Prefrontal abnormalities, executive dysfunction and symptoms severity are modulated by COMT Val158Met polymorphism in first episode psychosis

INTRODUCTION

Core dysfunctions proposed for psychotic disorders include prefrontal cortex (PFC) dopaminergic hypoactivity, executive function (EF) deficits and reduced gray matter in the PFC. The Val variant of COMT Val₁₅₈Met polymorphism is associated with reduced dopaminergic signaling in the PFC. However, it is unclear how COMT Val₁₅₈Met modulates PFC gray matter reduction, EF deficits and symptom severity at the time of the first psychotic episode.

METHODS

The effect of COMT on both EF performance and prefrontal volume (PFC-VOL) was tested in 158 first episode psychosis (FEP) patients and 141 healthy controls (HC) matched for age (range 9-35 years), sex, ethnicity, handedness and COMT Val₁₅₈Met distribution. EF and PFC-VOL were compared between FEP and HC groups within each polymorphism status (Met/Met versus Val carriers) to assess whether COMT influenced diagnostic differences. Next, correlations between PFC-VOL and EF performance were computed, as well as between both variables and other clinical characteristics of interest (PANSS scores, PAS infancy and premorbid IQ) in the FEP sample.

RESULTS

COMT influenced the diagnostic differences mainly in PFC-VOL, but also in EF performance. FEP-Val carriers showed lower EF scores and reduced PFC-VOL compared to the HC group but also poorer EF performance than FEP Met/Met. Poorer EF performance was associated with smaller PFC-VOL, and both were related to increased severity of negative symptoms, poorer premorbid adjustment, and lower estimated premorbid IQ in FEP patients.

CONCLUSIONS

Our findings suggest that COMT Val₁₅₈Met polymorphism might contribute to PFC-VOL reductions, executive dysfunctions and symptom severity in FEP patients.

Effects of copy number variations on brain structure and risk for psychiatric illness: Large-scale studies from the ENIGMA working groups on CNVs

The Enhancing NeuroImaging Genetics through Meta-Analysis copy number variant (ENIGMA-CNV) and 22q11.2 Deletion Syndrome Working Groups (22q-ENIGMA WGs) were created to gain insight into the involvement of genetic factors in human brain development and related cognitive, psychiatric and behavioral manifestations. To that end, the ENIGMA-CNV WG has collated CNV and magnetic resonance imaging (MRI) data from ~49,000 individuals across 38 global research sites, yielding one of the largest studies to date on the effects of CNVs on brain structures in the general population. The 22q-ENIGMA WG includes 12 international research centers that assessed over 533 individuals with a confirmed 22q11.2 deletion syndrome, 40 with 22q11.2 duplications, and 333 typically developing controls, creating the largest-ever 22q11.2 CNV neuroimaging data set. In this review, we outline the ENIGMA infrastructure and procedures for multi-site analysis of CNVs and MRI data. So far, ENIGMA has identified effects of the 22q11.2, 16p11.2 distal, 15q11.2, and 1q21.1 distal CNVs on subcortical and cortical brain structures. Each CNV is associated with differences in cognitive, neurodevelopmental and neuropsychiatric traits, with characteristic patterns of brain structural abnormalities. Evidence of gene-dosage effects on distinct brain regions also emerged, providing further insight into genotype-phenotype relationships. Taken together, these results offer a more comprehensive picture of molecular mechanisms involved in typical and atypical brain development. This "genotype-first" approach also contributes to our understanding of the etiopathogenesis of brain disorders. Finally, we outline future directions to better understand effects of CNVs on brain structure and behavior.

Altered white matter microstructure in 22q11.2 deletion syndrome: a multisite diffusion tensor imaging study

22q11.2 deletion syndrome (22q11DS)-a neurodevelopmental condition caused by a hemizygous deletion on chromosome 22-is associated with an elevated risk of psychosis and other developmental brain disorders. Prior single-site diffusion magnetic resonance imaging (dMRI) studies have reported altered white matter (WM) microstructure in 22q11DS, but small samples and variable methods have led to contradictory results. Here we present the largest study ever conducted of dMRI-derived measures of WM microstructure in 22q11DS (334 22q11.2 deletion carriers and 260 healthy age- and sex-matched controls; age range 6-52 years). Using harmonization protocols developed by the ENIGMA-DTI working group, we identified widespread reductions in mean, axial and radial diffusivities in 22q11DS, most pronounced in regions with major cortico-cortical and cortico-thalamic fibers: the corona radiata, corpus callosum, superior longitudinal fasciculus, posterior thalamic radiations, and sagittal stratum (Cohen's d's ranging from -0.9 to -1.3). Only the posterior limb of the internal capsule (IC), comprised primarily of corticofugal fibers, showed higher axial diffusivity in 22q11DS. 22q11DS patients showed higher mean fractional anisotropy (FA) in callosal and projection fibers (IC and corona radiata) relative to controls, but lower FA than controls in regions with predominantly association fibers. Psychotic illness in 22q11DS was associated with more substantial diffusivity reductions in multiple regions. Overall, these findings indicate large effects of the 22q11.2 deletion on WM microstructure, especially in major cortico-cortical connections. Taken together with findings from animal models, this pattern of abnormalities may reflect disrupted neurogenesis of projection neurons in outer cortical layers.

Sensory-to-Cognitive Systems Integration Is Associated With Clinical Severity in Autism Spectrum Disorder

OBJECTIVE

Impaired multisensory integration in autism spectrum disorder (ASD) may arise from functional dysconnectivity among brain systems. Our study examines the functional connectivity integration between primary modal sensory regions and heteromodal processing cortex in ASD, and whether abnormalities in network integration relate to clinical severity.

METHOD

We studied a sample of 55 high-functioning ASD and 64 healthy control (HC) male children and adolescents (total n = 119, age range 7-18 years). Stepwise functional connectivity analysis (SFC) was applied to resting state functional magnetic resonance images (rsfMRI) to characterize the connectivity paths that link primary sensory cortices to higher-order brain cognitive functional circuits and to relate alterations in functional connectivity integration with three clinical scales: Social Communication Questionnaire, Social Responsiveness Scale, and Vineland Adaptive Behavior Scales.

RESULTS

HC displayed typical functional connectivity transitions from primary sensory systems to association areas, but the ASD group showed altered patterns of multimodal sensory integration to heteromodal systems. Specifically, compared to the HC group, the ASD group showed the following: (1) hyperconnectivity in the visual cortex at initial link step distances; (2) hyperconnectivity between sensory unimodal regions and regions of the default mode network; and (3) hypoconnectivity between sensory unimodal regions and areas of the fronto-parietal and attentional networks. These patterns of hyper- and hypoconnectivity were associated with increased clinical severity in ASD.

CONCLUSION

Networkwise reorganization in high-functioning ASD individuals affects strategic regions of unimodal-to-heteromodal cortical integration predicting clinical severity. In addition, SFC analysis appears to be a promising approach for studying the neural pathophysiology of multisensory integration deficits in ASD.

Cortical surface area variations within the dorsolateral prefrontal cortex are better predictors of future cognitive performance than fluid ability and working memory

BACKGROUND

Are cognitive and biological variables useful for predicting future behavioral outcomes?

METHOD

In two independent groups, we measured a set of cognitive (fluid and crystallized intelligence, working memory, and attention control) and biological (cortical thickness and cortical surface area) variables on two occasions separated by six months, to predict behavioral outcomes of interest (performance on an adaptive version of the n-back task) measured twelve and eighteen months later. We followed three stages: discovery, validation, and generalization. In the discovery stage, cognitive/biological variables and the behavioral outcome of interest were assessed in a group of individuals (in-sample). In the validation stage, the cognitive and biological variables were related with a parallel version of the behavioral outcome assessed several months later. In the generalization stage, the validation findings were tested in an independent group of individuals (out-of-sample).

RESULTS

The key finding revealed that cortical surface area variations within the right dorsolateral prefrontal cortex predict the behavioral outcome of interest in both groups, whereas the cognitive variables failed to show reliable predictive validity.

CONCLUSIONS

Individual differences in biological variables might predict future behavioral outcomes better than cognitive variables concurrently correlated with these behavioral outcomes.

Neuroanatomical deficits shared by youth with autism spectrum disorders and psychotic disorders

Autism spectrum disorders (ASD) and early-onset psychosis (EOP) are neurodevelopmental disorders that share genetic, clinical and cognitive facets; it is unclear if these disorders also share spatially overlapping cortical thickness (CT) and surface area (SA) abnormalities. MRI scans of 30 ASD, 29 patients with early-onset first-episode psychosis (EO-FEP) and 26 typically developing controls (TD) (age range 10-18 years) were analyzed by the FreeSurfer suite to calculate vertex-wise estimates of CT, SA, and cortical volume. Two publicly available datasets of ASD and EOP (age range 7-18 years and 5-17 years, respectively) were used for replication analysis. ASD and EO-FEP had spatially overlapping areas of cortical thinning and reduced SA in the bilateral insula (all p's < .00002); 37% of all left insular vertices presenting with significant cortical thinning and 20% (left insula) and 61% (right insula) of insular vertices displaying decreased SA overlapped across both disorders. In both disorders, SA deficits contributed more to cortical volume decreases than reductions in CT did. This finding, as well as the novel finding of an absence of spatial overlap (for ASD) or marginal overlap (for EOP) of deficits in CT and SA, was replicated in the two nonoverlapping independent samples. The insula appears to be a region with transdiagnostic vulnerability for deficits in CT and SA. The finding of nonexistent or small spatial overlap between CT and SA deficits in young people with ASD and psychosis may point to the involvement of common aberrant early neurodevelopmental mechanisms in their pathophysiology.

Local functional connectivity suggests functional immaturity in children with attention-deficit/hyperactivity disorder

Previous studies have associated Attention-Deficit/Hyperactivity Disorder (ADHD) with a maturational lag of brain functional networks. Functional connectivity of the human brain changes from primarily local to more distant connectivity patterns during typical development. Under the maturational lag hypothesis, we expect children with ADHD to exhibit increased local connectivity and decreased distant connectivity compared with neurotypically developing (ND) children. We applied a graph-theory method to compute local and distant connectivity levels and cross-sectionally compared them in a sample of 120 children with ADHD and 120 age-matched ND children (age range = 7-17 years). In addition, we measured if potential group differences in local and distant connectivity were stable across the age range considered. Finally, we assessed the clinical relevance of observed group differences by correlating the connectivity levels and ADHD symptoms severity separately for each group. Children with ADHD exhibited more local connectivity than age-matched ND children in multiple brain regions, mainly overlapping with default mode, fronto-parietal and ventral attentional functional networks (p < .05- threshold free-cluster enhancement-family-wise error). We detected an atypical developmental pattern of local connectivity in somatomotor regions, that is, decreases with age in ND children, and increases with age in children with ADHD. Furthermore, local connectivity within somatomotor areas correlated positively with clinical severity of ADHD symptoms, both in ADHD and ND children. Results suggest an immature functional state of multiple brain networks in children with ADHD. Whereas the ADHD diagnosis is associated with the integrity of the system comprising the fronto-parietal, default mode and ventral attentional networks, the severity of clinical symptoms is related to atypical functional connectivity within somatomotor areas. Additionally, our findings are in line with the view of ADHD as a disorder of deviated maturational trajectories, mainly affecting somatomotor areas, rather than delays that normalize with age.

The association between gene variants and longitudinal structural brain changes in psychosis: a systematic review of longitudinal neuroimaging genetics studies

Evidence suggests that genetic variation might influence structural brain alterations in psychotic disorders. Longitudinal genetic neuroimaging (G-NI) studies are designed to assess the association between genetic variants, disease progression and brain changes. There is a paucity of reviews of longitudinal G-NI studies in psychotic disorders. A systematic search of PubMed from inception until November 2016 was conducted to identify longitudinal G-NI studies examining the link between Magnetic Resonance Imaging (MRI) and Diffusion Tensor Imaging (DTI)-based brain measurements and specific gene variants (SNPs, microsatellites, haplotypes) in patients with psychosis. Eleven studies examined seven genes: BDNF, COMT, NRG1, DISC1, CNR1, GAD1, and G72. Eight of these studies reported at least one association between a specific gene variant and longitudinal structural brain changes. Genetic variants associated with longitudinal brain volume or cortical thickness loss included a 4-marker haplotype in G72, a microsatellite and a SNP in NRG1, and individual SNPs in DISC1, CNR1, BDNF, COMT and GAD1. Associations between genotype and progressive brain changes were most frequently observed in frontal regions, with five studies reporting significant interactions. Effect sizes for significant associations were generally of small or intermediate magnitude (Cohen’s d < 0.8). Only two genes (BDNF and NRG1) were assessed in more than one study, with great heterogeneity of the results. Replication studies and studies exploring additional genetic variants identified by large-scale genetic analysis are warranted to further ascertain the role of genetic variants in longitudinal brain changes in psychosis.

Atypical age-dependency of executive function and white matter microstructure in children and adolescents with autism spectrum disorders

Executive function (EF) performance is associated with measurements of white matter microstructure (WMS) in typical individuals. Impaired EF is a hallmark symptom of autism spectrum disorders (ASD) but it is unclear how impaired EF relates to variability in WMS. Twenty-one male youth (8-18 years) with ASD and without intellectual disability and twenty-one typical male participants (TP) matched for age, intelligence quotient, handedness, race and parental socioeconomic status were recruited. Five EF domains were assessed and several DTI-based measurements of WMS [fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD)] were estimated for eighteen white matter tracts. The ASD group had lower scores for attention (F = 8.37, p = 0.006) and response inhibition (F = 13.09, p = 0.001). Age-dependent changes of EF performance and WMS measurements were present in TP but attenuated in the ASD group. The strongest diagnosis-by-age effect was found for forceps minor, left anterior thalamic radiation and left cingulum angular bundle (all p's ≤ 0.002). In these tracts subjects with ASD tended to have equal or increased FA and/or reduced MD and/or RD at younger ages while controls had increased FA and/or reduced MD and/or RD thereafter. Only for TP individuals, increased FA in the left anterior thalamic radiation was associated with better response inhibition, while reduced RD in forceps minor and left cingulum angular bundle was related to better problem solving and working memory performance respectively. These findings provide novel insight into the age-dependency of EF performance and WMS in ASD, which can be instructive to cognitive training programs.

Analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans in stack gas emissions by gas chromatography-atmospheric pressure chemical ionization-triple-quadrupole mass spectrometry

A gas chromatography coupled to triple-quadrupole mass spectrometry (GC-(QqQ)MS/MS) including a soft-ionization through an atmospheric pressure chemical ionization (APCI) source based method was compared with the high resolution mass spectrometry (HRMS) standard reference method EN1948, for the analysis of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) in stack gas emissions. The stack emission samples were collected, both, by manual method sampling (from 6 to 8h) and by long-term sampling systems (sampling time of several weeks). This work presents the first comparison of GC-(QqQ)MS/MS with APCI source with the European Standard EN1948 technique for stack gas emissions. Sample concentrations ranged from 0.5 to 596pg I-TEQ/Nm³. Comparative results in all investigated samples showed relative errors that were within ±15%. These results make GC-(QqQ)MS/MS with APCI suitable for the quantitative analysis of dioxins in the studied samples and create a real alternative tool to the reference sector GC-HRMS instruments.

Baseline, Two-year, and Five-year Follow-up of Children and Adolescents with First-episode Psychosis: A Spanish Cohort

Background

Early-onset first-episode psychosis (FEP) and high functioning autism spectrum disorders (ASD) are complex neuro–developmental disorders that share symptomatology but it is not clear if they also share neurobiological abnormalities (Chisholm et al., 2015). We examined thickness, surface area and volume in a direct comparison of children and adolescents with FEP (onset before 18 years), high-functioning ASD, and healthy subjects.

Methods

Magnetic resonance imaging scans of 85 participants (30 ASD, 29 FEP, 26 healthy controls, age range 10–18 years) were obtained from the same MR scanner using the same acquisition protocol. The FreeSurfer analysis suite was used to quantify vertex-wise estimates of the metrics thickness, surface area, and volume.

Results

ASD and FEP had spatially overlapping insular deficits for each metric. The transdiagnostic overlap of deficits was greatest for volume (55% of all insular vertices) and smallest for thickness (18%). Insular thickness and surface area deficits did not overlap in ASD and overlapped only in 8% of all insular vertices in FEP.

Conclusions

Morphological insular deficits are common to FEP and high functioning ASD when compared to healthy participants. The pattern of deficits was similar in both disorders, i.e. a largely non-overlap of insular thickness and surface area. The non-overlap provides further evidence that these metrics represent two independent outcomes of corticogenesis, both of which are affected in FEP and ASD.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Enhanced structural connectivity within a brain sub-network supporting working memory and engagement processes after cognitive training

The structural connectome provides relevant information about experience and training-related changes in the brain. Here, we used network-based statistics (NBS) and graph theoretical analyses to study structural changes in the brain as a function of cognitive training. Fifty-six young women were divided in two groups (experimental and control). We assessed their cognitive function before and after completing a working memory intervention using a comprehensive battery that included fluid and crystallized abilities, working memory and attention control, and we also obtained structural MRI images. We acquired and analyzed diffusion-weighted images to reconstruct the anatomical connectome and we computed standardized changes in connectivity as well as group differences across time using NBS. We also compared group differences relying on a variety of graph-theory indices (clustering, characteristic path length, global and local efficiency and strength) for the whole network as well as for the sub-network derived from NBS analyses. Finally, we calculated correlations between these graph indices and training performance as well as the behavioral changes in cognitive function. Our results revealed enhanced connectivity for the training group within one specific network comprised of nodes/regions supporting cognitive processes required by the training (working memory, interference resolution, inhibition, and task engagement). Significant group differences were also observed for strength and global efficiency indices in the sub-network detected by NBS. Therefore, the connectome approach is a valuable method for tracking the effects of cognitive training interventions across specific sub-networks. Moreover, this approach allowsfor the computation of graph theoretical network metricstoquantifythetopological architecture of the brain networkdetected. The observed structural brain changes support the behavioral results reported earlier (see Colom, Román, et al., 2013).

Structural brain connectivity and cognitive ability differences: A multivariate distance matrix regression analysis

Neuroimaging research involves analyses of huge amounts of biological data that might or might not be related with cognition. This relationship is usually approached using univariate methods, and, therefore, correction methods are mandatory for reducing false positives. Nevertheless, the probability of false negatives is also increased. Multivariate frameworks have been proposed for helping to alleviate this balance. Here we apply multivariate distance matrix regression for the simultaneous analysis of biological and cognitive data, namely, structural connections among 82 brain regions and several latent factors estimating cognitive performance. We tested whether cognitive differences predict distances among individuals regarding their connectivity pattern. Beginning with 3,321 connections among regions, the 36 edges better predicted by the individuals' cognitive scores were selected. Cognitive scores were related to connectivity distances in both the full (3,321) and reduced (36) connectivity patterns. The selected edges connect regions distributed across the entire brain and the network defined by these edges supports high-order cognitive processes such as (a) (fluid) executive control, (b) (crystallized) recognition, learning, and language processing, and (c) visuospatial processing. This multivariate study suggests that one widespread, but limited number, of regions in the human brain, supports high-level cognitive ability differences. Hum Brain Mapp 38:803-816, 2017. © 2016 Wiley Periodicals, Inc.

Brain structural changes following adaptive cognitive training assessed by Tensor-Based Morphometry (TBM)

Tensor-Based Morphometry (TBM) allows the automatic mapping of brain changes across time building 3D deformation maps. This technique has been applied for tracking brain degeneration in Alzheimer's and other neurodegenerative diseases with high sensitivity and reliability. Here we applied TBM to quantify changes in brain structure after completing a challenging adaptive cognitive training program based on the n-back task. Twenty-six young women completed twenty-four training sessions across twelve weeks and they showed, on average, large cognitive improvements. High-resolution MRI scans were obtained before and after training. The computed longitudinal deformation maps were analyzed for answering three questions: (a) Are there differential brain structural changes in the training group as compared with a matched control group? (b) Are these changes related to performance differences in the training program? (c) Are standardized changes in a set of psychological factors (fluid and crystallized intelligence, working memory, and attention control) measured before and after training, related to structural changes in the brain? Results showed (a) greater structural changes for the training group in the temporal lobe, (b) a negative correlation between these changes and performance across training sessions (the greater the structural change, the lower the cognitive performance improvements), and (c) negligible effects regarding the psychological factors measured before and after training.

Gray matter responsiveness to adaptive working memory training: a surface-based morphometry study

Here we analyze gray matter indices before and after completing a challenging adaptive cognitive training program based on the n-back task. The considered gray matter indices were cortical thickness (CT) and cortical surface area (CSA). Twenty-eight young women (age range 17-22 years) completed 24 training sessions over the course of 3 months (12 weeks, 24 sessions), showing expected performance improvements. CT and CSA values for the training group were compared with those of a matched control group. Statistical analyses were computed using a ROI framework defined by brain areas distinguished by their genetic underpinning. The interaction between group and time was analyzed. Middle temporal, ventral frontal, inferior parietal cortices, and pars opercularis were the regions where the training group showed conservation of gray matter with respect to the control group. These regions support working memory, resistance to interference, and inhibition. Furthermore, an interaction with baseline intelligence differences showed that the expected decreasing trend at the biological level for individuals showing relatively low intelligence levels at baseline was attenuated by the completed training.

Reproducibility of brain-cognition relationships using three cortical surface-based protocols: An exhaustive analysis based on cortical thickness

People differ in their cognitive functioning. This variability has been exhaustively examined at the behavioral, neural and genetic level to uncover the mechanisms by which some individuals are more cognitively efficient than others. Studies investigating the neural underpinnings of interindividual differences in cognition aim to establish a reliable nexus between functional/structural properties of a given brain network and higher order cognitive performance. However, these studies have produced inconsistent results, which might be partly attributed to methodological variations. In the current study, 82 healthy young participants underwent MRI scanning and completed a comprehensive cognitive battery including measurements of fluid, crystallized, and spatial intelligence, along with working memory capacity/executive updating, controlled attention, and processing speed. The cognitive scores were obtained by confirmatory factor analyses. T1 -weighted images were processed using three different surface-based morphometry (SBM) pipelines, varying in their degree of user intervention, for obtaining measures of cortical thickness (CT) across the brain surface. Distribution and variability of CT and CT-cognition relationships were systematically compared across pipelines and between two cognitively/demographically matched samples to overcome potential sources of variability affecting the reproducibility of findings. We demonstrated that estimation of CT was not consistent across methods. In addition, among SBM methods, there was considerable variation in the spatial pattern of CT-cognition relationships. Finally, within each SBM method, results did not replicate in matched subsamples.

Altered brain rhythms and functional network disruptions involved in patients with generalized fixation-off epilepsy

Generalized Fixation-off Sensitivity (CGE-FoS) patients present abnormal EEG patterns when losing fixation. In the present work, we studied two CGE-FoS epileptic patients with simultaneous EEG-fMRI. We aim to identify brain areas that are specifically related to the pathology by identifying the brain networks that are related to the EEG brain altered rhythms. Three main analyses were performed: EEG standalone, where the voltage fluctuations in delta, alpha, and beta EEG bands were obtained; fMRI standalone, where resting-state fMRI ICA analyses for opened and closed eyes conditions were computed per subject; and, EEG-informed fMRI, where EEG delta, alpha and beta oscillations were used to analyze fMRI. Patient 1 showed EEG abnormalities for lower beta band EEG brain rhythm. Fluctuations of this rhythm were correlated with a brain network mainly composed by temporo-frontal areas only found in the closed eyes condition. Patient 2 presented alterations in all the EEG brain rhythms (delta, alpha, beta) under study when closing eyes. Several biologically relevant brain networks highly correlated (r > 0.7) to each other in the closed eyes condition were found. EEG-informed fMRI results in patient 2 showed hypersynchronized patterns in the fMRI correlation spatial maps. The obtained findings allow a differential diagnosis for each patient and different profiles with respect to healthy volunteers. The results suggest a different disruption in the functional brain networks of these patients that depends on their altered brain rhythms. This knowledge could be used to treat these patients by novel brain stimulation approaches targeting specific altered brain networks in each patient.

Sensation-to-cognition cortical streams in attention-deficit/hyperactivity disorder

We sought to determine whether functional connectivity streams that link sensory, attentional, and higher-order cognitive circuits are atypical in attention-deficit/hyperactivity disorder (ADHD). We applied a graph-theory method to the resting-state functional magnetic resonance imaging data of 120 children with ADHD and 120 age-matched typically developing children (TDC). Starting in unimodal primary cortex-visual, auditory, and somatosensory-we used stepwise functional connectivity to calculate functional connectivity paths at discrete numbers of relay stations (or link-step distances). First, we characterized the functional connectivity streams that link sensory, attentional, and higher-order cognitive circuits in TDC and found that systems do not reach the level of integration achieved by adults. Second, we searched for stepwise functional connectivity differences between children with ADHD and TDC. We found that, at the initial steps of sensory functional connectivity streams, patients display significant enhancements of connectivity degree within neighboring areas of primary cortex, while connectivity to attention-regulatory areas is reduced. Third, at subsequent link-step distances from primary sensory cortex, children with ADHD show decreased connectivity to executive processing areas and increased degree of connections to default mode regions. Fourth, in examining medication histories in children with ADHD, we found that children medicated with psychostimulants present functional connectivity streams with higher degree of connectivity to regions subserving attentional and executive processes compared to medication-naïve children. We conclude that predominance of local sensory processing and lesser influx of information to attentional and executive regions may reduce the ability to organize and control the balance between external and internal sources of information in ADHD.

Sex differences in neocortical structure and cognitive performance: A surface-based morphometry study

On average, men show larger brain volumes than women. Regional differences have been also observed, although most of the available studies apply voxel-based morphometry (VBM). Reports applying surface-based morphometry (SBM) have been focused mainly on cortical thickness (CT). Here we apply SBM for obtaining global and regional indices of CT, cortical surface area (CSA), and cortical gray matter volume (CGMV) from samples of men (N=40) and women (N=40) matched for their performance on four cognitive factors varying in their complexity: processing speed, attention control, working memory capacity, and fluid intelligence. These were the main findings: 1) CT and CSA produced very weak correlations in both sexes, 2) men showed larger values in CT, CSA, and CGMV, and 3) cognitive performance was unrelated to brain structural variation within sexes. Therefore, we found substantial group differences in brain structure, but there was no relationship with cognitive performance both between and within-sexes.

Disparate connectivity for structural and functional networks is revealed when physical location of the connected nodes is considered

Macroscopic brain networks have been widely described with the manifold of metrics available using graph theory. However, most analyses do not incorporate information about the physical position of network nodes. Here, we provide a multimodal macroscopic network characterization while considering the physical positions of nodes. To do so, we examined anatomical and functional macroscopic brain networks in a sample of twenty healthy subjects. Anatomical networks are obtained with a graph based tractography algorithm from diffusion-weighted magnetic resonance images (DW-MRI). Anatomical connections identified via DW-MRI provided probabilistic constraints for determining the connectedness of 90 different brain areas. Functional networks are derived from temporal linear correlations between blood-oxygenation level-dependent signals derived from the same brain areas. Rentian Scaling analysis, a technique adapted from very-large-scale integration circuits analyses, shows that functional networks are more random and less optimized than the anatomical networks. We also provide a new metric that allows quantifying the global connectivity arrangements for both structural and functional networks. While the functional networks show a higher contribution of inter-hemispheric connections, the anatomical networks highest connections are identified in a dorsal-ventral arrangement. These results indicate that anatomical and functional networks present different connectivity organizations that can only be identified when the physical locations of the nodes are included in the analysis.

Subcortical regional morphology correlates with fluid and spatial intelligence

Neuroimaging studies have revealed associations between intelligence and brain morphology. However, researchers have focused primarily on the anatomical features of the cerebral cortex, whereas subcortical structures, such as the basal ganglia (BG), have often been neglected despite extensive functional evidence on their relation with higher-order cognition. Here we performed shape analyses to understand how individual differences in BG local morphology account for variability in cognitive performance. Structural MRI was acquired in 104 young adults (45 men, 59 women, mean age = 19.83, SD = 1.64), and the outer surface of striatal structures (caudate, nucleus accumbens, and putamen), globus pallidus, and thalamus was estimated for each subject and hemisphere. Further, nine cognitive tests were used to measure fluid (Gf), crystallized (Gc), and spatial intelligence (Gv). Latent scores for these factors were computed by means of confirmatory factor analysis and regressed vertex-wise against subcortical shape (local displacements of vertex position), controlling for age, sex, and adjusted for brain size. Significant results (FDR < 5%) were found for Gf and Gv, but not Gc, for the right striatal structures and thalamus. The main results show a relative enlargement of the rostral putamen, which is functionally connected to the right dorsolateral prefrontal cortex and other intelligence-related prefrontal areas.

Reversed hierarchy in the brain for general and specific cognitive abilities: a morphometric analysis

Intelligence is composed of a set of cognitive abilities hierarchically organized. General and specific abilities capture distinguishable, but related, facets of the intelligence construct. Here, we analyze gray matter with three morphometric indices (volume, cortical surface area, and cortical thickness) at three levels of the intelligence hierarchy (tests, first-order factors, and a higher-order general factor, g). A group of one hundred and four healthy young adults completed a cognitive battery and underwent high-resolution structural MRI. Latent scores were computed for the intelligence factors and tests were also analyzed. The key finding reveals substantial variability in gray matter correlates at the test level, which is substantially reduced for the first-order and the higher-order factors. This supports a reversed hierarchy in the brain with respect to cognitive abilities at different psychometric levels: the greater the generality, the smaller the number of relevant gray matter clusters accounting for individual differences in intelligent performance.

Cranioplasty with bandaging. New forms of limitation of life support and organ donation

Most of transplanted organs are obtained from brain death (BD) donors. In neurocritical patients with catastrophic injuries and decompressive craniectomy (DC), which show a dreadful development in spite of this treatment, DC could be a futile tool to avoid natural progress to BD. We propose if cranial compressive bandage (cranioplasty with bandage) could be an ethically correct practice, similar to other life-sustaining treatment limitation (LSTL) common methods. Based on a clinical case, we contacted with the Assistance Ethics Committee and some bioethics professionals asking them two questions: 1) Is ethically correct to perform a cranioplasty with bandage in those patients with LSTL indication? 2) Thinking in organ donation possibility, is this option preferable? Conclusions 1) Cranioplasty with bandage could be considered an ethically acceptable LSTL practice, similar to other procedures. 2) It facilitates organ donation for transplant, which provides value-added because of its own social good. 3) In these cases, it is necessary to know previous patient's will or, in absentia, to obtain family consent after a detailed procedure report.

Analytical approach and occurrence for the determination of mass concentration of PCDD/PCDF and dl-PCB in flue gas emissions using long-term sampling devices

In this work, a reliable methodology for the simultaneous analysis of PCDD/PCDF and dioxin-like PCB (dl-PCB) in flue gas emissions collected using continuous sampling devices is proposed. The analytical scheme followed the minimum requirements described in the EU standard EN-1948:1,2,3,4 according to samples containing large amounts of dioxins and dl-PCBs or samples collected over a long period of time of about 4 weeks. Parameters, such as reproducibility, precision, limits of detection (LOD), limits of quantification (LOQ), extract aliquot size, analytical blanks, extraction efficiency, as well as the amount of internal standards required for an accurate determination, were assessed. The findings demonstrate the suitability of the proposed analytical scheme for the analysis of PCDD/PCDF and PCB in samples collected using long-term sampling devices. The analysis of five different 5% v/v sample aliquots reported %RSD values lower than 10% for all of the 29 congeners at both low and high levels. Similarly, %RSD values were 3.2 and 2.0 for the low level samples and 0.9 and 1.1%RSD for the high level extracts for PCDD/PCDF and dl-PCB, respectively expressed in total TEQ units. Re-extraction provided values less than 3%, expressed in TEQ. Based on blank analyses, LOD values of 100 pg I-TEQ for PCDD/PCDF and 10 pg WHO-TEQ for dl-PCB were achieved when 5% v/v aliquots were analyzed. Finally, the proposed analytical approach was tested with samples from a wide range of combustion processes such as hazardous and municipal waste incinerators, as well as cement kilns (with and without waste co-incineration).

Changes in resting-state functionally connected parietofrontal networks after videogame practice

Neuroimaging studies provide evidence for organized intrinsic activity under task-free conditions. This activity serves functionally relevant brain systems supporting cognition. Here, we analyze changes in resting-state functional connectivity after videogame practice applying a test-retest design. Twenty young females were selected from a group of 100 participants tested on four standardized cognitive ability tests. The practice and control groups were carefully matched on their ability scores. The practice group played during two sessions per week across 4 weeks (16 h total) under strict supervision in the laboratory, showing systematic performance improvements in the game. A group independent component analysis (GICA) applying multisession temporal concatenation on test-retest resting-state fMRI, jointly with a dual-regression approach, was computed. Supporting the main hypothesis, the key finding reveals an increased correlated activity during rest in certain predefined resting state networks (albeit using uncorrected statistics) attributable to practice with the cognitively demanding tasks of the videogame. Observed changes were mainly concentrated on parietofrontal networks involved in heterogeneous cognitive functions.

[Ethics of the cardiopulmonary resuscitation decisions]

Cardiopulmonary Resuscitation (CPR) must be attempted if indicated, not done if it is not indicated or if the patient does not accept or has previously rejected it and withdrawn it if it is ineffective. If CPR is considered futile, a Do-Not-Resuscitate Order (DNR) will be recorded. This should be made known to all physicians and nurses involved in patient care. It may be appropriate to limit life-sustaining-treatments for patients with severe anoxic encephalopathy, if the possibility of clinical evolution to brain death is ruled out. After CPR it is necessary to inform and support families and then review the process in order to make future improvements. After limitation of vital support, certain type of non-heart-beating-organ donation can be proposed. In order to acquire CPR skills, it is necessary to practice with simulators and, sometimes, with recently deceased, always with the consent of the family. Research on CPR is essential and must be conducted according to ethical rules and legal frameworks.

Caracterización fenotípica del genofondo avícola criollo de San andrés, Pinar del río, Cuba

El objetivo de este trabajo fue estimar por el método de observación la frecuencia de aparición de algunos rasgos de apariencia fenotípica de la gallina Criolla (Gallus gallus) en tres zonas del valle San Andrés del municipio La Palma, en la provincia de Pinar del Río, para aportar a la caracterización fenotípica de este genofondo avícola criollo. Como resultado se identificaron 28 caracteres agrupados en 8 rasgos de apariencia fenotípica (color del plumaje, tipo de plumaje, tipo de cresta color de los tarsos, presencia de patas plumosas, color de la piel, color del pico y color de las orejuelas). Los resultados de este trabajo han orientado el desarrollo de otras investigaciones con el propósito de evaluar la adaptabilidad y productividad de este genofondo avícola y su posible asociación con los rasgos de apariencia fenotípica encontrados.

Caracterización fenotípica del genofondo avícola criollo de San andrés, Pinar del río, Cuba

El objetivo de este trabajo fue estimar por el método de observación la frecuencia de aparición de algunos rasgos de apariencia fenotípica de la gallina Criolla (Gallus gallus) en tres zonas del valle San Andrés del municipio La Palma, en la provincia de Pinar del Río, para aportar a la caracterización fenotípica de este genofondo avícola criollo. Como resultado se identificaron 28 caracteres agrupados en 8 rasgos de apariencia fenotípica (color del plumaje, tipo de plumaje, tipo de cresta color de los tarsos, presencia de patas plumosas, color de la piel, color del pico y color de las orejuelas). Los resultados de este trabajo han orientado el desarrollo de otras investigaciones con el propósito de evaluar la adaptabilidad y productividad de este genofondo avícola y su posible asociación con los rasgos de apariencia fenotípica encontrados.

Baseline levels of dioxin and furan emissions from waste thermal treatment in Colombia

Background data of polychlorinated dibenzodioxin and dibenzofuran (PCDD/Fs) emissions from the incineration sector in Colombia are presented. Monitoring was carried out during a two-year period, 2003-2005. Twelve plants were sampled for stack gas emissions of dioxins and total solid particulate (TSP). Additionally, PCDD/Fs in several fly ash samples were analyzed. Most incinerators burned industrial refuse materials and medical residues. A wide range of PCDD/Fs emission levels were found. In particular, levels ranging from 6.9 to 343.8 ng I-TEQ/N m(3) were determined in plants without any air pollution control system (APCS). In contrast, 0.5-39.2 ng I-TEQ/N m(3) levels were found in plants with APCS while 8.5-67.5 ng I-TEQ/g were measured in fly ash samples. TSP values ranged from 14 to 448 mg/N m(3). This study also evaluated the impact of implementing different control systems in an incinerator. Finally, for comparison purposes several samples were analyzed by both high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC-HRMS) and high resolution gas chromatography coupled to ion-trap low resolution mass spectrometry-mass spectrometry (HRGC-IT LRMS/MS). Overall, I-TEQ values deviated about 20-30% between both techniques.

[Quality of care for the dying in a hospital]

Aim. To analyse the accounts of the relatives of patients who died during one year in a hospital in Navarre, within a study of the quality of care for the dying. Method. A telephone interview was conducted with the person dearest to the patients who had died in the course of one year in the hospital. The TOOLKIT survey, previously validated, was used to this end. In all cases a maximum of three calls was made to establish contact with the person to be interviewed. The calls were made between three and six months following the death of the patient. The first part of the interview was aimed at providing information about the aim of the study and informed consent was requested. Four fields were analysed: physical and emotional comfort, shared decision making, respect and dignity, and care of the carers. The interview ended with an open question: Do you wish to add anything else? Results. The number of persons interviewed was 327. For the 712 deceased in the hospital who met the requirements, 320 persons could not be located and another 65 refused to be interviewed. Many complaints were gathered concerning the quantity and quality of information and the manner and time of its provision. There were also complaints concerning respect for the wishes of the patient, the management of pain, dyspnoea and personal treatment received. The lack of emotional support perceived by the relatives is also important. Conclusions. Besides the numerical variables contained in the survey, we believe that the narrative that a survey can contain provides key information for the analysis of care quality.

[The living will]

The importance of decision making that is informed and shared between the patient and the health professional caring for him/her is essential for the quality of care and its results. Living wills are no more than a concrete expression of this reality. Their legal acceptance has meant recognition of respect for the autonomy of patients. However, the laws passed contain some incongruities and the health practice related to these documents suffers from numerous practical and ethical problems on which reflection is invited. The article concludes by recommending the adoption of measures aimed at strengthening the advance planning of health care, a question that requires profound changes in the training of professionals and in the policies of the health institutions.