Asymmetry of Tactile Perception and Interhemispheric Interactions in Stutterers

The effect of inverse masking on the skin of the left and right hands and of bimanual reverse masking during coordinated work of both hands in stutterers was studied to detect the changes in cerebral asymmetry related to stuttering. The study showed that (1) asymmetry of tactile perception is absent in stutterers in the conditions of masking; it is supposed that when stuttering begins in early childhood, the formation of the hemispheric specialization in performing both sensory (all modalities) and speech functions is interrupted; (2) stuttering right-handers demonstrate a strongly levotropic nature of the interhemispheric interactions under conditions of bimanual masking, which testifies to a more considerable retardation of the perception of a test stimulus in the stutterers' left hemisphere under the influence of the masking stimulus in the right hemisphere than in right-handers with normal speech. It is assumed on this basis that stuttering begins because of the combination of symmetry and asymmetry in the interhemispheric relations. There is a hypothetical model that supposes that the phenomenon of stuttering is caused by two fundamental factors, namely, bilateral symmetry (existence of two identical speech centers in the right and left hemispheres) and a specific levotropic asymmetry of the interhemispheric relations, i.e., a more manifest influence of the right hemisphere on the left hemisphere in stutterers. This conditions the emergence of two identical speech impulses that appear with long intervals between them, which cause a dissonance in the functioning of the speech-forming apparatus.     

Auditory and Visual Interhemispheric Communication in Musicians and Non-Musicians

The corpus callosum (CC) is a brain structure composed of axon fibres linking the right and left hemispheres. Musical training is associated with larger midsagittal cross-sectional area of the CC, suggesting that interhemispheric communication may be faster in musicians. Here we compared interhemispheric transmission times (ITTs) for musicians and non-musicians. ITT was measured by comparing simple reaction times to stimuli presented to the same hemisphere that controlled a button-press response (uncrossed reaction time), or to the contralateral hemisphere (crossed reaction time). Both visual and auditory stimuli were tested. We predicted that the crossed-uncrossed difference (CUD) for musicians would be smaller than for non-musicians as a result of faster interhemispheric transfer times. We did not expect a difference in CUDs between the visual and auditory modalities for either musicians or non-musicians, as previous work indicates that interhemispheric transfer may happen through the genu of the CC, which contains motor fibres rather than sensory fibres. There were no significant differences in CUDs between musicians and non-musicians. However, auditory CUDs were significantly smaller than visual CUDs. Although this auditory-visual difference was larger in musicians than non-musicians, the interaction between modality and musical training was not significant. Therefore, although musical training does not significantly affect ITT, the crossing of auditory information between hemispheres appears to be faster than visual information, perhaps because subcortical pathways play a greater role for auditory interhemispheric transfer.     

Tumor Cell Identification in Ki-67 Images on Deep Learning

The proportion of cells staining for the nuclear antigen Ki-67 is an important predictive indicator for assessment of tumor cell proliferation and growth in routine pathological investigation. Instead of traditional scoring methods based on the experience of a trained laboratory scientist, deep learning approach can be automatically used to analyze the expression of Ki-67 as well. Deep learning based on convolutional neural networks (CNN) for image classification and single shot multibox detector (SSD) for object detection are used to investigate the expression of Ki-67 for assessment of biopsies from patients with breast cancer in this study. The results focus on estimating the probability heatmap of tumor cells using CNN with accuracy of 98% and detecting the tumor cells using SSD with accuracy of 90%. This deep learning framework will provide an objective basis for the malignant degree of breast tumors and be beneficial to the pathologists for fast and efficiently Ki-67 scoring.     

Images,Senses and Applications: Engaging Visual Anthropology

In this article I discuss how visual anthropology methods are advancing in a present-day environment where applied, activist, public and interdisciplinary anthropologies are increasingly central. In earlier work [Pink 2004 Pink , Sarah 2004 Applied Visual Anthropology, a guest edited issue of Visual Anthropology Review, 20(1) . [Google Scholar], 2006 2006 The Future of Visual Anthropology: Engaging the Senses . Oxford : Routledge . [Google Scholar], 2007a 2007a Visual Interventions: Applied Visual Anthropology . Oxford : Berghahn . [Google Scholar]] I outlined the field of an applied visual anthropology, and discussed the potential of visual methods and media in the production of a public anthropology [Pink 2006 2006 The Future of Visual Anthropology: Engaging the Senses . Oxford : Routledge . [Google Scholar]]. Here I build on this to suggest how recent visual anthropology practices might both contribute to and resolve issues relating to contemporary debates in applied and public anthropology and the relationship between scholarly research and social intervention.     

The Adaptive Potential of Adolescents in the North and Its Relation to Interhemispheric Functional Asymmetry

Sensorimotor asymmetry, physical development, annual increments in the body size, functional state and adaptive potential as expressed by circulatory indices, life index, and functional test results were evaluated in 142 healthy Nenets adolescents from a boarding school and 60 healthy Russian pupils. Dextral and sinistral phenotypes were represented unequally in the children of both groups; the former was more common among the Russians. The subjects' adaptive capacities depended on their sex and the predominance of particular signs of interhemispheric functional asymmetry.     

Cerebral Asymmetry of fMRI-BOLD Responses to Visual Stimulation

Hemispheric asymmetry of a wide range of functions is a hallmark of the human brain. The visual system has traditionally been thought of as symmetrically distributed in the brain, but a growing body of evidence has challenged this view. Some highly specific visual tasks have been shown to depend on hemispheric specialization. However, the possible lateralization of cerebral responses to a simple checkerboard visual stimulation has not been a focus of previous studies. To investigate this, we performed two sessions of blood-oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) in 54 healthy subjects during stimulation with a black and white checkerboard visual stimulus. While carefully excluding possible non-physiological causes of left-to-right bias, we compared the activation of the left and the right cerebral hemispheres and related this to grey matter volume, handedness, age, gender, ocular dominance, interocular difference in visual acuity, as well as line-bisection performance. We found a general lateralization of cerebral activation towards the right hemisphere of early visual cortical areas and areas of higher-level visual processing, involved in visuospatial attention, especially in top-down (i.e., goal-oriented) attentional processing. This right hemisphere lateralization was partly, but not completely, explained by an increased grey matter volume in the right hemisphere of the early visual areas. Difference in activation of the superior parietal lobule was correlated with subject age, suggesting a shift towards the left hemisphere with increasing age. Our findings suggest a right-hemispheric dominance of these areas, which could lend support to the generally observed leftward visual attentional bias and to the left hemifield advantage for some visual perception tasks.     

Working Images: Visual Research and Representation in Ethnography

Working Images: Visual Research and Representation in Ethnography . Sarah Pink, László Kürti, and Ana Isabel Afonso. New York: Routledge, 2004. 224 pp.     

Investigation of Congenital Myasthenia Reveals Functional Asymmetry of Invariant Acetylcholine Receptor (AChR) Cys-loop Aspartates

We identify two heteroallelic mutations in the acetylcholine receptor δ-subunit from a patient with severe myasthenic symptoms since birth: a novel δD140N mutation in the signature Cys-loop and a mutation in intron 7 of the δ-subunit gene that disrupts splicing of exon 8. The mutated Asp residue, which determines the disease phenotype, is conserved in all eukaryotic members of the Cys-loop receptor superfamily. Studies of the mutant acetylcholine receptor expressed in HEK 293 cells reveal that δD140N attenuates cell surface expression and apparent channel gating, predicting a reduced magnitude and an accelerated decay of the synaptic response, thus reducing the safety margin for neuromuscular transmission. Substituting Asn for Asp at equivalent positions in the α-, β-, and ϵ-subunits also suppresses apparent channel gating, but the suppression is much greater in the α-subunit. Mutant cycle analysis applied to single and pairwise mutations reveals that αAsp-138 is energetically coupled to αArg-209 in the neighboring pre-M1 domain. Our findings suggest that the conserved αAsp-138 and αArg-209 contribute to a principal pathway that functionally links the ligand binding and pore domains.     

Refractive Errors Affect the Vividness of Visual Mental Images

The hypothesis that visual perception and mental imagery are equivalent has never been explored in individuals with vision defects not preventing the visual perception of the world, such as refractive errors. Refractive error (i.e., myopia, hyperopia or astigmatism) is a condition where the refracting system of the eye fails to focus objects sharply on the retina. As a consequence refractive errors cause blurred vision.We subdivided 84 individuals according to their spherical equivalent refraction into Emmetropes (control individuals without refractive errors) and Ametropes (individuals with refractive errors). Participants performed a vividness task and completed a questionnaire that explored their cognitive style of thinking before their vision was checked by an ophthalmologist. Although results showed that Ametropes had less vivid mental images than Emmetropes this did not affect the development of their cognitive style of thinking; in fact, Ametropes were able to use both verbal and visual strategies to acquire and retrieve information. Present data are consistent with the hypothesis of equivalence between imagery and perception.     

基于Visual C#语言的DICOM标准医学图像的显示和实现

介绍DICOM3.0医学图像文件的格式和C#语言的特点,首次利用Visual C#语言对该标准的图像进行显示和处理,能够直接读取DICOM格式原始图像数据,并可批量转换成BMP等格式进行处理,此项工作可为医学图像处理研究及相关医学图像软件开发奠定基础。     

Metacognitive Confidence Increases with,but Does Not Determine,Visual Perceptual Learning

While perceptual learning increases objective sensitivity, the effects on the constant interaction of the process of perception and its metacognitive evaluation have been rarely investigated. Visual perception has been described as a process of probabilistic inference featuring metacognitive evaluations of choice certainty. For visual motion perception in healthy, naive human subjects here we show that perceptual sensitivity and confidence in it increased with training. The metacognitive sensitivity–estimated from certainty ratings by a bias-free signal detection theoretic approach–in contrast, did not. Concomitant 3Hz transcranial alternating current stimulation (tACS) was applied in compliance with previous findings on effective high-low cross-frequency coupling subserving signal detection. While perceptual accuracy and confidence in it improved with training, there were no statistically significant tACS effects. Neither metacognitive sensitivity in distinguishing between their own correct and incorrect stimulus classifications, nor decision confidence itself determined the subjects’ visual perceptual learning. Improvements of objective performance and the metacognitive confidence in it were rather determined by the perceptual sensitivity at the outset of the experiment. Post-decision certainty in visual perceptual learning was neither independent of objective performance, nor requisite for changes in sensitivity, but rather covaried with objective performance. The exact functional role of metacognitive confidence in human visual perception has yet to be determined.     

Left-Right Asymmetry Is Required for the Habenulae to Respond to Both Visual and Olfactory Stimuli

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Efficiency of the Human Visual System in Discrimination of Dynamic Images

The efficiency of the human visual system during the observation of motionless test objects with additive dynamic Gaussian quasi-white noise was studied. It was found that the relationship between the duration of presentation of the object and the efficiency in presence of dynamic noise has a maximum at 20 ms. The presence of this maximum is explained by the simultaneous effects of two factors: (1) the limited duration of accumulation of visual memory and (2) the time necessary to develop decision-making thresholds during recognition. It was also shown that absence of prior information about the position of the target object reduces the efficiency more than absence of prior information about the time of its appearance.     

Automated Identification of Filaments in Cryoelectron Microscopy Images

Since the foundation for the three-dimensional image reconstruction of helical objects from electron micrographs was laid more than 30 years ago, there have been sustained developments in specimen preparation, data acquisition, image analysis, and interpretation of results. However, the boxing of filaments in large numbers of images--one of the critical steps toward the reconstruction at high resolution--is still constrained by manual processing even though interactive interfaces have been built to aid the tedious and sometimes inaccurate boxing process. This article describes an accurate approach for automated detection of filamentous structures in low-contrast images acquired in defocus pairs using cryoelectron microscopy. The performance of the approach has been evaluated across various magnifications and at a series of defocus values using tobacco mosaic virus (TMV) preserved in vitreous ice as a test specimen. By integrating the proposed approach into our automated data acquisition and reconstruction system, we are now able to generate a three-dimensional map of TMV to approximately 10-A resolution within 24 h of inserting the specimen grid into the microscope.     

Unsupervised Learning of Cone Spectral Classes from Natural Images

The first step in the evolution of primate trichromatic color vision was the expression of a third cone class not present in ancestral mammals. This observation motivates a fundamental question about the evolution of any sensory system: how is it possible to detect and exploit the presence of a novel sensory class? We explore this question in the context of primate color vision. We present an unsupervised learning algorithm capable of both detecting the number of spectral cone classes in a retinal mosaic and learning the class of each cone using the inter-cone correlations obtained in response to natural image input. The algorithm''s ability to classify cones is in broad agreement with experimental evidence about functional color vision for a wide range of mosaic parameters, including those characterizing dichromacy, typical trichromacy, anomalous trichromacy, and possible tetrachromacy.