, perceptual distortion in VR was assessed by evaluating how the spatial scale of the virtual scene used in the single-leg obstacle avoidance experiment was recognized by participants. Results The VR setting reduced the activities of lower leg muscles on the supporting side not only in the compensatory phase but also in the preparatory early and anticipatory phases. On the other hand, simple foot elevation resulted in a significant increase of muscle activities with lifting height only found in the compensatory phase. Furthermore, it is suggested that the VR induced perceptual distortion in estimating the sizes of the virtual objects. Significance The findings provide more definitive evidence that VR presentation modulates the components of postural adjustments for maintaining upright stance while being perturbed. One of the potential psychophysical factors is perceptual distortion in VR, and this provides critical information for further development of VR based training system.

No-reference (NR) perceptual video quality assessment (VQA) is a complex, unsolved, and important problem for social and streaming media applications. Efficient and accurate video quality predictors are needed to monitor and guide the processing of billions of shared, often imperfect, user-generated content (UGC). Unfortunately, current NR models are limited in their prediction capabilities on real-world, "in-the-wild" UGC video data. To advance progress on this problem, we created the largest (by far) subjective video quality dataset, containing 38,811 real-world distorted videos and 116,433 space-time localized video patches (‘v-patches’), and 5.5M human perceptual quality annotations. Using this, we created two unique NR-VQA models: (a) a local-to-global region-based NR VQA architecture (called PVQ) that learns to predict global video quality and achieves state-of-the-art performance on 3 UGC datasets, and (b) a first-of-a-kind space-time video quality mapping engine (called PVQ Mapper) that helps localize and visualize perceptual distortions in space and time. The entire dataset and prediction models are freely available at https://live.ece.utexas.edu/research.php.

Of the perceptual distortions characteristic of Alice in Wonderland syndrome, substantial alterations in the immediate experience of time are probably the least known and the most fascinating. We reviewed original case reports to examine the phenomenology and associated pathology of these time distortions in this syndrome. A systematic search in PubMed, Ovid Medline, and the historical literature yielded 59 publications that described 168 people experiencing time distortions, including 84 detailed individual case reports. We distinguished five different types of time distortion. The most common category comprises slow-motion and quick-motion phenomena. In 39% of all cases, time distortions were unimodal in nature, while in 61% there was additional involvement of the visual (49%), kinaesthetic (18%), and auditory modalities (14%). In all, 40% of all time distortions described were bimodal in nature and 19% trimodal, with 1% involving four modalities. Underlying neurological mechanisms are varied and may be triggered by intoxications, infectious diseases, metabolic disorders, CNS lesions, paroxysmal neurological disorders, and psychiatric disorders. Bizarre sensations of time alteration—such as time going backwards or moving in circles—were mostly associated with psychosis. Pathophysiologically, mainly occipital areas appear to be involved, although the temporal network is widely disseminated, with separate component timing mechanisms not always functioning synchronously, thus occasionally creating temporal mismatches within and across sensory modalities (desynchronization). Based on our findings, we propose a classification of time distortions and formulate implications for research and clinical practice.

Most current audio steganographic methods are content non-adaptive which have poor security and low embedding capacity. This paper proposes a generalized adaptive Huffman code mapping (AHCM) framework for obtaining higher secure payload. To avoid the frame-offset effect of audio codec, we first establish a distortion-limited suppressible code space, which realizes data embedding by using equal-length entropy codes. Furthermore, a stego key is used to dynamically build Huffman code mapping of each frame for improving acoustic imperceptibility and statistical undetectability. We then consider integrating psychoacoustic model (PAM) of intra-frame with frame-level perceptual distortion of inter-frame to obtain minimized total distortion. Finally, we present an implementation of the proposed AHCM framework on MP3 audios. A distortion function based on the PAM and an optimal steganographic frame path are, respectively, devised for adaptively embedding via employing syndrome-trellis codes. Experimental results demonstrate that our approach is, indeed, able to achieve higher secure steganographic capacity and better acoustic concealment. The detection accuracy of 320-kbps-mp3 datasets is lower than 65% when the embedding payload reaches 11 kbps, which is decreased by 11.8%–13.4% than the state-of-the-art steganographic methods.

BACKGROUND A recent study has shown variability on the perception of verticality during unilateral centrifugation among patients with type 2 diabetes mellitus; it is yet unknown if it is related to symptoms of unreality. OBJECTIVE In patients with type 2 diabetes mellitus compared to age matched healthy volunteers, to assess depersonalization/derealization (DD) symptoms before and after unilateral centrifugation, according to the subjective visual vertical (SVV). METHODS 47 patients with type 2 diabetes mellitus and 50 age matched healthy volunteers participated in the study. They replied to standardized questionnaires of symptoms related to balance, depression, and anxiety. Then, after neuro-otological evaluation, they completed a DD inventory before and after unilateral centrifugation (300°/s, 3.85 cm) with SVV estimation. RESULTS Right/left asymmetric SVV during centrifugation was identified in 17 patients (36%) and no SVV change during centrifugation was identified in 6 patients (13%). Before centrifugation, patients with asymmetric SVV already reported some of the DD symptoms, while patients with no SVV change reported almost no DD symptoms. Unilateral centrifugation provoked an increase of DD symptoms in both healthy volunteers and the entire group of patients (repeated measures ANOVA, p

Amblyopia is a relatively common (incidence 3%) developmental disorder in which there is loss of vision as a consequence of a disruption to normal visual development. Although the deficit is monocular and known to be of cortical origin, the nature of the processing deficit is controversial. Human behavioral studies have identified two main deficits - a loss of contrast sensitivity and perceived spatial distortions. Here we use a multifocal fMRI approach to ascertain, in a group of anisometropic amblyopes, whether these two deficits have a single common cause or whether they are the result of two underlying independent cortical disorders. We found that fMRI magnitudes were attenuated in amblyopic eye stimulation, and that there was poor fidelity for co-localization of the activity clusters between the amblyopic and fellow-fixing eye stimulation. These effects varied across eccentricities and correlate with the degree of amblyopia but not with one another, suggesting two independent cortical deficits: a reduced responsiveness as well as reduced fidelity of spatial representation. These deficits are independent of eccentricity within the central field and consistent across early cortical visual areas.

Objectives To assess bone conduction (BC) thresholds following radical mastoidectomy and subtotal petrosectomy, in which the tympanic membrane and the ossicular chain, responsible for osseous BC mechanisms, are surgically removed. The removal of the tympanic membrane and the ossicular chain would reduce the contributions to BC threshold of the following four osseous BC mechanisms: the occlusion effect of the external ear, middle ear ossicular chain inertia, inner ear fluid inertia, and distortion (compression-expansion) of the walls of the inner ear. Materials and methods BC thresholds were determined in 64 patients who underwent radical mastoidectomy and in 248 patients who underwent subtotal petrosectomy. Results BC thresholds were normal (≤15 dB HL, i.e., better) in 19 (30%) radical mastoidectomy patients and in 19 (8%) subtotal petrosectomy patients at each of the frequencies assessed (0.5, 1.0, 2.0, and 4.0 kHz). Conclusion Normal BC thresholds seen in many patients following mastoidectomy and petrosectomy may be induced by a non-osseous mechanism, and the onset ("threshold") of the classical osseous BC mechanisms may be somewhat higher.

The digital medical workflow faces many circumstances in which the images can be manipulated during viewing, extracting and exchanging. Reversible and imperceptible watermarking approaches have the potential to enhance trust within the medical imaging pipeline through ensuring the authenticity and integrity of the images to confirm that the changes can be detected and tracked. This study concentrates on the imperceptibility issue. Unlike reversibility, for which an objective assessment can be easily made, imperceptibility is a factor of human cognition that needs to be evaluated within the human context. By defining a perceptual boundary of detecting the modification, this study enables the formation of objective guidelines for the method of data encoding and level of image/pixel modification that translates to a specific watermark magnitude. \ud This study implements a relative Visual Grading Analysis (VGA) evaluation of 117 brain MR images (8 original and 109 watermarked), modified by varying techniques and magnitude of image/pixel modification to determine where this perceptual boundary exists and relate the point at which change becomes noticeable to the objective measures of the image fidelity evaluation. \ud The outcomes of the visual assessment were linked to the images Peak Signal to Noise Ratio (PSNR) values, thereby identifying the visual degradation threshold. The results suggest that, for watermarking applications, if a watermark is applied to the 512x512 pixel (16 bpp grayscale) images used in the study, a subsequent assessment of PSNR=82dB or greater would mean that there would be no reason to suspect that the watermark would be visually detectable. \ud Keywords: Medical imaging; DICOM; Reversible Watermarking; Imperceptibility; Image Quality; Visual Grading Analysis.

Multi-view video coding (MVC) utilizes hierarchical B picture prediction structure and adopts many coding techniques to remove spatiotemporal and inter-view redundancies at the cost of high computational complexity. In this paper, a novel perceptual distortion threshold model (PDTM) is proposed to reveal the relationship between the mode selection of inter-frame prediction and coding distortion threshold. Based on the proposed PDTM, a new fast inter-frame prediction algorithm in MVC is developed aimed at minimizing computational complexity for dependent view coding. Then the fast MVC algorithm is incorporated into the multi-view High Efficiency Video Coding (MV-HEVC) software to improve MVC coding efficiency. In practical coding, the mode selection for inter-frame prediction of dependent views may be early terminated based on the thresholds derived from the PDTM, thereby reducing the coding time complexity. Experimental results demonstrate that the proposed algorithm can reduce the computational complexity of the dependent views by 52.9% compared with the HTM14.1 algorithm under the coding structure of hierarchical B pictures. Moreover, the bitrate is increased by 0.9% under the same subjective quality and only increased by 1.0% under the same objective quality peak signal-to-noise ratio (PSNR). Compared with the state-of-the-art fast algorithm, the proposed algorithm can save more coding time, while the bitrate under the same PSNR increases slightly.

The conventional rate control algorithm does not fully consider the characteristics of the Human Visual System (HVS). To address this problem, in this paper, a perception based Coding Tree Unit (CTU) level bit allocation algorithm for intra High Efficiency Video Coding (HEVC) is proposed, which aims to minimize the perceptual distortion of each CTU under a given bit rate constraint. Firstly, to better represent perceptual distortion, Perceptually Weighted Mean Squared Error (PWMSE) is adopted instead of Mean Squared Error (MSE). Then, the relationship between Rate (R) and Perceptually Weighted Distortion (Dr) is formulated by the proposed R-Dr model. Finally, the perceptual weighting factor derived from the R-Dr model is used to guide CTU level bit allocation. Experimental results show that the proposed algorithm achieves 6.27% bit rate reduction and 0.38 dB Bjøntegaard Delta Perceptually Weighted Peak Signal to Noise Ratio (BD-PWPSNR) gain on average. Under other seven quality evaluation metrics, the proposed algorithm achieves from 1.57% to 8.95% average bit rate reduction while maintaining the perceptual quality, which significantly outperforms the benchmark schemes. Moreover, the proposed perception-based CTU level bit allocation algorithm also maintains a high rate control accuracy, which reaches 99.997%.

High efficiency video coding (HEVC) is standard in the video compression field and performs well not only in video compression coding, but also in image compression. Regions of interest (ROIs) and just noticeable difference (JND), two human visual models, can accurately quantify human visual system (HVS) characteristics as pixel values. Using ROIs and JND to assist in evaluating image distortion can effectively reduce human visual redundancy and reflect authentic perceptual distortions. However, they are not readily applicable to the HEVC test model (HM) in the pixel domain. It is difficult to secure a suitable Lagrange multiplier $\lambda $ and quantization parameter (QP) for the JND model in particular. This paper proposes different solutions for the use of rate control (RC) or not where an appropriate $\lambda $ value is available for perceptual models. In RC, the proposed approach centers on a robust relationship between QP and achieved $\lambda $ . And we also established a bit allocation technique using the related $\lambda $ and expression for the RC model. Experimental results validate the rationality and effectiveness of the proposed method.

Reversible and imperceptible watermarking is recognized as a robust approach to confirm the integrity and authenticity of medical images and to verify that alterations can be detected and tracked back. In this paper, a novel blind reversible watermarking approach is presented to detect intentional and unintentional changes within brain Magnetic Resonance (MR) images. The scheme segments images into two parts; the Region of Interest (ROI) and the Region of Non Interest (RONI). Watermark data is encoded into the ROI using reversible watermarking based on the Difference Expansion (DE) technique. Experimental results show that the proposed method, whilst fully reversible, can also realize a watermarked image with low degradation for reasonable and controllable embedding capacity. This is fulfilled by concealing the data into ‘smooth’ regions inside the ROI and through the elimination of the large location map required for extracting the watermark and retrieving the original image. Our scheme delivers highly imperceptible watermarked images, at 92.18–99.94 dB Peak Signal to Noise Ratio (PSNR) evaluated through implementing a clinical trial based on relative Visual Grading Analysis (relative VGA). This trial defines the level of modification that can be applied to medical images without perceptual distortion. This compares favorably to outcomes reported under current state-of-art techniques. Integrity and authenticity of medical images are also ensured through detecting subsequent changes enacted on the watermarked images. This enhanced security measure, therefore, enables the detection of image manipulations, by an imperceptible approach, that may establish increased trust in the digital medical workflow.

The susceptibility of distortions introduced by compression from the point of view of human perception is an important area of research. The ultimate purpose of video quality assessment is to emulate the performance of the biological visual system. Perceptual distortion models have proven successful in describing spatial coding in all human visual systems. However, the question of how the visual regions of the human brain process temporal information have received significantly less attention. Based on the researches of limit to human vision, here we offer a method, software, and test equipment for research and measure the characteristics of human visual systems. This set forms and evaluates stimuli with a specified combination of spatial, temporal, and color characteristics, which differ in a narrowband enough spectrum for measurements.

In this paper, we concentrate on the super-resolution (SR) of compressed screen content video, in an effort to address the real-world challenges by considering the underlying characteristics of screen content. Firstly, we propose a new dataset for the SR of screen content video with different distortion levels. Meanwhile, we design an efficient SR structure that could capture the characteristics of compressed screen content video and manipulate the inner-connections in consecutive compressed low-resolution frames, facilitating the high-quality recovery of the high-resolution counter-part. Moreover, we design a new loss function for network training to better remedy the compression distortion and perceptual distortion. Experimental results demonstrate the effectiveness and superiority of the proposed method.

For omnidirectional videos (ODVs), the existing off-line coding approaches are designed based on the spatial or perceptual distortion in a whole ODV frame, ignoring the fact that subjects can only access viewports. To improve the subjective quality inside the viewports, this paper proposes an off-line viewport-adaptive rate control (RC) approach for ODVs in high efficiency video coding (HEVC) framework. Specifically, we predict the viewport candidates with importance weights and develop a viewport saliency detection model. Then, the predicted candidates and detected saliency are taken into account in our viewport-adaptive CTU traversal and bit allocation scheme. Finally, the experimental results validate that our approach is effective in saving bit-rates and improving subjective quality for encoding ODVs; meanwhile, our approach is also effective in the auxiliary task of saliency detection in viewports.

BackgroundIn individuals with body dysmorphic disorder (BDD), selective attention biases and aberrant visual scanning patterns may cause imbalances in global vs. detailed visual processing, contributing to perceptual distortions for appearance. The mechanistic effects of modifying visual attention on brain function in BDD, which may be critical to developing perceptual-based treatments, have not been explored. This study tested the effects of visual-attention modulation on dorsal and ventral visual stream activation and connectivity, and eye behaviors.MethodsWe acquired functional magnetic resonance imaging data in 37 unmedicated adults with BDD and 30 controls. Participants viewed their faces under two conditions: a) unconstrained (naturalistically), and b) holding their gaze on the center of the image (visual-attention modulation), monitored with an eye-tracking camera. We analyzed activation and dynamic effective connectivity in dorsal and ventral visual streams and visual fixation duration.ResultsVisual-attention modulation resulted in longer fixation duration and reduced activation in dorsal and ventral visual streams in both groups compared with naturalistic viewing. Longer fixation duration was associated with greater effective connectivity from V1 to early dorsal visual stream during the second naturalistic viewing, across groups. During naturalistic viewing, there was greater V1 to early dorsal visual stream connectivity after, compared with before, visual-attention modulation.ConclusionsWhen viewing one’s face, longer visual fixation may confer greater communication in dorsal visual system, facilitating global/holistic visual processing. The finding that reduction in visual scanning while viewing one’s face results in persistent effects during unconstrained viewing has implications for perceptual retraining treatment design for BDD.

Concurrent body movements have been shown to enhance the accuracy of spatial judgment, but it remains unclear whether they also contribute to perceptual estimates of gravitational space not involving body movements. To address this, we evaluated the effects of static or dynamic arm movements during prolonged whole-body tilt on the subsequent perceptual estimates of visual or postural vertical. In Experiment 1, participants were asked to continuously perform static or dynamic arm movements during prolonged tilt, and we assessed their effects on the prolonged tilt-induced shifts of subjective visual vertical (SVV) at a tilted position (during-tiltsession) or near upright (post-tiltsession). In Experiment 2, we evaluated how static or dynamic arm movements during prolonged tilt subsequently affected the subjective postural vertical (SPV). In Experiment 1, we observed that the SVV was significantly shifted toward the direction of prolonged tilt in both sessions. The SVV shifts decreased when performing dynamic arm movements in theduring-tiltsession, but not in thepost-tiltsession. In Experiment 2, as well as SVV, the SPV was shifted toward the direction of prolonged tilt, but it was not significantly attenuated by the performance of static or dynamic arm movements. The results of theduring-tiltsession suggest that the central nervous system utilizes additional information generated by dynamic body movements for perceptual estimates of visual vertical.

The sources and consequences of a sensorineural hearing loss are diverse. While several approaches have aimed at disentangling the physiological and perceptual consequences of different etiologies, hearing deficit characterization and rehabilitation have been dominated by the results from pure-tone audiometry. Here, we present a novel approach based on data-driven profiling of perceptual auditory deficits that attempts to represent auditory phenomena that are usually hidden by, or entangled with, audibility loss. We hypothesize that the hearing deficits of a given listener, both at hearing threshold and at supra-threshold sound levels, result from two independent types of “auditory distortions”. In this two-dimensional space, four distinct “auditory profiles” can be identified. To test this hypothesis we gathered a dataset consisting of a heterogeneous group of listeners that were evaluated using measures of speech intelligibility, loudness perception, binaural processing abilities and spectro-temporal resolution. The subsequent analysis revealed that distortion type-I was associated with elevated hearing thresholds at high frequencies and reduced temporal masking release and was significantly correlated with elevated speech reception thresholds in noise. Distortion type-II was associated with low-frequency hearing loss and abnormally steep loudness functions. The auditory profiles represent four robust subpopulations of hearing-impaired listeners that exhibit different degrees of perceptual distortions. The four auditory profiles may provide a valuable basis for improved hearing rehabilitation, e.g. through profile-based hearing-aid fitting

Continuous human annotations of complex human experiences are essential for enabling psychological and machine-learned inquiry into the human mind, but establishing a reliable set of annotations for analysis and ground truth generation is difficult. Measures of consensus or agreement are often used to establish the reliability of a collection of annotations and thereby purport their suitability for further research and analysis. This work examines many of the commonly used agreement metrics for continuous-scale and continuous-time human annotations and demonstrates their shortcomings, especially in measuring agreement in general annotation shape and structure. Annotation quality is carefully examined in a controlled study where the true target signal is known and evidence is presented suggesting that annotators' perceptual distortions can be modeled using monotonic functions. A novel measure of agreement is proposed which is agnostic to these perceptual differences between annotators and provides unique information when assessing agreement. We illustrate how this measure complements existing agreement metrics and can serve as a tool for curating a reliable collection of human annotations based on differential consensus.

A longstanding debate in the face recognition field concerns the format of face representations in the brain. New face research clarifies some of this mystery by revealing a face-centered format in a patient with a left splenium lesion of the corpus callosum who perceives the right side of faces as ‘melted’.

Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted perception of appearance, yet no studies have directly compared the neurobiology associated with body perception. We compared AN and BDD in brain activation and connectivity in relevant networks when viewing images of others' bodies and tested their relationships with clinical symptoms and subjective appearance evaluations. We acquired fMRI data from 64 unmedicated females (20 weight-restored AN, 23 BDD, 21 controls) during a matching task using unaltered or spatial-frequency filtered photos of others' bodies. Using general linear model and independent components analyses we compared brain activation and connectivity in visual, striatal, and parietal networks and performed univariate and partial least squares multivariate analyses to investigate relationships with clinical symptoms and appearance evaluations. AN and BDD showed partially overlapping patterns of hyperconnectivity in the dorsal visual network and hypoconnectivity in parietal network compared with controls. BDD, but not AN, demonstrated hypoactivity in dorsal visual and parietal networks compared to controls. Further, there were significant activity and connectivity differences between AN and BDD in both networks. In both groups, activity and/or connectivity were associated with symptom severity and appearance ratings of others' bodies. Thus, AN and BDD demonstrate both distinct and partially-overlapping aberrant neural phenotypes involved in body processing and visually encoding global features. Nevertheless, in each disorder, aberrant activity and connectivity show relationships to clinically relevant symptoms and subjective perception. These results have implications for understanding distinct and shared pathophysiology underlying perceptual distortions of appearance and may inform future novel treatment strategies.

Staranje je naravni proces, ki mu ni moč uiti. Četudi je proces naraven, smo kot družba nenaklonjeni starejšim osebam. Ta nenaklonjenost se odraža tudi na trgu delovne sile. Starejše osebe so pogosteje brezposelne in so manjkrat povabljene na razgovor za zaposlitev. Starejši kandidati in zaposleni so po zakonu varovana kategorija in starost je ena od lastnosti, glede na katero je prepovedano diskriminirati. A kljub temu prihaja do različne obravnave. Za starejše kandidate in zaposlene veljajo stereotipi, da si ne želijo sprememb in novega znanja ter se s težavo učijo uporabe nove tehnologije. Stereotip je le ena od napak zaznavanja kadrovikov, ki prihajajo na površje v procesu zaposlovanja. Ta negativna zaznava starejših oseb najbolje osvetljuje raziskovalni problem – obravnavo starejših oseb pri zaposlovanju. Zaradi človeškega faktorja pri selekcijskem intervjuju je v procesu zaposlovanja veliko možnosti za pojavljanje napak zaznavanja in posledično subjektivnih odločitev kadrovikov. Najpogostejše napake zaznavanja starejših so stereotipi, halo efekt, selektivno zaznavanje in samoizpolnjujoča se napoved. Tako iz teoretične kot empirične raziskave je razvidno, da so starejši kandidati in kandidatke v procesu selekcije in zaposlovanja diskriminirani. Ageing is a natural process no one can escape. Natural as it is, our society is mistreating older people nonetheless. This mistreatment can also be seen in the labor market. Older people are more likely to be unemployed and receive fewer calls for a job interview. Older people are protected by law, stating it is illegal to discriminate on the grounds of age. Even with it being illegal, discrimination based on age still exists. There are three main sterotypes regarding older people. They are not prone to change, they do not want to learn new skills and they struggle with new technology. A stereotype is only one of HR manager's perceptual distortions that happen during the employment process. This negative perception of older people is the foundation and reason for my research. The human factor in conducting a job interview allows the perceptual distortions to appear, consequently making HR manager's decisions biased. The most common perceptual distortions regarding age are stereotypes, halo effects, selective perception and self-fulfilling prophecies. The theoretical and empirical research in this thesis made apparent that older job candidates are discriminated against in the process of candidate selection and employment.

Visual awareness is thought to result from integration of low- and high-level processing; instances of integration failure provide a crucial window into the cognitive and neural bases of awareness. We present neurophysiological evidence of complex cognitive processing in the absence of awareness, raising questions about the conditions necessary for visual awareness. We describe an individual with a neurodegenerative disease who exhibits impaired visual awareness for the digits 2 to 9, and stimuli presented in close proximity to these digits, due to perceptual distortion. We identified robust event-related potential responses indicating 1) face detection with the N170 component and 2) task-dependent target-word detection with the P3b component, despite no awareness of the presence of faces or target words. These data force us to reconsider the relationship between neural processing and visual awareness; even stimuli processed by a workspace-like cognitive system can remain inaccessible to awareness. We discuss how this finding challenges and constrains theories of visual awareness.

Steganography is a technique of concealing the message in multimedia data. Multimedia data, such as videos are often compressed to reduce the storage for limited bandwidth. The video provides additional hidden-space in the object motion of image sequences. This research proposes a video steganography scheme based on object motion and DCT-psychovisual for concealing the message. The proposed hiding technique embeds a secret message along the object motion of the video frames. Motion analysis is used to determine the embedding regions. The proposed scheme selects six DCT coefficients in the middle frequency using DCT-psychovisual effects of hiding messages. A message is embedded by modifying middle DCT coefficients using the proposed algorithm. The middle frequencies have a large hiding capacity and it relatively does not give significant effect to the video reconstruction. The performance of the proposed video steganography is evaluated in terms of video quality and robustness against MPEG compression. The experimental results produce minimum distortion of the video quality. Our scheme produces a robust of hiding messages against MPEG-4 compression with average NC value of 0.94. The proposed video steganography achieves less perceptual distortion to human eyes and it's resistant against reducing video storage.

BACKGROUND: Chronic orofacial pain (COP) patients often perceive the painful face area as "swollen" without clinical signs; such self-reported illusions of the face are termed perceptual distortion (PD). The pathophysiological mechanisms underlying PD remain elusive. OBJECTIVE: To test the neuromodulatory effect of repetitive transcranial magnetic stimulation (rTMS) on PD in healthy individuals, to gain insight into the cortical mechanisms underlying PD. METHODS: PD was induced experimentally by injections of local anesthetic (LA) around the infraorbital nerve and measured as perceived size changes of the affected area. Participants were randomly allocated to inhibitory rTMS (n = 26) or sham rTMS (n = 26) group. The participants rated PD at baseline, 6 min after LA, immediately, 20 and 40 min after rTMS. The rTMS (inhibitory and sham) was applied to face (lip) representation area of primary somatosensory cortex (SI) as an intervention at 10 min after the LA, when the magnitude of PD is large. As inhibitory rTMS, continuous theta-burst stimulation paradigm (50 Hz) for 40s was employed to inhibit cortical activity. RESULTS: We demonstrated a significant decrease in the magnitude of PD immediately and 20 min after the application of inhibitory rTMS compared with sham rTMS (P

Tactile perception is referenced to, and modulated by, body parts and their boundaries. For example, tactile distances presented over the wrist are perceptually elongated relative to those presented within the hand or arm. This phenomenon is argued to result from a segmentation of tactile space according to body parts and their boundaries, i.e., touches presented within a body part are perceived as being more similar, and therefore closer together, whereas those that straddle a body part boundary (e.g. presented across two body parts) are perceived as more distinct and thus further apart. We tested the hypothesis that language shapes this effect by providing consolidatory labels for categories and boundaries, as it does in other perceptual domains. We examined the perceptual elongation of distance over the wrist in a group of Croatian adults (n = 37) whose first language does not differentiate between hand and arm at the wrist in common noun terms (instead, the Croatian word “ruka” encompasses the entire limb). Croatian adults, like UK adults reported in a previous study (Le Cornu Knight, Longo, & Bremner, 2014), perceived distances presented proximodistally over the wrist boundary as longer than those presented mediolaterally, whereas the reverse was found for both the hand and the arm. This pattern of results was remained when Croatian participants were split into two groups of inexperienced or proficient English-language speakers. This is striking evidence that body part boundaries consistently modulate tactile perception, despite differences in the linguistic distinctions of such body parts made by one's first language.

Additional gravitational cues generated by active body movements may play a role in the perception of gravitational space, but no experimental evidence has been shown on this. To investigate this possibility, we evaluated how arm movements made against gravity influenced the perceptual distortion of visual and postural vertical induced by prolonged whole-body tilt. In Experiment 1, participants were asked to perform static or dynamic arm movements during prolonged whole-body tilt and we assessed their effects on subjective visual vertical (SVV) at the tilt position (during-tiltsession) and after tilting back to the upright position (post-tiltsession). In Experiment 2, we evaluated how static or dynamic arm movements during prolonged tilt subsequently affected the subjective postural vertical (SPV). In Experiment 1, we observed that prolonged tilt induced the SVV shifts toward the side of body tilts in both sessions. The prolonged tilt-induced SVV shifts effectively decreased when performing dynamic arm movements in theduring-tiltsession, but not in thepost-tiltsession. In Experiment 2, the SPV shifted toward the side of prolonged body tilt, which was not significantly influenced by the performance of static or dynamic arm movements. Results of theduring-tiltsession suggest that the central nervous system utilizes additional cues generated by dynamic body movements for the perception of the visual vertical.