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PURPOSE: We aimed the develop and validate a computerized version of the MNREAD for the assessment of reading speed for children. METHODS: A computerized version of the MNREAD was built in Psykinematix software using the same parameters as the physical chart. We measured the reading velocity of 104 children (n = 44 of the 3rd grade; n = 60 of the 5th grade). Bland-Altaman analysis was used to quantify agreement between two chart measurements. RESULTS: Comparison between the 3rd and 5th-grade children for physical and computerized MNREAD versions showed statistical differences in Maximum Reading Speed (F = 2669.6; p < 0.001), Critical Print Size (F = 17.49; p < 0.001), and Reading Acuity (F = 14.19; p = 0.002) with huge effect size (η2 = 0.930). No differences were found between the versions within grades. Bland-Altman analysis showed 95% of the data points within ± 2 s of the mean difference, suggesting a similarity between versions of the MNREAD parameters. CONCLUSION: Our reading speed values for children in the 5th grade were higher than previous studies, suggesting a better quality of the assessment in the computerized version. Tolerance Limits were calculated as normality references for clinical purposes.

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BACKGROUND: Since color measurements are relative, the discrepancy among different instruments is alarmingly high. This multicenter study evaluated the effectiveness of instrument calibration and inter-instrument harmonization of different spectrophotometers with the same optical geometry using tooth-colored, translucent dental materials. METHODS: The coordinating center (CC) spectrophotometer was calibrated using the NPL Ceram Series II set. Two sets of 10 specimens, labeled 1 to 10 and I to X (10 mm in diameter and 1 mm thick), were tested at CC and three research sites (RS1, RS2, and RS3) using the same d/8° optical geometry spectrophotometers. Calibration factors were calculated for each material and site to obtain the average calibration factors for sets 1-10, set I-X, and the combination of both. The differences among the non-corrected and corrected reflection values were calculated using CIEDE2000 (DeltaE00) and CIELAB (DeltaEab) color difference formulas and were submitted to ANOVA and Tukey test (α = 0.05). RESULTS: A significant decrease of color differences between non-corrected as compared to corrected measurements was recorded for all CC-RS and RS-RS comparisons. The reduction of DeltaE00 values between non-corrected and corrected for CC-RS1, CC-RS2, and CC-RS3 were 83.1%, 77.2%, and 73.6%, respectively. The corresponding DeltaE00 values for RS1-RS2, RS1-RS3, and RS2-RS3 comparisons, indirectly compared in the experiment, were 84.2%, 82.8%, and 68.5%, respectively. There was a significant reduction of DeltaE00 and DeltaEab color difference for all combined RS pairs and each of three RS pairs, corrected with one of two specimen sets calibration factors separately. CONCLUSIONS: Calibration and harmonization of color measurements in dentistry using tooth-colored, translucent restorative materials significantly decreased measurement discrepancies between the coordinating center and research sites and among pairs of research sites.

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RESUMEN No todos sentimos lo mismo ante un estímulo físico, cada uno expresa una sensación con diferentes palabras, no todos describimos de igual forma las sensaciones respi ratorias y, por qué no decirlo, no todos los profesionales entienden lo que el paciente les relata. La psicofísica de la disnea (las relaciones cuantitativas entre un estímulo respiratorio y una sensación), los descriptores para referirse a la falta de aire (el lenguaje de la disnea) pueden ayudar a romper las barreras comunicacionales entre pacientes, familia y personal de salud. Los datos generales apoyan una red cortical-límbica para la percepción de la disnea. Hay acuerdo en que la corteza insular es un elemento central esencial para el circuito neuronal, mientras que la corteza cingulada anterior y la corteza prefrontal dorsolateral se cree que modulan la magnitud de la percepción de disnea y su alivio. La disnea como un fenómeno del sistema nervioso central y con dimensiones tanto sensoriales como afectivas, esto ha sido confirmado en estudios de neuroimágenes. Se ha establecido firmemente que la disnea es una experiencia com pleja de la mente y el cuerpo, que comprende diferentes sensaciones que solo pueden ser percibidas por el individuo. Los componentes afectivos impulsan los sentimientos acompañantes de angustia, miedo y ansiedad, y es el cerebro, no los pulmones, el que genera estos fenómenos.

ABSTRACT When confronted with a physical stimulus, not everyone feels the same way; each one expresses a sensation with different words; not all of us describe respiratory sensations in the same way; and, why not say it, not all professionals understand what the patient tells them. The psychophysics of dyspnea (the quantitative relationships between a re spiratory stimulus and a sensation) and descriptors for shortness of breath (the dyspnea language) can aid in breaking down communication barriers between patients, families, and health care personnel. The insular cortex is widely agreed to be an important cen tral component of neural circuitry, while the anterior cingulate cortex and dorsolateral prefrontal cortex are thought to modulate the magnitude of dyspnea perception and its relief. Dyspnea is a central nervous system phenomenon, and neuroimaging studies have confirmed this with both sensory and affective dimensions. Dyspnea is a complex mind-body experience that consists of different sensations that can only be perceived by the individual. The accompanying feelings of distress, fear, and anxiety are driven by affective components, which are generated by the brain rather than the lungs.

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ABSTRACT Objective: To validate visual acuity measurements using a cross-platform system in an ophthalmological setting. Methods: Visual acuity was assessed at a distance of 5m using two different modalities: printed and digital optotypes. The devices included Android, LG WebOS and Samsung Tizen smart TVs. Optotypes were presented in the logMAR scale. Two modalities, a single row and a block of symbols, presented Sloan letters and Tumbling E symbols. Results: Visual acuity measurements of 190 participants aged 12 to 60 years demonstrated good-to-strong test-retest correlation (Intraclass Correlation Coefficient >0.75) and minimal bias (-0.03 to 0.02 logMAR). Limits of agreement were comparable to other studies (0.13 to 0.26 logMAR), with the smallest values for Tumbling E row presentation in all devices and the highest value for Sloan chart in LG device. Analysis of variance revealed no statistical differences in visual acuity across devices. Sloan letters showed superior visual acuity compared to Tumbling E (p<0.001); however, this difference corresponded to only 2 letters of visual acuity. Conclusion: The digital cross-platform evaluated serves as a versatile substitute for traditional visual acuity assessments in individuals aged 12 years and older. Further research is necessary for patients with visual acuity worse than 0.5 logMAR and to conduct vision screenings in young children.

RESUMO Objetivo: Validar as medições de acuidade visual utilizando um sistema multiplataforma em um contexto clínico oftalmológico. Métodos: A acuidade visual foi avaliada a uma distância de 5m usando duas modalidades diferentes: optotipos impressos e digitais. Os dispositivos incluíram smart TVs Android, LG WebOS e Samsung Tizen. Os optotipos foram apresentados na escala logMAR. Duas modalidades, sendo uma fila única e um bloco de símbolos, apresentaram letras Sloan e os símbolos Tumbling E. Resultados: Medidas de acuidade visual de 190 participantes de 12 a 60 anos demonstraram boa a forte correlação teste-reteste (Coeficiente de Correlação Intraclasse >0,75) e viés mínimo (-0,03 a 0,02 logMAR). Os limites de concordância foram comparáveis aos de outros estudos (0,13 a 0,26 logMAR), com os menores valores para a apresentação em linha única do Tumbling E em todos os dispositivos e o maior valor para o gráfico Sloan no dispositivo LG. A análise de variância revelou não haver diferenças estatísticas na acuidade visual entre os dispositivos. As letras Sloan mostraram acuidade visual superior em comparação com Tumbling E (p<0,001), no entanto, essa diferença correspondeu a apenas duas letras de acuidade visual. Conclusão: O teste digital multiplataforma serve como um substituto versátil para avaliações tradicionais de acuidade visual em indivíduos a partir de 12 anos de idade. Pesquisas adicionais são necessárias para pacientes com acuidade visual inferior a 0,5 logMAR e a realização de triagens visuais em crianças pequenas.

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While eye tracking is a technique commonly used in the experimental study of higher-level perceptual processes such as visual search, working memory, reading, and scene exploration, its use for the quantification of basic visual functions (visual acuity, contrast sensitivity, color vision, motion detection) is less explored. The use of eye movement features as dependent variables in a psychophysical investigation can serve multiple roles. They can be central in studies with neurological patients or infants that cannot comply with verbal instructions, understand task demands, and/or emit manual responses. The technique may also serve a complementary role, determining the conditions under which a manual or verbal response is given, such as stimulus position in the visual field, or it can afford the analysis of new dependent variables, such as the time interval between oculomotor and manual responses. Our objective is to review the literature that applied the eye tracking technique to psychophysical problems. The two questions our review raises are: can eye movements (reflex or voluntary) be an objective index of stimulus detection in psychophysical tasks? If so, under what conditions, and how does it compare with traditional paradigms requiring manual responses? Our (non-systematic) methodological review selected studies that used video-oculography as the technique of choice and had a basic visual function as their primary object of investigation. Studies satisfying those criteria were then categorized into four broad classes reflecting their main research interest: (1) stimulus detection and threshold estimation, (2) the effects of stimulus properties on fixational eye movements, (3) the effects of eye movements on perception, and (4) visual field assessment. The reviewed studies support the idea that eye tracking is a valuable technique for the study of basic perceptual processes. We discuss methodological characteristics within each of the proposed classification area, with the objective of informing future task design.

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The belief that learning can be modulated by social context is mainly supported by high-level value-based learning studies. However, whether social context can even modulate low-level learning such as visual perceptual learning (VPL) is still unknown. Unlike traditional VPL studies in which participants were trained singly, here, we developed a novel dyadic VPL paradigm in which paired participants were trained with the same orientation discrimination task and could monitor each other's performance. We found that the social context (i.e., dyadic training) led to a greater behavioral performance improvement and a faster learning rate compared with the single training. Interestingly, the facilitating effects could be modulated by the performance difference between paired participants. Functional magnetic resonance imaging (fMRI) results showed that, compared with the single training, social cognition areas including bilateral parietal cortex and dorsolateral prefrontal cortex displayed a different activity pattern and enhanced functional connectivities to early visual cortex (EVC) during the dyadic training. Furthermore, the dyadic training resulted in more refined orientation representation in primary visual cortex (V1), which was closely associated with the greater behavioral performance improvement. Taken together, we demonstrate that the social context, learning with a partner, can remarkably augment the plasticity of low-level visual information process by means of reshaping the neural activities in EVC and social cognition areas, as well as their functional interplays.

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Background: Resting-state functional connectivity (rs-FC) may aid in understanding the link between pain-modulating brain regions and the descending pain modulatory system (DPMS) in fibromyalgia (FM). This study investigated whether the differences in rs-FC of the primary somatosensory cortex in responders and non-responders to the conditioned pain modulation test (CPM-test) are related to pain, sleep quality, central sensitization, and the impact of FM on quality of life. Methods: This cross-sectional study included 33 females with FM. rs-FC was assessed by functional magnetic resonance imaging. Change in the numerical pain scale during the CPM-test assessed the DPMS function. Subjects were classified either as non-responders (i.e., DPMS dysfunction, n = 13) or responders (n = 20) to CPM-test. A generalized linear model (GLM) and a receiver operating characteristic (ROC) curve analysis were performed to check the accuracy of the rs-FC to differentiate each group. Results: Non-responders showed a decreased rs-FC between the left somatosensory cortex (S1) and the periaqueductal gray (PAG) (P < 0.001). The GLM analysis revealed that the S1-PAG rs-FC in the left-brain hemisphere was positively correlated with a central sensitization symptom and negatively correlated with sleep quality and pain scores. ROC curve analysis showed that left S1-PAG rs-FC offers a sensitivity and specificity of 85% or higher (area under the curve, 0.78, 95% confidence interval, 0.63-0.94) to discriminate who does/does not respond to the CPM-test. Conclusions: These results support using the rs-FC patterns in the left S1-PAG as a marker for predicting CPM-test response, which may aid in treatment individualization in FM patients.

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Different studies on temporal control of behavior have focused on making modifications to experimental tasks by introducing disruptors to know how these manipulations modify temporal control. The aim of this study was to produce changes in temporal discrimination in a temporal bisection task by using a disruptor associated with motivation, which consisted in delivering reinforcement during the intertrial interval (RITI). Four Wistar rats and a pair of duration 2s-8s were used. There were two types of sessions: baseline generalization, where the disruptor was not applied, and RITI generalization, where the disruptive manipulation was applied. The analysis of results consisted of comparing psychophysical parameters, Signal Detection Theory indices, and latencies to start trials of baseline sessions and disruption sessions. The results showed a change in the point of subjective equality, a change in the psychophysical function, an increasing trend in the latencies to start trials on RITI disruption, and no change in the Signal Detection Theory indices. The results highlight the importance of incorporating motivational explanations to theories of temporal control in non-human organisms.

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A comparative single-evaluation cross-sectional study was performed to evaluate cognitive damage in post-COVID-19 patients. The psychophysics tests of Two-Alternative Forced Choice (2AFC) and Simple Reaction Time (SRT), under a designed virtual environment, were used to evaluate the cognitive processes of decision-making, visual attention, and information processing speed. The population under study consisted of 147 individuals, 38 controls, and 109 post-COVID patients. During the 2AFC test, an Emotiv EPOC+® headset was used to obtain EEG signals to evaluate their Focus, Interest, and Engagement metrics. Results indicate that compared to healthy patients or recovered patients from mild-moderate COVID-19 infection, patients who recovered from a severe-critical COVID infection showed a poor performance in different cognitive tests: decision-making tasks required higher visual sensitivity (p = 0.002), Focus (p = 0.01) and information processing speed (p < 0.001). These results signal that the damage caused by the coronavirus on the central nervous and visual systems significantly reduces the cognitive processes capabilities, resulting in a prevalent deficit of 42.42% in information processing speed for mild-moderate cases, 46.15% for decision-making based on visual sensitivity, and 62.16% in information processing speed for severe-critical cases. A psychological follow-up for patients recovering from COVID-19 is recommended based on our findings.

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PURPOSE: We developed a contrast sensitivity test that considers an integrative approach of spatial and temporal frequencies to evaluate the psychophysical channels in processing two-dimensional stimulus for clinical use. Our new procedure provides a more efficient isolation of the magnocellular and parvocellular visual pathways supporting spatiotemporal contrast sensitivity processing. METHODS: We evaluated 36 participants of both sexes aged 18-30 years with 20/20 or better best-corrected visual acuity. Two spatial frequencies (0.5 cycles per degree [cpd] and 10 cpd), being in one of the three temporal frequencies (0.5 cycle per second [cps], 7.5 cps, and 15 cps), were presented in a high-resolution gamma corrected monitor. A two-alternative forced-choice procedure was conducted, and the staircase method was used to calculate the contrast sensitivity. Reliability was assessed using a retest procedure within a month ( ± 5 days) under the same conditions. RESULTS: Results showed statistical significance in 0.5 cpd and 10 cpd spatial frequencies for 0.5 cps (F = 77.36; p < 0.001), 7.5 cps (F = 778.37; p < 0.001), and 15 cps (F = 827.23; p < 0.001) with a very high (η ² = 0.89) effect size. No statistical differences were found between the first and second sessions for all spatial frequencies. For reliability, a significantly high correlation and high internal consistency were found in all spatiotemporal conditions. The limits were calculated for normality. CONCLUSION: We developed an approach to investigate the spatiotemporal integration of contrast sensitivity designed for clinical purposes. The relative contribution of the low spatial frequencies/high temporal frequencies and the high spatial frequencies/low temporal frequencies of the psychophysical channels can also be evaluated separately.

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In social animals, identifying sounds is critical for communication. In humans, the acoustic parameters involved in speech recognition, such as the formant frequencies derived from the resonance of the supralaryngeal vocal tract, have been well documented. However, how formants contribute to recognizing learned sounds in non-human primates remains unclear. To determine this, we trained two rhesus monkeys to discriminate target and non-target sounds presented in sequences of 1-3 sounds. After training, we performed three experiments: (1) We tested the monkeys' accuracy and reaction times during the discrimination of various acoustic categories; (2) their ability to discriminate morphing sounds; and (3) their ability to identify sounds consisting of formant 1 (F1), formant 2 (F2), or F1 and F2 (F1F2) pass filters. Our results indicate that macaques can learn diverse sounds and discriminate from morphs and formants F1 and F2, suggesting that information from few acoustic parameters suffice for recognizing complex sounds. We anticipate that future neurophysiological experiments in this paradigm may help elucidate how formants contribute to the recognition of sounds.

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In human speech and communication across various species, recognizing and categorizing sounds is fundamental for the selection of appropriate behaviors. However, how does the brain decide which action to perform based on sounds? We explored whether the supplementary motor area (SMA), responsible for linking sensory information to motor programs, also accounts for auditory-driven decision making. To this end, we trained two rhesus monkeys to discriminate between numerous naturalistic sounds and words learned as target (T) or non-target (nT) categories. We found that the SMA at single and population neuronal levels perform decision-related computations that transition from auditory to movement representations in this task. Moreover, we demonstrated that the neural population is organized orthogonally during the auditory and the movement periods, implying that the SMA performs different computations. In conclusion, our results suggest that the SMA integrates acoustic information in order to form categorical signals that drive behavior.

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Perceiving the temporal regularity in a sequence of repetitive sensory events facilitates the preparation and execution of relevant behaviors with tight temporal constraints. How we estimate temporal regularity from repeating patterns of sensory stimuli is not completely understood. We developed a decision-making task in which participants had to decide whether a train of visual, auditory, or tactile pulses, had a regular or an irregular temporal pattern. We tested the hypothesis that subjects categorize stimuli as irregular by accumulating the time differences between the predicted and observed times of sensory pulses defining a temporal rhythm. Results suggest that instead of waiting for a single large temporal deviation, participants accumulate timing-error signals and judge a pattern as irregular when the amount of evidence reaches a decision threshold. Model fits of bounded integration showed that this accumulation occurs with negligible leak of evidence. Consistent with previous findings, we show that participants perform better when evaluating the regularity of auditory pulses, as compared with visual or tactile stimuli. Our results suggest that temporal regularity is estimated by comparing expected and measured pulse onset times, and that each prediction error is accumulated towards a threshold to generate a behavioral choice.

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En este artículo de revisión abordamos el problema de la percepción de distancia durante la locomoción. La misma implica una construcción mental del entorno que nos rodea que debe ser realizada de una manera rápida y precisa, pues la información es crucial para poder interactuar correctamente con el ambiente y los objetos que se encuentran en él. En buena parte del tiempo nosotros y el mundo que nos rodea nos encontramos en un continuo movimiento relativo, por lo que nuestra experiencia perceptual estaría moldeada por las complejas interacciones entre la información provista por los sentidos y por la percepción del propio movimiento. El tratar de adquirir datos de la percepción de distancia con el observador en movimiento implica requerimientos diferentes a la situación cuando se encuentra estático. Ello lleva buscar soluciones y nuevas alternativas metodológicas. Esto es ejemplificado a partir de los trabajos experimentales realizados utilizando la cinta de correr como plataforma de investigación en campo abierto.

Neste artigo de revisão, abordamos o problema da percepção da distância durante a locomoção. Isto implica uma construção mental do ambiente que nos rodeia, que deve ser realizada de maneira rápida e precisa, pois a informação é crucial para poder interagir corretamente com o ambiente e com os objetos encontrados nele. Na maior parte do tempo, nós e o mundo à nossa volta estamos em um movimento relativo contínuo, sendo nossa experiência perceptiva moldada pelas complexas interações entre as informações fornecidas pelos sentidos e pela percepção do próprio movimento. Tentar adquirir dados de percepção de distância com o observador em movimento implica requisitos diferentes para a situação quando ela é estática. Isso leva à busca de soluções e novas alternativas metodológicas. Isso é exemplificado pelo trabalho experimental realizado com a esteira como plataforma de pesquisa em campo aberto.

In this review article we address the problem of distance perception during locomotion. It implies a mental construction of the environment that surrounds us that must be carried out in a fast and precise way, since this information is crucial to be able to correctly interact with the environment and the objects in it. In much of the time we and the world around us are in a continuous relative movement, so our perceptual experience would be shaped by the complex interactions between the information provided by the senses and by the perception of our movement itself. Trying to acquire distance perception data with the observer in motion implies different requirements to the situation when it is static. This leads to seeking solutions and new methodological alternatives. This is exemplified from the experimental work carried out using the treadmill as a research platform in the open field.

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Previous findings suggest a right hemispheric contribution to body image distortions only in women. Here we set out to replicate this finding and investigate whether the sex of the body image would play a role in this lateralization. We report here two experiments of body size estimation using the divided visual field methodology. In Experiment 1 we found no effect of visual field, participant sex, and body image sex. We discuss the results in terms of the androgynous-like stimuli appearance. In Experiment 2 we increased the dimorphism of body image stimuli. Surprisingly, we observed a different pattern. Both men and women overestimated the size of female models presented in both visual fields, but the size of male models was underestimated for presentations in the left visual field compared to presentations in the right visual field. We found no differences between men and women. Our results suggest that the differences in lateralization of body image distortions between men and women observed in previous studies can be attributed to the sex of the body image. To the best of our knowledge, this is the first study to show that the sex of the body image modulates lateralization and body image distortion.

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A medida de Sensibilidade ao Contraste (SC) de primeira ordem é frequentemente utilizada para avaliação da percepção espacial. Nosso objetivo foi desenvolver e validar um teste de SC de segunda ordem para aplicação clínica. Modificações metodológicas foram realizadas na rotina psicofísica para redução do tempo de testagem em um primeiro experimento, validamos a nova metodologia. Em um segundo experimento, valores de normalidade foram derivados do resultado de 16 participantes e foram testados nas mesmas condições do primeiro experimento. As medidas de validade foram obtidas por meio do Spearman-Brown Split-Half Reliability Coefficient para todas as frequências espaciais testadas (r> 0,90). O desenvolvimento e a validação deste novo experimento para as medidas de SC de segunda ordem permitirão avançar nos estudos dos mecanismos básicos da percepção de espaço para estímulos complexos, assim como a aplicação clínica em diversas doenças.

The first-order Contrast Sensitivity (SC) measure is often used to assess spatial perception. Our goal was to develop and validate a second-order SC test for clinical application. Methodological changes were made in the psychophysical routine to reduce testing time and in the first experiment we validated the new methodology. In a second experiment, normal values were derived from the result of sixteen participants who were tested under the same conditions as the first experiment. Validity measures were obtained using Spearman-Brown Split-Half Reliability Coefficient for all tested spatial frequencies (r> 0.90). The development and validation of this new experiment for second-order SC measures will allow to advance in the studies of the basic mechanisms of the perception of space for complex stimuli, as well as the clinical application in several diseases.

La medida de sensibilidad al contraste (SC) de primer orden se utiliza a menudo para evaluar la percepción espacial. Nuestro objetivo era desarrollar y validar una prueba SC de segundo orden para aplicación clínica. Se realizaron cambios metodológicos en la rutina psicofísica para reducir el tiempo de prueba y en el primer experimento validamos la nueva metodología. En un segundo experimento, los valores normales se derivaron del resultado de dieciséis participantes que fueron evaluados en las mismas condiciones que el primer experimento. Las medidas de validez se obtuvieron utilizando el coeficiente de confiabilidad de la mitad dividida de Spear-man-Brown para todas las frecuencias espaciales probadas (r> 0.90). El desarrollo y validación de este nuevo experimento para medidas CS de segundo orden permitirá avanzar en los estudios de los mecanismos básicos de percepción del espacio para estímulos complejos, así como la aplicación clínica en diversas enfermedades.

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Este artigo apresenta um estudo metodológico de um procedimento experimental com duas tarefas de processamento categórico auditivo para fala. Na tarefa de identificação, o participante ouve sons que variam em duração de VOT e é solicitado a identificar a que palavra correspondem. Na tarefa de discriminação, o participante deve indicar se dois estímulos de VOT adjacentes são iguais ou diferentes. As estratégias de análises de dados para caracterizar o grau de categorização são apresentadas e são discutidas possibilidades de uso do procedimento em estudos.

This article presents a methodological study of an experimental procedure with two tasks of categorical auditory processing for speech. In the identification task, the participant hears sounds that vary in VOT duration and is asked to identify which word they correspond to. In the discrimination task, the participant must indicate whether two adjacent VOT stimuli are the same or different. The data analysis strategies to characterize the degree of categorization are presented and possibilities of using the procedure in studies are discussed.

Este artículo presenta un estudio metodológico de un procedimiento experimental con dos tareas de procesamiento auditivo categórico para el habla. En la tarea de identificación, el participante escucha sonidos que varían en la duración del VOT y se le pide que identifique a qué palabra corresponden. En la tarea de discriminación, el participante debe indicar si dos estímulos VOT adyacentes son iguales o diferentes. Se presentan las estrategias de análisis de datos para caracterizar el grado de categorización y se discuten las posibilidades de utilizar el procedimiento en los estudios.

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A percepção de movimento é objeto de estudo da psicofísica, entretanto há poucos estudos em situações naturalísticas ou que utilizam veículos reais. Investigamos como as pessoas percebem a velocidade de veículos em situações naturais. Observadores estáticos foram solicitados a determinar a velocidade de um veículo real em movimento. Os resultados demonstraram acurácia nas estimativas das velocidades dos veículos, independente do sexo do participante e de possuir ou não habilitação. O expoente da função-potência associado a esta dimensão foi de 1,31, mostrando tendência à superestimativa com o aumento da velocidade física, indicando que não há linearidade na percepção de velocidades de veículos por observadores estáticos.

The perception of movement is an object of study of psychophysics, however there are few studies in naturalistic situations or using real vehicles. We investigated how people perceive vehicle speed in natural situations. Static observers were asked to determine the speed of a real moving vehicle. The results showed accuracy in the estimates of vehicle speeds, regardless of the participant's gender and whether or not they are licensed. The exponent of the power-function associated with this dimension was 1.31, showing a tendency to overestimate with increasing physical speed, indicating that there is no linearity in the perception of vehicle speeds by static observers

La percepción del movimiento es objeto de estudio de la psicofísica, sin embargo, existen pocos estudios en situaciones naturalistas o utilizando vehículos reales. Investigamos cómo personas perciben la velocidad del vehículo en situaciones naturales. Se pidió a observadores estáticos que determinaran la velocidad de vehículos en movimiento real. Los resultados mostraron precisión en las estimaciones de la velocidad, independientemente del género del participante y si tiene licencia o no. El exponente de la función de potencia asociado con esta dimensión fue 1.31, mostrando una tendencia a sobreestimar con el aumento de la velocidad física, lo que indica que no existe linealidad en la percepción de la velocidad del vehículo por parte de los observadores estáticos.

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PURPOSE: To access retinal straylight in a Brazilian sample and to compare it with European norms. METHODS: Absolute Straylight was assessed using C-Quant that uses an adaptive staircase based on a 2-Alternated Forced Choice task. A young (22.2 ± 2.4 yrs, n = 20) and an old group (53.8 ± 7.4 yrs, n = 21) of subjects were tested. All refractive errors were corrected in the C-Quant device, and no subjects had ocular diseases or vision-threatening conditions (e.g., diabetes, unregulated blood pressure, high intraocular pressure, visible cataract). Eighty-five percent of all subjects in each age group had dark-pigmented eyes. Each eye was tested 3 times, yielding 6 straylight values (s). Only data fulfilling C-Quant reliability criteria were included. RESULTS: There were no statistical differences between the three attempts on each eye (ANOVA, F = 0.993, p > 0.936) and between the two groups (ANOVA, F = 0.893, p > 0.725). Straylight values (s) were fit with an empirical equation to compare to European norms. There were no statistical differences between Brazilian straylight values and European norms for either young or old age groups (ANOVA, F = 5.114, p > 0.993). However, there was a tendency for our s values to be higher than the European norms, consistent with young Brazilian eyes having more light-scattering than age-matched European eyes. CONCLUSIONS: Consistent with European norms, light-scattering increases with age in the Brazilian sample. This increase is thought to be due, in large part, to age-related changes in lens structure and density. Although the differences between the populations are not significant, the tendency for Brazilian data to have higher s values than European values, especially at young subjects, is in the opposite direction from that expected from a dark-eyed population. This suggests the hypothesis that latitude-dependent (Sao Paulo, latitude 23° S, European latitudes between 40° N to 55° N) differences in the light environment could be associated with differences in s values.

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This study evaluated visual sensitivity to luminance contrast during a daily period. Twenty-eight young male adults (M = 24.85; SD = 2.4) with normal color vision and 20/20 visual acuity participated in this study. The circadian pattern was assessed using the Karolinska Sleepiness Scale (KSS), the Pittsburgh Sleep Quality Index (PSQI), and a sleep diary. To measure the luminance contrast, we used version 11.0 of the Metropsis software with sine-element frequency stimuli for spatial frequencies of 0.2, 0.6, 1, 3.1, 6.1, 8.8, 13.2, and 15.6 cycles per degree of visual angle (cpd). The stimuli were presented on a 19-inch color cathode ray tube (CRT) video monitor with a resolution of 1024 × 786 pixels, an update rate of 100 Hz, and a photopic luminance of 39.6 cd/m2. There was a significant difference in KSS on the weekdays [χ2(2) = 20.27; p = .001] and in the luminance contrast for frequencies of 13.2 cpd [χ2(2) = 8.27; p = .001] and 15.6 cpd [χ2(2) = 13.72; p = .041]. The results showed greater stability of the measurement during the afternoon and a reduction in the visual sensitivity in the high spatial frequencies during the night.

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