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In everyday life, we have no trouble categorizing objects varying in position, size, and orientation. Previous fMRI research shows that higher-level object processing regions in the human lateral occipital cortex may link object responses from different affine states (i.e., size and viewpoint) through a general linear mapping function capable of predicting responses to novel objects. In this study, we extended this approach to examine the mapping for both Euclidean (e.g., position and size) and non-Euclidean (e.g., image statistics and spatial frequency) transformations across the human ventral visual processing hierarchy, including areas V1, V2, V3, V4, ventral occipitotemporal cortex, and lateral occipitotemporal cortex. The predicted pattern generated from a linear mapping function could capture a significant amount of the changes associated with the transformations throughout the ventral visual stream. The derived linear mapping functions were not category independent as performance was better for the categories included than those not included in training and better between two similar versus two dissimilar categories in both lower and higher visual regions. Consistent with object representations being stronger in higher than in lower visual regions, pattern selectivity and object category representational structure were somewhat better preserved in the predicted patterns in higher than in lower visual regions. There were no notable differences between Euclidean and non-Euclidean transformations. These findings demonstrate a near-orthogonal representation of object identity and these nonidentity features throughout the human ventral visual processing pathway with these nonidentity features largely untangled from the identity features early in visual processing.SIGNIFICANCE STATEMENT Presently we still do not fully understand how object identity and nonidentity (e.g., position, size) information are simultaneously represented in the primate ventral visual system to form invariant representations. Previous work suggests that the human lateral occipital cortex may be linking different affine states of object representations through general linear mapping functions. Here, we show that across the entire human ventral processing pathway, we could link object responses in different states of nonidentity transformations through linear mapping functions for both Euclidean and non-Euclidean transformations. These mapping functions are not identity independent, suggesting that object identity and nonidentity features are represented in a near rather than a completely orthogonal manner.
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Mapeo Encefálico , Lóbulo Occipital/fisiología , Reconocimiento Visual de Modelos/fisiología , Lóbulo Temporal/fisiología , Corteza Visual/fisiología , Vías Visuales/fisiología , Adolescente , Adulto , Animales , Reconocimiento Facial/fisiología , Femenino , Artículos Domésticos , Humanos , Imagen por Resonancia Magnética , Masculino , Adulto JovenRESUMEN
Over recent years, there has been an explosion of digital technologies and infrastructure, and many biomedical education contexts have taken advantage of these new tools and platforms for teaching and learning visualisation practices. However, there are uncertainties, concerns, and debates in the literature, regarding the impact of digital technology on biomedical visualisation, and education more broadly. In this discussion paper, a multimodal social semiotics perspective is applied to examining visual representations, and the visual language we use to make meaning with these representations, in four different ways. Firstly, in terms of the function, role, and positionality of visual representations within the biomedical sciences. Secondly, within the context of a disciplinary Discourse, wherein visual language functions as just one of many socially specific languages, or modes, such as the written, verbal, and symbolic modes, and through which we animate the discourse and make disciplinary meaning. Thirdly, consideration is given to the meaning-making affordances and limitations of biomedical visualisation practices, affirming that no single mode or media is superior and that multimodal integration is a necessity. Finally, there is a discussion of the approaches to teaching and learning for the acquisition of a disciplinary Discourse, which highlights a need to focus on explicating the hidden curriculum. This discussion presents a perspective that offers some valuable insights into the uncertainties expressed in the literature and empowers educators with some productive pedagogical strategies.
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Educación Médica , Aprendizaje , Computadores , CurriculumRESUMEN
Human ventral temporal cortex (VTC) is critical for visual recognition. It is thought that this ability is supported by large-scale patterns of activity across VTC that contain information about visual categories. However, it is unknown how category representations in VTC are organized at the submillimeter scale and across cortical depths. To fill this gap in knowledge, we measured BOLD responses in medial and lateral VTC to images spanning 10 categories from five domains (written characters, bodies, faces, places, and objects) at an ultra-high spatial resolution of 0.8 mm using 7 Tesla fMRI in both male and female participants. Representations in lateral VTC were organized most strongly at the general level of domains (e.g., places), whereas medial VTC was also organized at the level of specific categories (e.g., corridors and houses within the domain of places). In both lateral and medial VTC, domain-level and category-level structure decreased with cortical depth, and downsampling our data to standard resolution (2.4 mm) did not reverse differences in representations between lateral and medial VTC. The functional diversity of representations across VTC partitions may allow downstream regions to read out information in a flexible manner according to task demands. These results bridge an important gap between electrophysiological recordings in single neurons at the micron scale in nonhuman primates and standard-resolution fMRI in humans by elucidating distributed responses at the submillimeter scale with ultra-high-resolution fMRI in humans.SIGNIFICANCE STATEMENT Visual recognition is a fundamental ability supported by human ventral temporal cortex (VTC). However, the nature of fine-scale, submillimeter distributed representations in VTC is unknown. Using ultra-high-resolution fMRI of human VTC, we found differential distributed visual representations across lateral and medial VTC. Domain representations (e.g., faces, bodies, places, characters) were most salient in lateral VTC, whereas category representations (e.g., corridors/houses within the domain of places) were equally salient in medial VTC. These results bridge an important gap between electrophysiological recordings in single neurons at a micron scale and fMRI measurements at a millimeter scale.
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Mapeo Encefálico/métodos , Imagen por Resonancia Magnética/métodos , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/fisiología , Adulto , Simulación por Computador , Fenómenos Electrofisiológicos , Reconocimiento Facial/fisiología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Modelos Lineales , Masculino , Estimulación Luminosa , Desempeño Psicomotor , Lectura , Reconocimiento en Psicología/fisiología , Corteza Visual/diagnóstico por imagen , Corteza Visual/fisiologíaRESUMEN
The brain actively represents incoming information, but these representations are only useful to the extent that they flexibly reflect changes in the environment. How does the brain transform representations across changes, such as in size or viewing angle? We conducted a fMRI experiment and a magnetoencephalography experiment in humans (both sexes) in which participants viewed objects before and after affine viewpoint changes (rotation, translation, enlargement). We used a novel approach, representational transformation analysis, to derive transformation functions that linked the distributed patterns of brain activity evoked by an object before and after an affine change. Crucially, transformations derived from one object could predict a postchange representation for novel objects. These results provide evidence of general operations in the brain that are distinct from neural representations evoked by particular objects and scenes.SIGNIFICANCE STATEMENT The dominant focus in cognitive neuroscience has been on how the brain represents information, but these representations are only useful to the extent that they flexibly reflect changes in the environment. How does the brain transform representations, such as linking two states of an object, for example, before and after an object undergoes a physical change? We used a novel method to derive transformations between the brain activity evoked by an object before and after an affine viewpoint change. We show that transformations derived from one object undergoing a change generalized to a novel object undergoing the same change. This result shows that there are general perceptual operations that transform object representations from one state to another.
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Reconocimiento Visual de Modelos/fisiología , Corteza Visual/fisiología , Mapeo Encefálico , Femenino , Humanos , Imagen por Resonancia Magnética , Magnetoencefalografía , Masculino , Estimulación Luminosa/métodosRESUMEN
Discovering the visual features and representations used by the brain to recognize objects is a central problem in the study of vision. Recently, neural network models of visual object recognition, including biological and deep network models, have shown remarkable progress and have begun to rival human performance in some challenging tasks. These models are trained on image examples and learn to extract features and representations and to use them for categorization. It remains unclear, however, whether the representations and learning processes discovered by current models are similar to those used by the human visual system. Here we show, by introducing and using minimal recognizable images, that the human visual system uses features and processes that are not used by current models and that are critical for recognition. We found by psychophysical studies that at the level of minimal recognizable images a minute change in the image can have a drastic effect on recognition, thus identifying features that are critical for the task. Simulations then showed that current models cannot explain this sensitivity to precise feature configurations and, more generally, do not learn to recognize minimal images at a human level. The role of the features shown here is revealed uniquely at the minimal level, where the contribution of each feature is essential. A full understanding of the learning and use of such features will extend our understanding of visual recognition and its cortical mechanisms and will enhance the capacity of computational models to learn from visual experience and to deal with recognition and detailed image interpretation.
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Redes Neurales de la Computación , Reconocimiento Visual de Modelos/fisiología , Visión Ocular/fisiología , Percepción Visual/fisiología , Encéfalo/fisiología , Humanos , Modelos Neurológicos , Red Nerviosa/fisiología , Estimulación Luminosa , Psicofísica/métodos , Corteza Visual/fisiología , Vías Visuales/fisiologíaRESUMEN
Online dating has become increasingly popular among older adults following broader social media adoption patterns. The current study examined the visual representations of people on 39 dating sites intended for the older population, with a particular focus on the visualization of the intersection between age and gender. All 39 dating sites for older adults were located through the Google search engine. Visual thematic analysis was performed with reference to general, non-age-related signs (e.g., facial expression, skin color), signs of aging (e.g., perceived age, wrinkles), relational features (e.g., proximity between individuals), and additional features such as number of people presented. The visual analysis in the present study revealed a clear intersection between ageism and sexism in the presentation of older adults. The majority of men and women were smiling and had a fair complexion, with light eye color and perceived age of younger than 60. Older women were presented as younger and wore more cosmetics as compared with older men. The present study stresses the social regulation of sexuality, as only heterosexual couples were presented. The narrow representation of older adults and the anti-aging messages portrayed in the pictures convey that love, intimacy, and sexual activity are for older adults who are "forever young."
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Envejecimiento/psicología , Internet , Relaciones Interpersonales , Autoimagen , Identificación Social , Publicidad , Anciano , Ageísmo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Medios de Comunicación Sociales , EstereotipoRESUMEN
Landy and Goldstone (2007a, 2010) demonstrated that an explicit rule, operator precedence for simple arithmetic expressions, is enforced in part by perceptual processes like unit formation and attention. When perceptual grouping competes with operator precedence, errors increase. We replicated this result (Exp. 1) and investigated whether perceptual grouping effects persist when the visual stimulus is presented briefly and then masked (Exp. 2) and when verbal recoding is encouraged through vocal expression (Exp. 3). We found that perceptual-grouping effects persisted in the masking condition, suggesting that the mental representations of arithmetic expressions retain visuospatial characteristics. Similarly, verbalization of the expressions did not eliminate perceptual-grouping effects, suggesting that participants were not verbally recoding. In sum, the persistent effects of unit formation and spatial attention emphasize the importance of perceptual processing in the development of human expertise in this domain.
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Atención/fisiología , Percepción Espacial/fisiología , Percepción Visual/fisiología , Adulto , Humanos , Conceptos Matemáticos , Adulto JovenRESUMEN
A transition to a bio-based economy will affect society and requires collective action from a broad range of stakeholders. This includes the public, who are largely unaware of this transition. For meaningful public engagement people's emotional viewpoints play an important role. However, what the public's emotions about the transition are and how they can be taken into account is underexposed in public engagement literature and practice. This article aims to unravel the public's emotional views of the bio-based economy as a starting point for public engagement. Using Q methodology with visual representations of a bio-based economy we found four emotional viewpoints: (1) compassionate environmentalist, (2) principled optimist, (3) hopeful motorist and (4) cynical environmentalist. These provide insight into the distinct and shared ways through which members of the public connect with the transition. Implications for public engagement are discussed.
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Actitud , Comunicación , Conservación de los Recursos Naturales/economía , Emociones , Opinión Pública , Conservación de los Recursos Naturales/tendencias , Humanos , CienciaRESUMEN
When watching physical events, infants bring to bear prior knowledge about objects and readily detect changes that contradict physical rules. Here we investigate the possibility that scene gist may affect infants, as it affects adults, when detecting changes in everyday scenes. In Experiment 1, 15-month-old infants missed a perceptually salient change that preserved the gist of a generic outdoor scene; the same change was readily detected if infants had insufficient time to process the display and had to rely on perceptual information for change detection. In Experiment 2, 15-month-olds detected a perceptually subtle change that preserved the scene gist but violated the rule of object continuity, suggesting that physical rules may overpower scene gist in infants' change detection. Finally, Experiments 3 and 4 provided converging evidence for the effects of scene gist, showing that 15-month-olds missed a perceptually salient change that preserved the gist and detected a perceptually subtle change that disrupted the gist. Together, these results suggest that prior knowledge, including scene knowledge and physical knowledge, affects the process by which infants maintain their representations of everyday scenes.
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Atención , Psicología Infantil , Reconocimiento en Psicología , Percepción Visual , Femenino , Humanos , Lactante , Masculino , Tiempo de ReacciónRESUMEN
Previous studies, using the Continuous Flash Suppression (CFS) paradigm, observed that (Western) university students are better able to detect otherwise invisible pictures of objects when they are presented with the corresponding spoken word shortly before the picture appears. Here we attempted to replicate this effect with non-Western university students in Goa (India). A second aim was to explore the performance of (non-Western) meditators practicing Sudarshan Kriya Yoga in Goa in the same task. Some previous literature suggests that meditators may excel in some tasks that tap visual attention, for example by exercising better endogenous and exogenous control of visual awareness than non-meditators. The present study replicated the finding that congruent spoken cue words lead to significantly higher detection sensitivity than incongruent cue words in non-Western university students. Our exploratory meditator group also showed this detection effect but both frequentist and Bayesian analyses suggest that the practice of meditation did not modulate it. Overall, our results provide further support for the notion that spoken words can activate low-level category-specific visual features that boost the basic capacity to detect the presence of a visual stimulus that has those features. Further research is required to conclusively test whether meditation can modulate visual detection abilities in CFS and similar tasks.
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Estudiantes , Yoga , Humanos , Yoga/psicología , Masculino , Femenino , Adulto Joven , Adulto , Estudiantes/psicología , Percepción Visual/fisiología , Atención/fisiología , Estimulación Luminosa/métodos , Percepción del Habla/fisiología , Meditación/métodos , Meditación/psicología , Señales (Psicología) , AdolescenteRESUMEN
Labelling medical images is an arduous and costly task that necessitates clinical expertise and large numbers of qualified images. Insufficient samples can lead to underfitting during training and poor performance of supervised learning models. In this study, we aim to develop a SimCLR-based semi-supervised learning framework to classify colorectal neoplasia based on the NICE classification. First, the proposed framework was trained under self-supervised learning using a large unlabelled dataset; subsequently, it was fine-tuned on a limited labelled dataset based on the NICE classification. The model was evaluated on an independent dataset and compared with models based on supervised transfer learning and endoscopists using accuracy, Matthew's correlation coefficient (MCC), and Cohen's kappa. Finally, Grad-CAM and t-SNE were applied to visualize the models' interpretations. A ResNet-backboned SimCLR model (accuracy of 0.908, MCC of 0.862, and Cohen's kappa of 0.896) outperformed supervised transfer learning-based models (means: 0.803, 0.698, and 0.742) and junior endoscopists (0.816, 0.724, and 0.863), while performing only slightly worse than senior endoscopists (0.916, 0.875, and 0.944). Moreover, t-SNE showed a better clustering of ternary samples through self-supervised learning in SimCLR than through supervised transfer learning. Compared with traditional supervised learning, semi-supervised learning enables deep learning models to achieve improved performance with limited labelled endoscopic images.
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Drawing is regarded as a promising strategy for children's learning, which has greatly been supported by research using science texts as learning materials. To shed light on the benefit of drawing on children's text-based learning in humanities, two classes of 86 grade 5 children were required to learn an ancient Chinese poem in an actual classroom setting, either by drawing a visual picture illustrating the poem or by reading repeatedly at their own pace as usual. Data analyses were conducted using (generalized) linear mixed-effects models. The results indicated that children who were allowed to generate a drawing during learning showed better learning performance of the entire poem than children who were allowed to read repeatedly regarding the delayed posttest rather than the immediate posttest. Besides, children in the drawing group reported a higher level of learning motivation than those in the reading group. We argue that the generative drawing effect can be tentatively extended to ancient Chinese poetry education.
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Aprendizaje , Niño , Humanos , Motivación , Lectura , Poesía como Asunto , ArteRESUMEN
Visual perception is the product of serial hierarchical processing, parallel processing, and remapping on a dynamic network involving several topographically organized cortical visual areas. Here, we will focus on the topographical organization of cortical areas and the different kinds of visual maps found in the primate brain. We will interpret our findings in light of a broader representational framework for perception. Based on neurophysiological data, our results do not support the notion that vision can be explained by a strict representational model, where the objective visual world is faithfully represented in our brain. On the contrary, we find strong evidence that vision is an active and constructive process from the very initial stages taking place in the eye and from the very initial stages of our development. A constructive interplay between perceptual and motor systems (e.g., during saccadic eye movements) is actively learnt from early infancy and ultimately provides our fluid stable visual perception of the world.
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Movimientos Sacádicos , Percepción Visual , Animales , Percepción Visual/fisiología , Encéfalo , Primates , Mapeo EncefálicoRESUMEN
Visual literacy, which is the ability to effectively identify, interpret, evaluate, use, and create images and visual media, is an important aspect of science literacy. As molecular processes are not directly observable, researchers and educators rely on visual representations (e.g., drawings) to communicate ideas in biology. How learners interpret and organize those numerous diagrams is related to their underlying knowledge about biology and their skills in visual literacy. Furthermore, it is not always obvious how and why learners interpret diagrams in the way they do (especially if their interpretations are unexpected), as it is not possible to "see" inside the minds of learners and directly observe the inner workings of their brains. Hence, tools that allow for the investigation of visual literacy are needed. Here, we present a novel card-sorting task based on visual literacy skills to investigate how learners interpret and think about DNA-based concepts. We quantified differences in performance between groups of varying expertise and in pre- and postcourse settings using percentages of expected card pairings and edit distance to a perfect sort. Overall, we found that biology experts organized the visual representations based on deep conceptual features, while biology learners (novices) more often organized based on surface features, such as color and style. We also found that students performed better on the task after a course in which molecular biology concepts were taught, suggesting the activity is a useful and valid tool for measuring knowledge. We have provided the cards to the community for use as a classroom activity, as an assessment instrument, and/or as a useful research tool to probe student ideas about molecular biology.
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Current representation learning methods in Spiking Neural Networks (SNNs) rely on rate-based encoding, resulting in high spike counts, increased energy consumption, and slower information transmission. In contrast, our proposed method, Weight-Temporally Coded Representation Learning (W-TCRL), utilizes temporally coded inputs, leading to lower spike counts and improved efficiency. To address the challenge of extracting representations from a temporal code with low reconstruction error, we introduce a novel Spike-Timing-Dependent Plasticity (STDP) rule. This rule enables stable learning of relative latencies within the synaptic weight distribution and is locally implemented in space and time, making it compatible with neuromorphic processors. We evaluate the performance of W-TCRL on the MNIST and natural image datasets for image reconstruction tasks. Our results demonstrate relative improvements of 53% for MNIST and 75% for natural images in terms of reconstruction error compared to the SNN state of the art. Additionally, our method achieves significantly higher sparsity, up to 900 times greater, when compared to related work. These findings emphasize the efficacy of W-TCRL in leveraging temporal coding for enhanced representation learning in Spiking Neural Networks.
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Reverse correlation (RC) method has been recently used to visualize mental representations of self. Previous studies have mainly examined the relationship between psychological aspects measured by self-reports and classification images of self (self-CIs), which are visual proxies of self-image generated through the RC method. In Experiment 1 (N = 118), to extend the validity of self-CIs, we employed social evaluation on top of self-reports as criterion variables and examined the relationship between self-CIs and social evaluation provided by clinical psychologists. Experiment 1 revealed that the valence ratings of self-CIs evaluated by independent raters predicted social evaluation after controlling for the effects of self-reported self-esteem and extraversion. Furthermore, in Experiment 2 (N = 127), we examined whether a computational scoring method - a method to assess self-CIs without employing independent raters - could be applied to evaluate the valence of participants' self-CIs. Experiment 2 found that the computational scores of self-CIs were comparable to independent valence ratings of self-CIs. We provide evidence that self-CIs can add independent information to self-reports in predicting social evaluation. We also suggest that the computational scoring method can complement the independent rating process of self-CIs. Overall, our findings reveal that self-CIs are a valid and useful tool to examine self-image more profoundly.
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One of the key challenges in implementing reinforcement learning methods for real-world robotic applications is the design of a suitable reward function. In field robotics, the absence of abundant datasets, limited training time, and high variation of environmental conditions complicate the task further. In this paper, we review reward learning techniques together with visual representations commonly used in current state-of-the-art works in robotics. We investigate a practical approach proposed in prior work to associate the reward with the stage of the progress in task completion based on visual observation. This approach was demonstrated in controlled laboratory conditions. We study its potential for a real-scale field application, autonomous pile loading, tested outdoors in three seasons: summer, autumn, and winter. In our framework, the cumulative reward combines the predictions about the process stage and the task completion (terminal stage). We use supervised classification methods to train prediction models and investigate the most common state-of-the-art visual representations. We use task-specific contrastive features for terminal stage prediction.
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Visual attention allows observers to change the influence of different parts of a visual scene on their behavior, suggesting that information can be flexibly shared between visual cortex and neurons involved in decision making. We investigated the neural substrate of flexible information routing by analyzing the activity of populations of visual neurons in the medial temporal area (MT) and oculo-motor neurons in the superior colliculus (SC) while rhesus monkeys switched spatial attention. We demonstrated that attention increases the efficacy of visuomotor communication: trial-to-trial variability in SC population activity could be better predicted by the activity of the MT population (and vice versa) when attention was directed toward their joint receptive fields. Surprisingly, this improvement in prediction was not explained by changes in the dimensionality of the shared subspace or in the magnitude of local or shared pairwise noise correlations. These results lay a foundation for future theoretical and experimental studies into how visual attention can flexibly change information flow between sensory and decision neurons.
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Corteza Visual , Animales , Macaca mulatta , Neuronas/fisiología , Estimulación Luminosa , Colículos Superiores , Corteza Visual/fisiologíaRESUMEN
Intergroup biases shape most aspects of person construal, including lower-level visual representations of group members' faces. Specifically, ingroup members' faces tend to be represented more positively than outgroup members' faces. Here, we used a reverse-correlation paradigm to test whether engaging in perspective taking (i.e., actively imagining another person's mental states) can reduce these biased visual representations. In an initial image-generation experiment, participants were randomly assigned to a minimal group and then composed a narrative essay about an ingroup or an outgroup target person, either while adopting the person's perspective or while following control instructions. Afterward, they generated an image of the person's face in a reverse-correlation image-classification task. Subsequent image-assessment experiments using an explicit rating task, a sequential priming task, and an economic trust game with separate samples of participants revealed that ingroup faces elicited more likability and trustworthiness than did outgroup faces. Importantly, this pattern of intergroup bias was consistently weaker in faces created by perspective takers. Additional image-assessment experiments identified the mouth (i.e., smiling cues) as a critical facial region wherein the interactive effects of group membership and perspective taking emerged. These findings provide initial evidence that perspective taking may be an effective strategy for attenuating, though not for eliminating, intergroup biases in visual representations of what group members look like.
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Cara , Confianza , Sesgo , HumanosRESUMEN
European local authorities increasingly use social media to present services and activities organized for citizens living in the particular area. Previous studies found that authority-managed social media visually depicted older adults as being active, sociable, happy, and physically capable, reflecting the normative "third age" representation. Yet few studies to date have examined how local authorities produce the photos of older adults for social media posting. Drawing on semi-structured interviews with communication officers in a Swedish municipality, the purpose of this study is to investigate the production process for social media photos of older adults within local authorities from an institutional logics perspective. The analysis illustrates that communication officers strive to create a good image of the municipality and its services, follow municipal policy and EU law on data protection, seek photos through particular sources, adjust to and develop photographic standards of good photos, and endeavor to promote social media engagement in the photos. These motives and work practices of communication officers contribute to the visual representations of older adults as engaging in municipal services, being socially active, and staying physically capable. The analysis also indicates that both social media and bureaucratic logics encourage officers to produce photos of older adults that highlight the bright side of later life. The findings contribute to previous studies on online representations of older adults generated by local authorities, by showing how the third age representation may come about in practice, and which logics may influence officers to generate such representation. Furthermore, the knowledge provided could be used as a basis for assessment and improvement on authorities' production for social media photos of older adults, which in turn contributes to more diverse and thoughtful representations of older adults and later life in authority-managed social media.