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We examined the role of the right cerebral hemisphere in the recovery from aphasia of HJ, a 50-year-old right-handed and unilingual man who suffered from severe aphasia caused by an extensive left hemisphere (LH) lesion. He was followed-up over 10 months at 4-month intervals, with a lateralized lexical decision task (LDT), an attentional task, and a language battery. Testing started when HJ was 2 months poststroke. In the LDT, words were presented to central vision or lateralized to the left or right visual hemifield. At each test period, we examined the effect of the degree of imageability (high vs. low), and the grammatical class (noun vs. verb) of the targets on HJ's response times and error rates, with left visual field, right visual field, and central vision presentations. The results of the experiment showed that the pattern obtained with the LDT could not be accounted for by fluctuations in attention. There was an interaction of grammatical class with degree of imageability with left visual field displays only. The right hemisphere (RH) was faster with high-imageability words than with low-imageability words, regardless of their grammatical class. There was also an overall RH advantage on response times at 2 and 6 months after onset. This RH predominance coincided with a major recovery of language comprehension and the observation of semantic paralexias, while no major change in language expression was observed at that point. Ten months after onset, the pattern of lateralization changed, and response times for the LDT with either presentation site were equivalent. This LH improvement coincided with some recovery of language expression at the single-word level. The results of this study suggest that, in cases of severe aphasia caused by extensive LH lesions, the RH may play an important role in the recovery process. Furthermore, these results show that the contribution of the two cerebral hemispheres to recovery may vary overtime and affect specific aspects of language. [ABSTRACT FROM AUTHOR]

A series of three experiments was carried out in order to better characterize the representations that support long-term cognate priming. In Experiment 1, robust priming was obtained between orthographically similar French/English cognates in bilingual speakers, and this priming was mediated, in part, by orthographic codes, given that priming for these items was dramatically reduced following a study-test modality shift. In Experiment 2, no priming was obtained between the same set of French/English cognates in monolingual English speakers. Finally, in Experiment 3, priming for orthographically unrelated Arabic/French cognates was no larger than cross-modal priming, suggesting that these effects were mediated by nonorthographic representations. The role of orthography in supporting cognate priming is discussed. [ABSTRACT FROM AUTHOR]

Presents an abstract of the study 'Extent and Limits of Covert Lexical Activation in Letter-by-Letter Reading,' by M. Arguin, D. Bub and J. Bowers, which appeared in the 1998 issue of 'Cognitive Neuropsychology' journal.

Objective: This study identified metabolite modules associated with adiposity and body fat distribution in childhood using gold-standard measurements., Methods: We used cross-sectional data from 329 children at mid-childhood (age 5.3 ± 0.3 years; BMI 15.7 ± 1.5 kg/m 2 ) from the Genetics of Glucose regulation in Gestation and Growth (Gen3G), a prospective pre-birth cohort. We quantified 1038 plasma metabolites and measured body composition using the gold-standard dual-energy x-ray absorptiometry (DXA), in addition to skinfold, waist circumference, and BMI. We applied weighted-correlation network analysis to identify a network of highly correlated metabolite modules. Spearman's partial correlations were applied to determine the associations of adiposity with metabolite modules and individual metabolites with false discovery rate (FDR) correction., Results: We identified a 'green' module of 120 metabolites, primarily comprised of lipids (mostly sphingomyelins and phosphatidylcholine), that showed positive correlations (all FDR p < 0.05) with DXA estimates of total and truncal fat (ρ adjusted  = 0.11-0.19), skinfold measures (ρ adjusted  = 0.09-0.26), and BMI and waist circumference (ρ adjusted  = 0.15 and 0.18, respectively). These correlations were similar when stratified by sex. Within this module, sphingomyelin (d18:2/14:0, d18:1/14:1)*, a sphingomyelin sub-specie that is an important component of cell membranes, showed the strongest associations., Conclusions: A module of metabolites was associated with adiposity measures in childhood., (© 2024 World Obesity Federation.)

This study examined the temporal profile of spatial frequency processing in a word reading task in 16 normal adult readers. They had to report the word presented in a 200 ms display using a four-alternative forced-choice task (4AFC). The stimuli were made of an additive combination of the signal (i.e. the target word) and of a visual white noise patch wherein the signal-to-noise ratio varied randomly across stimulus duration. Four spatial frequency conditions were defined for the signal component of the stimulus (bandpass Butterworth filters with center frequencies of 1.2, 2.4, 4.8 and 9.6 cycles per degree). In contrast to the coarse-to-fine theory of visual recognition, the results show that the highest spatial frequency range dominates early processing, with a shift toward lower spatial frequencies at later points during stimulus exposure. This pattern interacted in a complex way with the temporal frequency content of signal-to-noise oscillations. The outcome of individual data patterns classification by a machine learning algorithm according to the corresponding spatial frequency band further shows that the most salient spatial frequency signature is obtained when the time dimension within data patterns is recoded into its Fourier transform., (© 2024. The Author(s).)

Background: Colorectal cancer (CRC) is a major cause of cancer mortality in the world. One of the most widely used screening tests for CRC is the immunochemical fecal occult blood test (iFOBT), which detects human hemoglobin from patient's stool sample. Although it is highly efficient in detecting blood from patients with gastro-intestinal lesions, such as polyps and cancers, the iFOBT has a high rate of false positive discovery. Recent studies suggested gut bacteria as a promising noninvasive biomarker for improving the diagnosis of CRC. In this study, we examined the composition of gut bacteria using iFOBT leftover from patients undergoing screening test along with a colonoscopy., Methods: After collecting data from more than 800 patients, we considered 4 groups for this study. The first and second groups were respectively "healthy" in which the patients had either no blood in their stool or had blood but no lesions. The third and fourth groups of patients had both blood in their stools with precancerous and cancerous lesions and considered either as low-grade and high-grade lesion groups, respectively. An amplification of 16S rRNA (V4 region) gene was performed, followed by sequencing along with various statistical and bioinformatic analysis., Results: We analyzed the composition of the gut bacteriome at phylum, class, genus, and species levels. Although members of the Firmicute phylum increased in the 3 groups compared to healthy patients, the phylum Actinobacteriota was found to decrease. Moreover, Blautia obeum and Anaerostipes hadrus from the phylum Firmicutes were increased and Collinsella aerofaciens from phylum Actinobacteriota was found decreased when healthy group is compared to the patients with high-grade lesions. Finally, among the 5 machine learning algorithms used to perform our analysis, both elastic net (AUC > 0.7) and random forest (AUC > 0.8) performs well in differentiating healthy patients from 3 other patient groups having blood in their stool., Conclusion: Our study integrates the iFOBT screening tool with gut bacterial composition to improve the prediction of CRC lesions., Competing Interests: Disclosure The authors have stated that they have no conflicts of interest., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The temporal features of visual processing were compared between young and elderly healthy participants in visual object and word recognition tasks using the technique of random temporal sampling. The target stimuli were additively combined with a white noise field and were exposed very briefly (200 ms). Target visibility oscillated randomly throughout exposure duration by manipulating the signal-to-noise ratio (SNR). Classification images (CIs) based on response accuracy were calculated to reflect processing efficiency according to the time elapsed since target onset and the power of SNR oscillations in the 5-55 Hz range. CIs differed substantially across groups whereas individuals of the same group largely shared crucial features such that a machine learning algorithm reached 100% accuracy in classifying the data patterns of individual participants into their proper group. These findings demonstrate altered perceptual oscillations in healthy aging and are consistent with previous investigations showing brain oscillation anomalies in the elderly., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lévesque and Arguin.)

Objective: To examine the associations between exposure to gestational diabetes mellitus (GDM) and maternal glycemic markers during pregnancy and offspring behaviors at 3 and 5 years. We hypothesized that exposure to maternal hyperglycemia would be associated with more behavioral problems in offspring., Methods: We included 548 mother-child pairs from the prospective pre-birth Gen3G cohort (Canada). Glycemic markers were measured during a 75 g oral glucose tolerance test (OGTT) in the second trimester of pregnancy. Based on OGTT, we classified 59 women (10.8%) as having GDM according to international diagnostic criteria. Mothers reported offspring behavior using the Strengths and Difficulties Questionnaire (SDQ) at 3 and 5 years, and the Child Behavior Checklist (CBCL) at 5 years. We used linear mixed models and multivariate regression to assess the associations between GDM or glycemic markers and children's behavior, adjusted for child sex and age, and maternal demographic factors, body mass index and family history of diabetes., Results: Exposure to GDM was associated with higher SDQ externalizing scores at 3 and 5 years [B = 1.12, 95% CI (0.14, 2.10)] in fully adjusted linear mixed models. These results were supported by the CBCL at 5 years. Higher levels of maternal glucose at 1 h and 2 h during OGTT were associated with greater SDQ externalizing scores. Fasting glucose levels were not associated with child behavior scores. We did not observe associations between glycemic markers and internalizing behaviors., Conclusions: Exposure to higher levels of maternal glycemia during pregnancy was associated with more externalizing behaviors in children at 3 and 5 years., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The contribution of stereopsis in human visual shape perception was examined using stimuli with either null, normal, or reversed binocular disparity in an old/new object recognition task. The highest levels of recognition performance were observed with null and normal binocular disparity displays, which did not differ. However, reversed disparity led to significantly worse performance than either of the other display conditions. This indicates that stereopsis provides a continuous input to the mechanisms involved in shape perception., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Exposure to maternal hyperglycemia in utero has been associated with adverse metabolic outcomes in offspring. However, few studies have investigated the relationship between maternal hyperglycemia and offspring cortisol levels. We assessed associations of gestational diabetes mellitus (GDM) with cortisol biomarkers in two longitudinal prebirth cohorts: Project Viva included 928 mother-child pairs and Gen3G included 313 mother-child pairs. In Project Viva, GDM was diagnosed in N = 48 (5.2%) women using a two-step procedure (50 g glucose challenge test, if abnormal followed by 100 g oral glucose tolerance test [OGTT]), and in N = 29 (9.3%) women participating in Gen3G using one-step 75 g OGTT. In Project Viva, we measured cord blood glucocorticoids and child hair cortisol levels during mid-childhood (mean (SD) age: 7.8 (0.8) years) and early adolescence (mean (SD) age: 13.2 (0.9) years). In Gen3G, we measured hair cortisol at 5.4 (0.3) years. We used multivariable linear regression to examine associations of GDM with offspring cortisol, adjusting for child age and sex, maternal prepregnancy body mass index, education, and socioeconomic status. We additionally adjusted for child race/ethnicity in the cord blood analyses. In both Project Viva and Gen3G, we observed null associations of GDM and maternal glucose markers in pregnancy with cortisol biomarkers in cord blood at birth (β = 16.6 nmol/L, 95% CI -60.7, 94.0 in Project Viva) and in hair samples during childhood (β = -0.56 pg/mg, 95% CI -1.16, 0.04 in Project Viva; β = 0.09 pg/mg, 95% CI -0.38, 0.57 in Gen3G). Our findings do not support the hypothesis that maternal hyperglycemia is related to hypothalamic-pituitary-adrenal axis activity.

Background: Childhood obesity has been associated with prenatal exposure to maternal hyperglycaemia, but we lack understanding about maternal insulin physiologic components that contribute to this association., Objectives: Evaluate the association between maternal insulin sensitivity during pregnancy and adiposity measures in childhood., Methods: In 422 mother-child pairs, we tested associations between maternal insulin sensitivity measures at ~26 weeks of pregnancy and child adiposity measures, including dual-energy X-ray absorptiometry body composition and anthropometry (body mass index and waist circumference) at ~5 years. We used linear regression analyses to adjust for maternal age, ethnicity, gravidity, first-trimester body mass index, and child sex and age at mid-childhood., Results: In early pregnancy, maternal mean age was 28.6 ± 4.3 years and median body mass index was 24.1 kg/m 2 . Lower maternal insulin sensitivity indices were correlated with greater child adiposity based on anthropometry measures and on dual-energy X-ray absorptiometry total and trunk % fat in univariate associations (r = -0.122 to -0.159). Lower maternal insulin sensitivity was specifically associated with higher dual-energy X-ray absorptiometry trunk % fat (n = 359 for Matsuda; β = -0.034 ± 0.013; p = 0.01) after adjustment for covariates, including maternal body mass index., Conclusions: Maternal insulin sensitivity during pregnancy may contribute to increased risk for higher offspring central adiposity in middle childhood., (© 2022 World Obesity Federation.)

Lower cord blood leptin levels have been associated with lower and higher adiposity in childhood and associations seem to differ according to the child’s age, methods of adiposity assessment and sex. Our aim was to investigate sex-specific associations of cord blood leptinemia with childhood adiposity at birth, 3 and 5 years of age. We measured cord blood leptin using Luminex immunoassays in 520 offspring from the Gen3G cohort. We tested associations between cord blood leptin and body mass index (BMI) z-score, skinfolds thicknesses (SFT), and body composition using dual-energy X-ray absorptiometry, adjusted for confounders. At birth, girls had almost twice as much leptin in cord blood as boys (15.5 [8.9; 25.6] vs. 8.6 [4.9; 15.0] ng/mL; p < 0.0001) as well as significantly greater adiposity. Lower levels of cord blood leptin were associated with higher sum of SFT (β = −0.05 ± 0.02; p = 0.03) and higher BMI z-score (β= −0.22 ± 0.08; p = 0.01) in 3-year-old boys only. We did not observe these associations at age 5, or in girls. Our results suggest a sexual dimorphism in the programming of leptin sensitivity and childhood adiposity, but further observational and functional studies are needed to better understand the role of leptin in early life.

It is increasingly apparent that functionally significant neural activity is oscillatory in nature. Demonstrating the implications of this mode of operation for perceptual/cognitive function remains somewhat elusive. This report describes the technique of random temporal sampling for the investigation of visual oscillatory mechanisms. The technique is applied in visual recognition experiments using different stimulus classes (words, familiar objects, novel objects, and faces). Classification images reveal variations of perceptual effectiveness according to the temporal features of stimulus visibility. These classification images are also decomposed into their power and phase spectra. Stimulus classes lead to distinct outcomes and the power spectra of classification images are highly generalizable across individuals. Moreover, stimulus class can be reliably decoded from the power spectrum of individual classification images. These findings and other aspects of the results validate random temporal sampling as a promising new method to study oscillatory visual mechanisms., (© 2021. The Author(s).)

Background: Maternal insulin resistance is associated with greater maternal inflammation during pregnancy, but its relation to inflammation in offspring remains unclear. The goal of this study was to assess the relationship of gestational insulin resistance and other glycemic markers with offspring inflammation at birth and at 5 years of age., Methods: We included 653 mother-child pairs from the prospective pre-birth Gen3G cohort. We examined maternal insulin and glucose levels measured during the second trimester of pregnancy, from which we derived the homeostatic model of assessment of insulin resistance (HOMA-IR) and the Matsuda index. We assessed offspring inflammation at birth and at 5 years of age by measuring plasma tumor necrosis factor-α (TNFα) concentrations. We conducted multivariable regression models to evaluate associations of each insulin and glucose marker with offspring inflammation adjusting for confounding variables., Results: Higher levels of fasting insulin were associated with lower TNFα levels at birth (-0.78, 95% CI [-1.45, -0.11]), in the fully adjusted model. We observed similar associations with the HOMA-IR and opposite direction with the Matsuda index. We did not find persistence of the association between maternal fasting insulin and offspring TNFα at 5 years of age., Conclusions: Greater maternal insulin resistance during pregnancy was associated with lower cord blood TNFα levels in newborns. The mechanisms by which maternal insulin resistance may promote lower inflammatory levels in newborns are not fully understood and more research is needed to deepen our understanding of these mechanisms., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Exposure to maternal hyperglycaemia in pregnancy has been associated with childhood obesity. Leptin regulation might be involved in this 'adiposity programming' and may depend on timing of exposure., Objectives: To investigate associations of maternal glycaemia at different periods in pregnancy with childhood adiposity and leptin levels at 5 years of age., Methods: In a prospective pre-birth cohort, we measured maternal glucose levels after a 50 g oral glucose challenge test at first trimester (9.8 ± 2.3 weeks) and during a 75 g oral glucose tolerance test at second trimester (26.5 ± 0.9 weeks). We followed up children at 5 years; we measured anthropometry and body composition using dual-energy X-ray absorptiometry (DXA). We measured fasting leptin levels using immunoassays (Luminex) in 328 children. We conducted linear regression analyses, adjusting for potential confounders., Results: Maternal glycaemia at first trimester was associated with childhood leptin levels at 5 years, independently of maternal pre-pregnancy BMI and other confounders (β = .09 ± .04; P = .03). Higher post-load glucose levels at second trimester were associated with greater total body fat percentage measured by DXA (1 hour-glucose: β = .010 ± .004; P = .03 and 2 hours-glucose: β = .016 ± .005; P = .002), but not with leptin levels., Conclusions: Our results suggest that programming of leptin regulation may be sensitive to maternal hyperglycaemia specifically in early pregnancy., (© 2021 World Obesity Federation.)

Background: Fetal exposure to maternal excess adiposity and hyperglycemia is risk factors for childhood adverse metabolic outcomes. Using data from a prospective pre-birth cohort, we aimed to further understand the prenatal determinants of fetal metabolic programming based on analyses of maternal adiposity and glycemic traits across pregnancy with childhood metabolomic profiles., Methods: This study included 330 mother-child pairs from the Gen3G cohort with information on maternal adiposity and glycemic markers at 5-16 (visit 1) and 24-30 (visit 2) weeks of pregnancy. At mid-childhood (4.8-7.2 years old), we collected fasting plasma and measured 1116 metabolites using an untargeted approach. We constructed networks of interconnected metabolites using a weighted-correlation network analysis algorithm. We estimated Spearman's partial correlation coefficients of maternal adiposity and glycemic traits across pregnancy with metabolite networks and individual metabolites, adjusting for maternal age, gravidity, race/ethnicity, history of smoking, and child's sex and age at blood collection for metabolite measurement., Results: We identified a network of 16 metabolites, primarily glycero-3-phosphoethanolamines (GPE) at mid-childhood that showed consistent negative correlations with maternal body mass index, waist circumference, and body-fat percentage at visits 1 and 2 (ρ adjusted  = -0.14 to -0.21) and post-challenge glucose levels at visit 2 (ρ adjusted  = -0.10 to -0.13), while positive correlations with Matsuda index (ρ adjusted  = 0.13). Within this identified network, 1-palmitoyl-2-decosahexaenoyl-GPE and 1-stearoyl-2-decosahexaenoyl-GPE appeared to be driving the associations. In addition, a network of 89 metabolites, primarily phosphatidylcholines, plasmalogens, sphingomyelins, and ceramides showed consistent negative correlations with insulin at visit 1 and post-challenge glucose at visit 2, while positive correlation with adiponectin at visit 2., Conclusions: Prenatal exposure to maternal higher adiposity and hyperglycemic traits and lower insulin sensitivity markers were associated with a unique metabolomic pattern characterized by low serum phospho- and sphingolipids in mid-childhood.

Cognistat is a cognitive screening test that is widely used in English-speaking countries. Its French adaptation is now available. The present study aims to establish norms for a population aged 60 and over. One hundred and fifty-one participants aged between 60 and 84 years old with normal cognitive function were divided into 5 five-year age groups. The results on Cognistat are reported for each subtest and age group. Age has a significant effect in only two subtests (Attention and Language Comprehension), which suggests a reduced performance for older participants. However, these effects are very weak and irregular. For this reason and given data distribution, norms are proposed to define performance thresholds for the 15th (lower limit of the normal range), 10th (mild cognitive impairment) and 5th (clinically significant) percentiles for each subtest for the clinical use of Cognistat with individuals 60 years of age and older.

One of two memory systems can be used to navigate in a new environment. Hippocampus-dependent spatial strategy consists of creating a cognitive map of an environment and caudate nucleus-dependent response strategy consists of memorizing a rigid sequence of turns. Spontaneous use of the response strategy is associated with greater activity and grey matter within the caudate nucleus while the spatial strategy is associated with greater activity and grey matter in the hippocampus. The caudate nucleus is involved in executive functions such as working memory, cognitive control and certain aspects of attention such as attentional disengaging. This study therefore aimed to investigate whether response learners would display better performance on tests of executive and attention functioning compared to spatial learners. Fifty participants completed the 4/8 virtual maze to assess navigational strategy, the forward and backward visual digit span and the Attention Network Test - Revised to assess both attention disengagement and cognitive control. Results revealed that response learners showed significantly higher working memory capacity, more efficient attention disengagement and better cognitive control. Results suggest that response learners, who putatively display more grey matter and activity in the caudate nucleus, are associated with better working memory span, cognitive control and attentional disengagement., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Considerable uncertainty remains regarding the types of features human vision uses for shape representation. Visual-search experiments are reported which assessed the hypothesis of a surface-based (i.e., edge-bounded polygons) code for shape representation in human vision. The results indicate slower search rates and/or longer response times when the target shape shares its constituent surfaces with distractors (conjunction condition) than when the target surfaces are unique in the display (nonconjunction condition). This demonstration is made using test conditions that strictly control any potential artifact pertaining to target-distractor similarity. The surface-based code suggested by this surface-conjunction effect is strictly 2-D, since the effect occurs even when the surfaces are shared between the target and distractors in the 2-D image but not in their 3-D instantiation. Congruently, this latter finding is unaltered by manipulations of the richness of the depth information offered by the stimuli. It is proposed that human vision uses a 2-D surface-based code for shape representation which, considering other key findings in the field, probably coexists with an alternative representation mode based on a type of structural description that can integrate information pertaining to the 3-D aspect of shapes.

De novo germline mutations arise preferentially in male owing to fundamental differences between spermatogenesis and oogenesis. Post-meiotic chromatin remodeling in spermatids results in the elimination of most of the nucleosomal supercoiling and is characterized by transient DNA fragmentation. Using three alternative methods, DNA from sorted populations of mouse spermatids was used to confirm that double-strand breaks (DSB) are created in elongating spermatids and repaired at later steps. Specific capture of DSB was used for whole-genome mapping of DSB hotspots (breakome) for each population of differentiating spermatids. Hotspots are observed preferentially within introns and repeated sequences hence are more prevalent in the Y chromosome. When hotspots arise within genes, those involved in neurodevelopmental pathways become preferentially targeted reaching a high level of significance. Given the non-templated DNA repair in haploid spermatids, transient DSBs formation may, therefore, represent an important component of the male mutation bias and the etiology of neurological disorders, adding to the genetic variation provided by meiosis.

DNA double-strand breaks (DSBs) represent a major threat to the genetic integrity of the cell. Knowing both their genome-wide distribution and number is important for a better assessment of genotoxicity at a molecular level. Available methods may have underestimated the extent of DSBs as they are based on markers specific to those undergoing active repair or may not be adapted for the large diversity of naturally occurring DNA ends. We have established conditions for an efficient first step of DNA nick and gap repair (NGR) allowing specific determination of DSBs by end labeling with terminal transferase. We used DNA extracted from HeLa cells harboring an I-SceI cassette to induce a targeted nick or DSB and demonstrated by immunocapture of 3'-OH that a prior step of NGR allows specific determination of loci-specific or genome wide DSBs. This method can be applied to the global determination of DSBs using radioactive end labeling and can find several applications aimed at understanding the distribution and kinetics of DSBs formation and repair., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Visuospatial attention can be deployed to different locations in space independently of ocular fixation, and studies have shown that event-related potential (ERP) components can effectively index whether such covert visuospatial attention is deployed to the left or right visual field. However, it is not clear whether we may obtain a more precise spatial localization of the focus of attention based on the EEG signals during central fixation. In this study, we used a modified Posner cueing task with an endogenous cue to determine the degree to which information in the EEG signal can be used to track visual spatial attention in presentation sequences lasting 200 ms. We used a machine learning classification method to evaluate how well EEG signals discriminate between four different locations of the focus of attention. We then used a multi-class support vector machine (SVM) and a leave-one-out cross-validation framework to evaluate the decoding accuracy (DA). We found that ERP-based features from occipital and parietal regions showed a statistically significant valid prediction of the location of the focus of visuospatial attention (DA = 57%, p < .001, chance-level 25%). The mean distance between the predicted and the true focus of attention was 0.62 letter positions, which represented a mean error of 0.55 degrees of visual angle. In addition, ERP responses also successfully predicted whether spatial attention was allocated or not to a given location with an accuracy of 79% (p < .001). These findings are discussed in terms of their implications for visuospatial attention decoding and future paths for research are proposed.

The differentiation of mouse spermatids is one critical process for the production of a functional male gamete with an intact genome to be transmitted to the next generation. So far, molecular studies of this morphological transition have been hampered by the lack of a method allowing adequate separation of these important steps of spermatid differentiation for subsequent analyses. Earlier attempts at proper gating of these cells using flow cytometry may have been difficult because of a peculiar increase in DNA fluorescence in spermatids undergoing chromatin remodeling. Based on this observation, we provide details of a simple flow cytometry scheme, allowing reproducible purification of four populations of mouse spermatids fixed with ethanol, each representing a different state in the nuclear remodeling process. Population enrichment is confirmed using step-specific markers and morphological criterions. The purified spermatids can be used for genomic and proteomic analyses.

Transient DNA breaks and evidence of DNA damage response have recently been reported during the chromatin remodeling process in haploid spermatids, creating a potential window of enhanced genetic instability. We used flow cytometry to achieve separation of differentiating spermatids into four highly purified populations using transgenic mice harboring 160 CAG repeats within exon 1 of the human Huntington disease gene (HTT). Trinucleotic repeat expansion was found to occur immediately following the chromatin remodeling steps, confirming the genetic instability of the process and pointing to the origin of paternal anticipation observed in some trinucleotidic repeats diseases., (© 2014 WILEY PERIODICALS, INC.)

The present study investigated the joint impact of target-flanker similarity and of spatial frequency content on the crowding effect in letter identification. We presented spatial frequency filtered letters to neurologically intact non-dyslexic readers while manipulating target-flanker distance, target eccentricity and target-flanker confusability (letter similarity metric based on published letter confusion matrices). The results show that high target-flanker confusability magnifies crowding. They also reveal an intricate pattern of interactions of the spatial frequency content of the stimuli with target eccentricity, flanker distance and similarity. The findings are congruent with the notion that crowding results from the inappropriate pooling of target and flanker features and that this integration is more likely to match a response template at a subsequent decision stage with similar than dissimilar flankers. In addition, the evidence suggests that crowding from similar flankers is biased towards relatively high spatial frequencies and that crowding shifts towards lower spatial frequencies as target eccentricity is increased., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The present study examined the joint contribution of shading and stereopsis to the perception of shape convexity-concavity. The stimuli were the images of a synthetic convex 3-D shape seen from viewpoints leading to ambiguity as to its convexity. Illumination came from either above or below, and from either the right or the left, and stimuli were presented dichoptically with normal binocular disparity, reversed disparity, or no disparity. Participants responded "convex" more often when the lighting came from above than from below. Also, participants responded that the shape was convex more often with normal than with zero disparity, and more often with zero disparity than with reversed stereopsis. The effects of lighting direction and display mode were additive--that is, they did not interact. This indicates that shading and stereopsis contribute independently to shape perception.

During the haploid phase of spermatogenesis, spermatids undergo a complex remodeling of the paternal genome involving the finely orchestrated replacement of histones by the highly-basic protamines. The associated striking change in DNA topology is characterized by a transient surge of both single- and double-stranded DNA breaks in the whole population of spermatids which are repaired before spermiation. These transient DNA breaks are now considered part of the normal differentiation program of these cells. Despite an increasing interest in the study of spermiogenesis in the last decade and the potential threat to the haploid genome, the origin of these DNA breaks still remains elusive. This review briefly outlines the current hypotheses regarding possible mechanisms that may lead to such transient DNA fragmentation including torsional stress, enzyme-induced breaks, apoptosis-like processes or oxidative stress. A better understanding of the origin of these DNA breaks will lead to further investigations on the genetic instability and mutagenic potential induced by the chromatin remodeling.

In an effort to understand the factors influencing text legibility in natural reading, we adapted the visual spread method (Poirier, Gosselin, & Arguin, 2008) to natural text. Stimuli were sentences conforming to MNREAD standards (Legge, Ross, Luebker, & LaMay 1989) mixed with dynamic probabilistic noise-i.e., each pixel in the image is associated with a probability that its polarity is inverted on a given refresh cycle of the display screen. Noise level varied continuously over the image as initially determined by Gaussian-filtered noise. Participants adjusted noise levels in the text using the mouse until the text appeared homogenously noisy. We assume that participants increased (or decreased) noise at locations where stimulus features were easy (or difficult) to encode and thus that local noise settings correlate with legibility. Data from 11 participants and 30 sentences revealed interesting effects, demonstrating the validity of the method for assessing the impact of various factors on noise resistance in natural text. For example, participants increased noise over (a) spaces and adjacent letters, (b) the second half of words, (c) words with more orthographic neighbors but fewer phonological neighbors, (d) less useful word types, (e) less complex letters, and (f) diagnostic letters (a novel metric). Our observations also offer significant insights on constraints acting upon letter identification as well as on higher-level processes that are involved in reading.

Recent investigations have proposed that visual information may be sampled in a discrete manner, similarly to the snapshots of a camera, but this hypothesis remains controversial. Moreover, assuming a discrete sampling of information, the properties of this sampling-for instance, the frequency at which it operates, and how it synchronizes with the environment-still need to be clarified. We systematically modulated the signal-to-noise ratio of faces through time and examined how it impacted face identification performance. Altogether, our results support the hypothesis of discrete sampling. Furthermore, they suggest that this mechanism may operate at a rate of about 10-15Hz and that it is synchronized with the onset of the stimulus., (Copyright © 2013 Elsevier B.V. All rights reserved.)

At the sequence level, genetic diversity is provided by de novo transmittable mutations that may act as a substrate for natural selection. The gametogenesis process itself is considered more likely to induce endogenous mutations and a clear male bias has been demonstrated from recent next-generation sequencing analyses. As new experimental evidence accumulates, the post-meiotic events of the male gametogenesis (spermiogenesis) appear as an ideal context to induce de novo genetic polymorphism transmittable to the next generation. It may prove to be a major component of the observed male mutation bias. As spermatids undergo chromatin remodeling, transient endogenous DNA double-stranded breaks are produced and trigger a DNA damage response. In these haploid cells, one would expect that the non-templated, DNA end-joining repair processes may generate a repertoire of sequence alterations in every sperm cell potentially transmittable to the next generation. This may therefore represent a novel physiological mechanism contributing to genetic diversity and evolution.

It is generally accepted that the left hemisphere (LH) is more capable for reading than the right hemisphere (RH). Left hemifield presentations (initially processed by the RH) lead to a globally higher error rate, slower word identification, and a significantly stronger word length effect (i.e., slower reaction times for longer words). Because the visuo-perceptual mechanisms of the brain for word recognition are primarily localized in the LH (Cohen et al., 2003), it is possible that this part of the brain possesses better spatial frequency (SF) tuning for processing the visual properties of words than the RH. The main objective of this study is to determine the SF tuning functions of the LH and RH for word recognition. Each word image was randomly sampled in the SF domain using the SF bubbles method (Willenbockel et al., 2010) and was presented laterally to the left or right visual hemifield. As expected, the LH requires less visual information than the RH to reach the same level of performance, illustrating the well-known LH advantage for word recognition. Globally, the SF tuning of both hemispheres is similar. However, these seemingly identical tuning functions hide important differences. Most importantly, we argue that the RH requires higher SFs to identify longer words because of crowding.

Facial expressions are one of the most important ways to communicate our emotional state. In popular culture and in the scientific literature on face processing, the eye area is often conceived as a very important - if not the most important - cue for the recognition of facial expressions. In support of this, an underutilization of the eye area is often observed in clinical populations with a deficit in the recognition of facial expressions of emotions. Here, we used the Bubbles technique to verify which facial cue is the most important when it comes to discriminating between eight static and dynamic facial expressions (i.e., six basic emotions, pain and a neutral expression). We found that the mouth area is the most important cue for both static and dynamic facial expressions. We conducted an ideal observer analysis on the static expressions and determined that the mouth area is the most informative. However, we found an underutilization of the eye area by human participants in comparison to the ideal observer. We then demonstrated that the mouth area contains the most discriminative motions across expressions. We propose that the greater utilization of the mouth area by the human participants might come from remnants of the strategy the brain has developed with dynamic stimuli, and/or from a strategy whereby the most informative area is prioritized due to the limited capacity of the visuo-cognitive system., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Identical textured disks can appear white or black depending on the luminance properties of the surrounding textured region (B. L. Anderson & J. Winawer, 2005, 2008). This occurs when the stimulus is perceptually segmented in three layers: (1) a uniform foreground disk, (2) a uniform background surface, and (3) a cloud-like layer that covers parts of the foreground and background regions. However, local occlusion cues fail to predict the pattern of data observed, suggesting that in some cases a different strategy may be adopted depending on texture characteristics (F. J. A. M. Poirier, 2009). Here, we produced a variety of stimuli using three different textures and several luminance configurations (including the White and inverse White configurations and the Anderson-Winawer illusion), for which participants reported the perceived characteristics of the central disk (e.g., lightness, transparency, whether the disk was textured). The results show several interactions between textures and luminance configurations, which we account for using mathematical models of previously documented strategies. We show how the strategies chosen depend on an interaction between texture properties and luminance configuration.

The sustained posterior contralateral negativity (SPCN) was used to investigate the effect of spatial layout on the maintenance of letters in VSTM. SPCN amplitude was measured for words, nonwords, and scrambled nonwords. We reexamined the effects of spatial layout of letters on SPCN amplitude in a design that equated the mean frequency of use of each position. Scrambled letters that did not form words elicited a larger SPCN than either words or nonwords, indicating lower VSTM load for nonwords presented in a typical horizontal array than the load observed for the same letters presented in spatially scrambled locations. In contrast, prior research has shown that the spatial extent of arrays of simple stimuli did not influence the amplitude of the SPCN. Thus, the present results indicate the existence of encoding and VSTM maintenance mechanisms specific to letter and word processing., (Copyright © 2010 Society for Psychophysiological Research.)

Determination of cellular DNA damage has so far been limited to global assessment of genome integrity whereas nucleotide-level mapping has been restricted to specific loci by the use of specific primers. Therefore, only limited DNA sequences can be studied and novel regions of genomic instability can hardly be discovered. Using a well-characterized yeast model, we describe a straightforward strategy to map genome-wide DNA strand breaks without compromising nucleotide-level resolution. This technique, termed "damaged DNA immunoprecipitation" (dDIP), uses immunoprecipitation and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin end-labeling (TUNEL) to capture DNA at break sites. When used in combination with microarray or next-generation sequencing technologies, dDIP will allow researchers to map genome-wide DNA strand breaks as well as other types of DNA damage and to establish a clear profiling of altered genes and/or intergenic sequences in various experimental conditions. This mapping technique could find several applications for instance in the study of aging, genotoxic drug screening, cancer, meiosis, radiation and oxidative DNA damage.

The authors examined spatial frequency (SF) tuning of upright and inverted face identification using an SF variant of the Bubbles technique (F. Gosselin & P. G. Schyns, 2001). In Experiment 1, they validated the SF Bubbles technique in a plaid detection task. In Experiments 2a-c, the SFs used for identifying upright and inverted inner facial features were investigated. Although a clear inversion effect was present (mean accuracy was 24% higher and response times 455 ms shorter for upright faces), SF tunings were remarkably similar in both orientation conditions (mean r = .98; an SF band of 1.9 octaves centered at 9.8 cycles per face width for faces of about 6 degrees ). In Experiments 3a and b, the authors demonstrated that their technique is sensitive to both subtle bottom-up and top-down induced changes in SF tuning, suggesting that the null results of Experiments 2a-c are real. The most parsimonious explanation of the findings is provided by the quantitative account of the face inversion effect: The same information is used for identifying upright and inverted inner facial features, but processing has greater sensitivity with the former.

Background: Skilled adult readers, in contrast to beginners, show no or little increase in reading latencies as a function of the number of letters in words up to seven letters. The information extraction strategy underlying such efficiency in word identification is still largely unknown, and methods that allow tracking of the letter information extraction through time between eye saccades are needed to fully address this question., Methodology/principal Findings: The present study examined the use of letter information during reading, by means of the Bubbles technique. Ten participants each read 5,000 five-letter French words sampled in space-time within a 200 ms window. On the temporal dimension, our results show that two moments are especially important during the information extraction process. On the spatial dimension, we found a bias for the upper half of words. We also show for the first time that letter positions four, one, and three are particularly important for the identification of five-letter words., Conclusions/significance: Our findings are consistent with either a partially parallel reading strategy or an optimal serial reading strategy. We show using computer simulations that this serial reading strategy predicts an absence of a word-length effect for words from four- to seven letters in length. We believe that the Bubbles technique will play an important role in further examining the nature of reading between eye saccades.

Herein, we investigated the survival roles of Fak, Src, MEK/Erk, and PI3-K/Akt-1 in intestinal epithelial cancer cells (HCT116, HT29, and T84), in comparison to undifferentiated and differentiated intestinal epithelial cells (IECs). We report that: (1) cancer cells display striking anoikis resistance, as opposed to undifferentiated/differentiated IECs; (2) under anoikis conditions and consequent Fak down-activation, cancer cells nevertheless exhibit sustained Fak-Src interactions and Src/MEK/Erk activation, unlike undifferentiated/differentiated IECs; however, HCT116 and HT29 cells exhibit a PI3-K/Akt-1 down-activation, as undifferentiated/differentiated IECs, whereas T84 cells do not; (3) cancer cells require MEK/Erk for survival, as differentiated (but not undifferentiated) IECs; however, T84 cells do not require Fak and HCT116 cells do not require PI3-K/Akt-1, in contrast to the other cells studied; (4) Src acts as a cornerstone in Fak-mediated signaling to MEK/Erk and PI3-K/Akt-1 in T84 cells, as in undifferentiated IECs, whereas PI3-K/Akt-1 is Src-independent in HCT116, HT29 cells, as in differentiated IECs; and (5) EGFR activity inhibition abrogates anoikis resistance in cancer cells through a loss of Fak-Src interactions and down-activation of Src/MEK/Erk (T84, HCT116, HT29 cells) and PI3-K/Akt-1 (T84 cells). Hence, despite distinctions in signaling behavior not necessarily related to undifferentiated or differentiated IECs, intestinal epithelial cancer cells commonly display an EGFR-mediated sustained activation of Src under anoikis conditions. Furthermore, such sustained Src activation confers anoikis resistance at least in part through a consequent sustenance of Fak-Src interactions and MEK/Erk activation, thus not only overriding Fak-mediated signaling to MEK/Erk and/or PI3-K/Akt-1, but also the requirement of Fak and/or PI3-K/Akt-1 for survival., (2009 Wiley-Liss, Inc.)

The decomposition of three-dimensional (3-D) objects into shape primitives consisting of geometric volumes is a key proposal of some theories of object recognition. It implicitly assumes that recognition involves volumetric completion--the derivation of a three-dimensional structure that comprises inferred shape properties, such as surfaces, that are not directly visible due to self-occlusion. The goal of this study was to test this claim. In Experiment 1 participants memorized novel objects and then discriminated these from previously unseen objects. Targets were preceded by primes containing a subset of object surfaces that either matched those visible in the whole objects or that could only be inferred through volumetric completion. The results showed performance benefits through priming from visible surfaces but not from inferred surfaces. In Experiment 2, we found equivalent priming for part-primes containing two visible surfaces from the same volumetric part and for primes containing one surface from each of two volumes. These results challenge the view that 3-D object recognition is mediated by shape primitives comprising geometric volumes. Instead, the results support an alternative model that proposes that 3-D shapes are represented as a non-volumetric surface-based structural description.

Observers encoded the spatial arrangement of two or three horizontal line segments relative to a square frame presented for 150 ms either in left or right visual field and either above or below the horizontal midline. The target pattern was selected on the basis of colour (red vs. green) from an equivalent distractor pattern in the opposite left-right visual hemifield. After a retention interval of 450 or 650 ms a test pattern was presented at fixation. The task was to decide whether the test was the same as the encoded pattern or different. Selection of the to-be-memorized pattern produced an N2pc response that was not influenced by the number of line segments nor by the length of the retention interval, but that was smaller in amplitude for patterns presented in the upper visual field compared with patterns presented in the lower visual field. A sustained posterior contralateral negativity (SPCN) followed the N2pc. The SPCN was larger for patterns with three line segments than for two, was larger for patterns encoded from lower visual field than from upper visual field, and returned to baseline sooner for the shorter retention interval than for the longer interval. These results, and others, provide an interesting and complex pattern of similarities and differences between the N2pc and SPCN, consistent with the view that N2pc reflects mechanisms of attentional selection whereas the SPCN reflects maintenance in visual short-term memory.

Humans recognize basic facial expressions effortlessly. Yet, despite a considerable amount of research, this task remains elusive for computer vision systems. Here, we compared the behavior of one of the best computer models of facial expression recognition (Z. Hammal, L. Couvreur, A. Caplier, & M. Rombaut, 2007) with the behavior of human observers during the M. Smith, G. Cottrell, F. Gosselin, and P. G. Schyns (2005) facial expression recognition task performed on stimuli randomly sampled using Gaussian apertures. The model--which we had to significantly modify in order to give the ability to deal with partially occluded stimuli--classifies the six basic facial expressions (Happiness, Fear, Sadness, Surprise, Anger, and Disgust) plus Neutral from static images based on the permanent facial feature deformations and the Transferable Belief Model (TBM). Three simulations demonstrated the suitability of the TBM-based model to deal with partially occluded facial parts and revealed the differences between the facial information used by humans and by the model. This opens promising perspectives for the future development of the model.

To assess directly the orientation-invariance of specific shape representation stages in humans, we examined whether rotation (on the image plane or in depth) modulates the conjunction and linear non-separability effects in a shape visual search task (M. Arguin & D. Saumier, 2000; D. Saumier & M. Arguin, 2003). A series of visual search experiments involving simple 2D or 3D shapes show that these target type effects are entirely resistant to both planar and depth rotations. It was found however, that resistance to depth rotation only occurred when the 3D shapes had a richly textured surface but not when they had a uniform surface, with shading as the only reliable depth cue. The results also indicate that both planar and depth rotations affected performance indexes not concerned with the target type effects (i.e. overall RTs and magnitude of display size and target presence effects). Overall, the present findings suggest that the shape representations subtending the conjunction and linear non-separability effects are invariant across both planar and depth rotations whereas other shape representation stages involved in the task are orientation-specific.

We applied the Bubbles technique to reveal directly the spatio-temporal features of uppercase Arial letter identification. We asked four normal readers to each identify 26,000 letters that were randomly sampled in space and time; afterwards, we performed multiple linear regressions on the participant's response accuracy and the space-time samples. We contend that each cluster of connected significant regression coefficients is a letter feature. To bridge the gap between the letter identification literature and this experiment, we also determined the relative importance of the features proposed in the letter identification literature. Results show clear modulations of the relative importance of the letter features of some letters across time, demonstrating that letter features are not always extracted simultaneously at constant speeds. Furthermore, of all the feature classes proposed in the literature, line terminations and horizontals appear to be the two most important for letter identification.

Electrophysiological measures were used to investigate the contribution of lexical status on the maintenance of letter strings in visual short-term memory (VSTM). The sustained posterior contralateral negativity (SPCN), an electrophysiological marker of storage in VSTM, was measured for words and nonwords as well as scrambled letters. A smaller SPCN was found for words than for nonwords (independently of their pronounceability), indicating that lexical status influences storage in VSTM. One possibility is that words produce a smaller SPCN because they can be recoded to a form that does not require a low-level representation in VSTM. For exploratory purpose, a comparison between the nonwords and the scrambled nonwords was also made. Based on previous research, the SPCN component should not be affected by the size of the region enclosing to-be-encoded objects. Surprisingly, significant differences between the SPCN for nonwords and scrambled letters conditions were found, suggesting that special encoding mechanisms may be recruited to encode word-like letter strings.