The role of semantic interference in limiting memory for the details of visual scenes

Many studies suggest a large capacity memory for briefly presented pictures of whole scenes. At the same time, visual working memory (WM) of scene elements is limited to only a few items. We examined the role of retroactive interference in limiting memory for visual details. Participants viewed a scene for 5?s and then, after a short delay containing either a blank screen or 10 distracter scenes, answered questions about the location, color, and identity of objects in the scene. We found that the influence of the distracters depended on whether they were from a similar semantic domain, such as "kitchen" or "airport." Increasing the number of similar scenes reduced, and eventually eliminated, memory for scene details. Although scene memory was firmly established over the initial study period, this memory was fragile and susceptible to interference. This may help to explain the discrepancy in the literature between studies showing limited visual WM and those showing a large capacity memory for scenes.

Dorsal and ventral stream mediated visual processing in genetic subtypes of Prader-Willi syndrome

Previous work has suggested that there are specific deficits in dorsal stream processing in a variety of developmental disorders. Prader-Willi syndrome (PWS) is associated with two main genetic subtypes, deletion and disomy. Relative strengths in visual processing are shown in PWS, although these strengths may be specific to the deletion subtype. We investigated visual processing in PWS using an adapted Simon task which contrasted location (dorsal stream) and shape identity (ventral stream) tasks. Compared to a group of typically developing children, children with PWS deletion showed a greater degree of impairment in the dorsal stream task than in the ventral stream task, a pattern similar to that shown in a group of boys with Fragile-X syndrome. When matched on a measure of non-verbal ability, children with PWS disomy showed the opposite pattern with better performance in the location compared to the shape task, although these task performance asymmetries may have been linked to executive control processes. It is proposed that children with PWS deletion show a relative strength in visual processing in the ventral stream along with a specific deficit in dorsal stream processing. In contrast, children with PWS disomy show neither effect. (C) 2009 Published by Elsevier Ltd.

Variants in the 1q21 risk region are associated with a visual endophenotype of autism and schizophrenia

Deficits in sensitivity to visual stimuli of low spatial frequency and high temporal frequency (so-called frequency-doubled gratings) have been demonstrated both in schizophrenia and in autism spectrum disorder (ASD). Such basic perceptual functions are ideal candidates for molecular genetic study, because the underlying neural mechanisms are well characterized; but they have sometimes been overlooked in favor of cognitive and neurophysiological endophenotypes, for which neural substrates are often unknown. Here, we report a genome-wide association study of a basic visual endophenotype associated with psychological disorder. Sensitivity to frequency-doubled gratings was measured in 1060 healthy young adults, and analyzed for association with genotype using linear regression at 642758 single nucleotide polymorphism (SNP) markers. A significant association (P=7.9×10) was found with the SNP marker rs1797052, situated in the 5′-untranslated region of PDZK1; each additional copy of the minor allele was associated with an increase in sensitivity equivalent to more than half a standard deviation. A permutation procedure, which accounts for multiple testing, showed that the association was significant at the α=0.005 level. The region on chromosome 1q21.1 surrounding PDZK1 is an established susceptibility locus both for schizophrenia and for ASD, mirroring the common association of the visual endophenotype with the two disorders. PDZK1 interacts with N-methyl-d-aspartate receptors and neuroligins, which have been implicated in the etiologies of schizophrenia and ASD. These findings suggest that perceptual abnormalities observed in two different disorders may be linked by common genetic elements. © 2013 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Uniformity of visual acuity measures in published studies

PURPOSE. To investigate the methods used in contemporary ophthalmic literature to designate visual acuity (VA). METHODS. Papers in all 2005 editions of five ophthalmic journals were considered. Papers were included if (1) VA, vision, or visual function was mentioned in the abstract and (2) if the study involved age-related macular degeneration, cataract, or refractive surgery. If a paper was selected on the basis of its abstract, the full text of the paper was examined for information on the method of refractive correction during VA testing, type of chart used to measure VA, specifics concerning chart features, testing protocols, and data analysis and means of expressing VA in results. RESULTS. One hundred twenty-eight papers were included. The most common type of charts used were described as logMAR-based. Although most (89.8%) of the studies reported on the method of refractive correction during VA testing, only 58.6% gave the chart design, and less than 12% gave any information whatsoever on chart features or measurement procedures used. CONCLUSIONS. The methods used and the approach to analysis were rarely described in sufficient detail to allow others to replicate the study being reported. Sufficient detail should be given on VA measurement to enable others to duplicate the research. The authors suggest that charts adhering to Bailey-Lovie design principles always be used to measure vision in prospective studies and their use encouraged in clinical settings. The distinction between the terms logMAR, an acuity notation, and Bailey-Lovie or ETDRS as chart types should be adhered to more strictly. Copyright © Association for Research in Vision and Ophthalmology.

Change of visual acuity recording methods in clinical studies across the years

Purpose: To report any differences in the visual acuity (VA) recording method used in peer-reviewed ophthalmology clinical studies over the past decade. Methods: We reviewed the method of assessing and reporting VA in 160 clinical studies from 2 UK and 2 US peer-reviewed journals, published in 1994 and 2004. Results: The method used to assess VA was specified in 62.5% of UK-published and 60% of US-published papers. In the results sections of the UK publications the VA measurements presented were Snellen acuity (n = 58), logMAR acuity (n = 20) and symbol acuity (n = 1). Similarly in the US publications the VA was recorded in the results section using Snellen acuity (n = 60) and logMAR acuity (n = 14). Overall 10% of the authors appeared to convert Snellen acuity measurements to logMAR format. Five studies (3%) chose to express Snellen-type acuities in decimal form, a method which can easily lead to confusion given the increased use of logMAR scoring systems. Conclusion: The authors recommend that to ensure comparable visual results between studies and different study populations it would be useful if clinical scientists worked to standardized VA testing protocols and reported results in a manner consistent with the way in which they are measured. Copyright © 2008 S. Karger AG.

Getting In and Getting On? The Experiences of Young People with Visual Impairments and Hearing Impairments in Third-Level Education

Young disabled people continue to be under-represented throughout further and higher education settings. Drawing on Pierre Bourdieu’s social theory of habitus, capital and field, this paper explores the practices of domination and oppression that have made it difficult for young people with visual impairments and hearing impairments to participate in third-level education on the same basis as non-disabled people. Twenty young people with hearing impairments and visual impairments were interviewed about their educational experiences. In addition, 31 interviews were conducted with third-level education providers, policy-makers and non-governmental organisations. This article has two aims: firstly, to critically examine the experiences of young people with hearing impairments and visual impairments in accessing and engaging with support provisions in further and higher education settings; and secondly, to identify and explore the diversity of ways in which these young people have managed and responded to the practices they have encountered. This article emphasises the journey from ability to dis-ability that young people with hearing and visual impairments experience in their quest for educational achievement. The ambiguities of “inclusion”, “widening participation” and “support” are highlighted and critiqued for their extensive failure to challenge taken-for-granted discourses.

Adaptive NormalHedge for robust visual tracking

In this paper, we propose a novel visual tracking framework, based on a decision-theoretic online learning algorithm namely NormalHedge. To make NormalHedge more robust against noise, we propose an adaptive NormalHedge algorithm, which exploits the historic information of each expert to perform more accurate prediction than the standard NormalHedge. Technically, we use a set of weighted experts to predict the state of the target to be tracked over time. The weight of each expert is online learned by pushing the cumulative regret of the learner towards that of the expert. Our simulation experiments demonstrate the effectiveness of the proposed adaptive NormalHedge, compared to the standard NormalHedge method. Furthermore, the experimental results of several challenging video sequences show that the proposed tracking method outperforms several state-of-the-art methods.

Robust visual tracking using structurally random projection and weighted least squares

Sparse representation based visual tracking approaches have attracted increasing interests in the community in recent years. The main idea is to linearly represent each target candidate using a set of target and trivial templates while imposing a sparsity constraint onto the representation coefficients. After we obtain the coefficients using L1-norm minimization methods, the candidate with the lowest error, when it is reconstructed using only the target templates and the associated coefficients, is considered as the tracking result. In spite of promising system performance widely reported, it is unclear if the performance of these trackers can be maximised. In addition, computational complexity caused by the dimensionality of the feature space limits these algorithms in real-time applications. In this paper, we propose a real-time visual tracking method based on structurally random projection and weighted least squares techniques. In particular, to enhance the discriminative capability of the tracker, we introduce background templates to the linear representation framework. To handle appearance variations over time, we relax the sparsity constraint using a weighed least squares (WLS) method to obtain the representation coefficients. To further reduce the computational complexity, structurally random projection is used to reduce the dimensionality of the feature space while preserving the pairwise distances between the data points in the feature space. Experimental results show that the proposed approach outperforms several state-of-the-art tracking methods.

Visual attention to food cues in obesity: An eye‐tracking study.

Objective
Based on the theory of incentive sensitization, the aim of this study was to investigate differences in attentional processing of food-related visual cues between normal-weight and overweight/obese males and females.

Methods
Twenty-six normal-weight (14M, 12F) and 26 overweight/obese (14M, 12F) adults completed a visual probe task and an eye-tracking paradigm. Reaction times and eye movements to food and control images were collected during both a fasted and fed condition in a counterbalanced design.

Results
Participants had greater visual attention towards high-energy-density food images compared to low-energy-density food images regardless of hunger condition. This was most pronounced in overweight/obese males who had significantly greater maintained attention towards high-energy-density food images when compared with their normal-weight counterparts however no between weight group differences were observed for female participants.

Conclusions
High-energy-density food images appear to capture visual attention more readily than low-energy-density food images. Results also suggest the possibility of an altered visual food cue-associated reward system in overweight/obese males. Attentional processing of food cues may play a role in eating behaviors thus should be taken into consideration as part of an integrated approach to curbing obesity.

Attentional bias to food-related visual cues: is there a role in obesity?

The incentive sensitisation model of obesity suggests that modification of the dopaminergic associated reward systems in the brain may result in increased awareness of food-related visual cues present in the current food environment. Having a heightened awareness of these visual food cues may impact on food choices and eating behaviours with those being most aware of or demonstrating greater attention to food-related stimuli potentially being at greater risk of overeating and subsequent weight gain. To date, research related to attentional responses to visual food cues has been both limited and conflicting. Such inconsistent findings may in part be explained by the use of different methodological approaches to measure attentional bias and the impact of other factors such as hunger levels, energy density of visual food cues and individual eating style traits that may influence visual attention to food-related cues outside of weight status alone. This review examines the various methodologies employed to measure attentional bias with a particular focus on the role that attentional processing of food-related visual cues may have in obesity. Based on the findings of this review, it appears that it may be too early to clarify the role visual attention to food-related cues may have in obesity. Results however highlight the importance of considering the most appropriate methodology to use when measuring attentional bias and the characteristics of the study populations targeted while interpreting results to date and in designing future studies.

Post-Conflict Performance, Film and Visual Arts:Cities of Memory

This book examines how contemporary theatre, performance, film and the visual arts respond to the post-conflict condition. The contents of the volume focus on a range of post-conflict cities, encouraging interdisciplinary discussion on the role of the arts and its relation to issues of testimony, witnessing, forgetting, representation, healing, reconciliation, agency, and metaphor. Contributors include: Thomas Elsaesser, Jane Taylor, Marvin Carlson, Rob Stone, Laurel Borisenko, Katarzyna Puzon, Miriam Paeslack, Emma Grey, Paula Blair, Zoran Poposki, Marija Todorova, Elena Carduro, and Paul Devlin.