9 resultados para Visual perception in infants

em Universidade do Minho


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Immersive environments (IE) are being increasingly used in order to perform psychophysical experiments. The versatility in terms of stimuli presentation and control and the less time-consuming procedures are their greatest strengths. However, to ensure that IE results can be generalized to real world scenarios we must first provide evidence that performance in IE is quantitatively indistinguishable from performance in real-world. Our goal was to perceptually validate distance perception for CAVE-like IEs. Participants performed a Frontal Matching Distance Task (Durgin & Li, 2011) in three different conditions: real-world scenario (RWS); photorealistic IE (IEPH) and non-photorealistic IE (IENPH). Underestimation of distance was found across all the conditions, with a significant difference between the three conditions (Wilks’ Lambda = .38, F(2,134)= 110.8, p<.01, significant pairwise differences with p<.01). We found a mean error of 2.3 meters for the RWS, 5 meters for the IEPH, and of 6 meters for the IENPH in a pooled data set of 5 participants. Results indicate that while having a photorealistic IE with perspective and stereoscopic depth cues might not be enough to elicit a real-world performance in distance judgment tasks, nevertheless this type of environment minimizes the discrepancy between simulation and real-world when compared with non-photorealistic IEs.

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With the present study we aimed to analyze the relationship between infants' behavior and their visual evoked-potential (VEPs) response. Specifically, we want to verify differences regarding the VEP response in sleeping and awake infants and if an association between VEP components, in both groups, with neurobehavioral outcome could be identified. To do so, thirty-two full-term and healthy infants, approximately 1-month of age, were assessed through a VEP unpatterned flashlight stimuli paradigm, offered in two different intensities, and were assessed using a neurobehavioral scale. However, only 18 infants have both assessments, and therefore, these is the total included in both analysis. Infants displayed a mature neurobehavioral outcome, expected for their age. We observed that P2 and N3 components were present in both sleeping and awake infants. Differences between intensities were found regarding the P2 amplitude, but only in awake infants. Regression analysis showed that N3 amplitude predicted an adequate social interactive and internal regulatory behavior in infants who were awake during the stimuli presentation. Taking into account that social orientation and regulatory behaviors are fundamental keys for social-like behavior in 1-month-old infants, this study provides an important approach for assessing physiological biomarkers (VEPs) and its relation with social behavior, very early in postnatal development. Moreover, we evidence the importance of the infant's state when studying differences regarding visual threshold processing and its association with behavioral outcome.

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The dorsolateral prefrontal cortex (DLPFC) is involved in the cognitive appraisal and modulation of the pain experience. In this sham-controlled study, with healthy volunteers, we used bi-hemispheric transcranial direct current stimulation (tDCS) over the DLPFC to assess emotional reactions elicited by pain observation. Left-cathodal/right-anodal tDCS decreased valence and arousal evaluations compared to other tDCS conditions. Compared to sham condition, both left-cathodal/right-anodal and left-anodal/right-cathodal tDCS decreased hostility, sadness and self-pain perception. These decreased sensations after both active tDCS suggest a common role for left and right DLPFC in personal distress modulation. However, the differences in arousal and valence evaluations point to distinct roles of lateralized DLPFC in cognitive empathy, probably through distinct emotion regulation mechanisms.

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This study is intended to analyze (1) differences in infant temperament at 3 and 12 months according to infants' psychophysiological profiles: "withdrawn" "extroverted", and "underaroused" and (2) changes in infant temperament from 3 to 12 months, namely according to the infant psychophysiological profile and the quality of mother-infant interaction. Ninety-four 8-week-old infants were assessed using the Neonatal Behavioral Assessment Scale (NBAS, Brazelton & Nugent, 1995) and the Alarm Distress Baby Scale (ADBB, Guedeney & Fermanian, 2001). Saliva samples were collected at 8-12 weeks old, both before and after a routine inoculation for cortisol reactivity measurement. Mother-infant interaction was evaluated at 12-16 weeks, using the Global Rating Scales (GRS, Murray, Fiori-Cowley, Hooper, & Cooper, 1996). Mothers' reports on infant temperament at 3 and 12 months were collected using the Infant Behavior Questionnaire (IBQ, Rothbart, 1981). Significant differences in mothers' perception of infant temperament were found at both 3 and 12 months in infants with distinct psychophysiological profiles. Stability was observed in most of the temperament's dimensions from 3 to 12 months old; still, there were changes in mothers' perception of infant temperament in terms of level of distress, cuddliness, sadness and approach. Infant psychophysiological profile and mother-infant interaction both influence with the pattern of those changes. The results corroborate that infant's characteristics early in life as well as contextual factors influence with mothers' perception of infant temperament and with changes across the 1st year of life.

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Relatório de estágio de mestrado em Educação Pré-Escolar e Ensino do 1ºCiclo do Ensino Básico

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Purpose: The purpose of this study was to evaluate the effect of orthokeratology for different degrees of myopia correction in the relative location of tangential (FT) and sagittal (FS) power errors across the central 70 of the visual field in the horizontal meridian. Methods: Thirty-four right eyes of 34 patients with a mean age of 25.2 ± 6.4 years were fitted with Paragon CRT (Mesa, AZ) rigid gas permeable contact lenses to treat myopia (2.15 ± 1.26D, range: 0.88 to 5.25D). Axial and peripheral refraction were measured along the central 70 of the horizontal visual field with the Grand Seiko WAM5500 open-field auto-refractor. Spherical equivalent (M), as well as tangential (FT) and sagittal power errors (FS) were obtained. Analysis was stratified in three groups according to baseline spherical equivalent: Group 1 [MBaseline = 0.88 to 1.50D; n = 11], Group 2 [MBaseline = 1.51 to 2.49D; n = 11], and Group 3 [MBaseline = 2.50 to 5.25D; n = 12]. Results: Spherical equivalent was significantly more myopic after treatment beyond the central 40 of the visual field (p50.001). FT became significantly more myopic for all groups in the nasal and temporal retina with 25 (p 0.017), 30 (p 0.007) and 35 (p 0.004) of eye rotation. Myopic change in FS was less consistent, achieving only statistical significance for all groups at 35 in the nasal and temporal retina (p 0.045). Conclusions: Orthokeratology changes significantly FT in the myopic direction beyond the central 40 of the visual field for all degrees of myopia. Changes induced by orthokeratology in relative peripheral M, FT and FS with 35 of eye rotation were significantly correlated with axial myopia at baseline. Keywords: Field

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Dissertação de mestrado em Ciências da Comunicação (área de especialização em Audiovisuais e Multimédia)

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This study aims to (a) identify and profile groups of infants according to their behavioral and physiological characteristics, considering their neurobehavioral organization, social withdrawal behavior, and endocrine reactivity to stress, and to (b) analyze group differences in the quality of mother–infant interaction. Ninety seven 8-week-old infants were examined using the Neonatal Behavioral Assessment Scale and the Alarm Distress Baby Scale. Cortisol levels were measured both before and after routine inoculation between 8 and 12 weeks. At 12 to 16 weeks mother–infant interaction was assessed using the Global Rating Scales of Mother–Infant Interaction. Three groups of infants were identified: (a) ‘‘withdrawn’’; (b) ‘‘extroverted’’; (c) ‘‘underaroused.’’ Differences between them were found regarding both infant and mother behaviors in the interaction and the overall quality of mother–infant interaction. The identification of behavioral and physiological profiles in infants is an important step in the study of developmental pathways.