Do catadromous thinlip grey mullet benefit from shifting to freshwater? A perspective from fatty acid signature analysis

To investigate the potential benefits of the catadromous thinlip grey mullet (Chelon ramada Risso, 1827) migration to freshwater, the total lipid content and fatty acid (FA) profile of female's muscle and gonads caught in both the estuary and river were analyzed. The freshwater contingent presented a higher body condition, greater muscle gross energy, and larger gonads with higher lipid reserves. These animals showed a muscle profile rich in C16:1n-7 and lower LC-PUFA that contrast with the higher relative amount of C18:1n-9, n-3 FA, and unsaturated LC-PUFA, such as C18 and C20 FA found in the estuarine contingent. The gonads of both contingents showed a constant and high relative amount of polyunsaturated FAs (PUFA, 37%). However, in terms of essential fatty acids (EFAs), the estuarine contingent had a higher relative amount of C18:2n-6, C20:4n-6, C20:5n-3, and C22:6n-3. On the other hand, the freshwater contingent showed a higher relative amount of n-3 FA precursors, namely C18:3n-3, and a still low relative amount of C22:6n-3. This suggests a mismatch between the metabolic omega-3 pathway and the physiological maturity stages, similar to a phenomenon of dormancy. In this sense, not all these individuals may reproduce annually, and the later stages of gonad development will require supplementary energy derived from feeding at the estuary. Thus, freshwater migration may promote a reproductive strategy enabling adults to take advantage of the warm and food-rich summer/autumn period, adjust spawning and juvenile appearance, and reduce the population's exposure to habitat changes and/or stochastic events.

Amplitude modulation of the contingent negative variation in psychopathy: A systematic review and meta-analysis

The CNV is analyzed in tasks related to EEG studies, often with participants presenting psychopathic personality traits. A systematic search of the literature was conducted, to solve some inconsistencies regarding CNV amplitude modulation by psychopathy. Nine studies (N = 317) were retrieved for analysis. Three meta-analyses were run - CNV, iCNV, tCNV. A qualitative analysis - reporting CNV amplitudes modulated by psychopathy dimensional features - was also featured. Overall effects for CNV and iCNV were not significant. Larger tCNV amplitudes were found in participants reporting higher psychopathy traits, g = -0.58, 95% CI [- 0.94, - 0.22]. These findings were surprising when confronted with previous assumptions in the literature, especially considering that no significant heterogeneity between studies was found. Neither of the studies' characteristics was a significant moderator. Findings require the need to discuss key differences between adaptive/(mal)adjustment patterns in participants presenting psychopathic traits. Future studies dissociating iCNV and tCNV modulation by psychopathy, especially in community samples and through a dimensional lens, could help to better understand the construct of psychopathy.

Seascape genomics reveals limited dispersal and suggests spatially varying selection among European populations of sea lamprey (Petromyzon marinus)

Sea lamprey Petromyzon marinus is an anadromous and semelparous fish without homing behaviors. Despite being a freshwater, free-living organism for a large part of their life cycle, its adulthood is spent as a parasite of marine vertebrates. In their native European range, while it is well-established that sea lampreys comprise a single nearly-panmictic population, few studies have further explored the evolutionary history of natural populations. Here, we performed the first genome-wide characterization of sea lamprey's genetic diversity in their European natural range. The objectives were to investigate the connectivity among river basins and explore evolutionary processes mediating dispersal during the marine phase, with the sequencing of 186 individuals from 8 locations spanning the North Eastern Atlantic coast and the North Sea with double-digest RAD-sequencing, obtaining a total of 30,910 bi-allelic SNPs. Population genetic analyses reinforced the existence of a single metapopulation encompassing freshwater spawning sites within the North Eastern Atlantic and the North Sea, though the prevalence of private alleles at northern latitudes suggested some limits to the species' dispersal. Seascape genomics suggested a scenario where oxygen concentration and river runoffs impose spatially varying selection across their distribution range. Exploring associations with the abundance of potential hosts further suggested that hake and cod could also impose selective pressures, although the nature of such putative biotic interactions was unresolved. Overall, the identification of adaptive seascapes in a panmictic anadromous species could contribute to conservation practices by providing information for restoration activities to mitigate local extinctions on freshwater sites.

Boldness Personality Traits Are Associated With Reduced Risk Perceptions and Adoption of Protective Behaviors During the First COVID-19 Outbreak

The containment measures imposed during the first COVID-19 outbreak required economic, social, and behavioral changes to minimize the spread of the coronavirus. Some studies have focused on how personality predicts distinct patterns of adherence to protective measures with psychopathic and antisocial traits predicting reduced engagement in such measures. In this study we extended previous findings by analyzing how boldness, meanness, and disinhibition psychopathic traits relate with both risk perceptions and protective behaviors during the first COVID-19 outbreak. A sample of 194 individuals (24% male) engaged in the survey, were assessed for psychopathic traits with the Triarchic Psychopathy Measure, and completed a COVID-19 survey targeting risk perceptions (spread, risk of becoming infected, state anxiety toward the COVID-19, and perceived risk of specific behaviors) and frequency of protective behaviors (e.g., not engaging in social distancing). Overall results show that boldness predicts reduced estimate of COVID-19 spread, reduced perceived risk of becoming infected, reduced state anxiety toward COVID-19, and reduced frequency of protective behaviors. Exploratory mediation models suggest that risk perceptions are not significant mediators of the association between psychopathic traits and reduced engagement in protective behaviors. Our results unveil that psychopathic traits affect risk perceptions and the propensity to engage in protective measures, emphasizing the need to accommodate these personality features in the public health strategy to control the COVID-19 spread.

Callous-Unemotional Traits Moderate Anticipated Guilt and Wrongness Judgments to Everyday Moral Transgressions in Adolescents

Callous-unemotional (CU) traits observed during childhood and adolescence are thought to be precursors of psychopathic traits in adulthood. Adults with high levels of psychopathic traits typically present antisocial behavior. Such behavior can be indicative of atypical moral processing. Evidence suggests that moral dysfunction in these individuals may stem from a disruption of affective components of moral processing rather than from an inability to compute moral judgments per se. No study to date has tested if the dissociation between affective and cognitive dimensions of moral processing linked to psychopathic traits in adulthood is also linked to CU traits during development. Here, 47 typically developing adolescents with varying levels of CU traits completed a novel, animated cartoon task depicting everyday moral transgressions and indicated how they would feel in such situations and how morally wrong the situations were. Adolescents with higher CU traits reported reduced anticipated guilt and wrongness appraisals of the transgressions. However, our key finding was a significant interaction between CU traits and anticipated guilt in predicting wrongness judgments. The strength of the association between anticipated guilt and wrongness judgement was significantly weaker for those with higher levels of CU traits. This evidence extends our knowledge on the cognitive-affective processing deficits that may underlie moral dysfunction in youth who are at heightened risk for antisocial behavior and psychopathy in adulthood. Future longitudinal research is required to elucidate whether there is an increased dissociation between different components of moral processing from adolescence to adulthood for those with high psychopathic traits.

Further evaluation of the Triarchic Psychopathy Measure: Evidence from community adult and prisoner samples from Portugal

The Triarchic Measure of Psychopathy (TriPM) was developed to assess manifest expressions of biobehavioural liabilities relevant to psychopathy and other forms of mental illness. Psychometric findings have been examined for a number of international translations of the TriPM, but further work is needed to evaluate its cross-cultural applicability and its properties in clinical versus nonclinical samples. The present study sought to evaluate the reliability and criterion-related validity and characterize the internal factor structure of the European Portuguese version of the TriPM in a large community sample (N = 1,833), and examine its ability to differentiate between community and prisoner (N = 240) samples. Reliability and criterion-related validity analysis supported the TriPM as an effective measure of psychopathic traits. Internal structure was characterized using exploratory structural equation modeling to specify bifactor models for the TriPM's three subscales and for the inventory as a whole; the model for each subscale included a general factor and a variable number of specific factors as determined by parallel analysis. These modeling analyses demonstrated unidimensionality for each TriPM subscale, and provided support for the triarchic structure of the TriPM as a whole. Additionally, Receiver Operating Characteristics analysis showed that the disinhibition score, as assessed by the TriPM, is the most sensitive for differentiating between prisoner and community samples. Our results are in line with other reports regarding the psychometric properties of the TriPM and provide further evidence for the construct validity of the TriPM. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Primary and secondary oocyte growth dynamics in anadromous semelparous Allis shad Alosa alosa

We analysed the ovarian dynamics of the anadromous semelparous allis shad Alosa alosa for which our working hypothesis was that mature pre-spawning females would have very low or even exhausted primary growth (PG) oocyte reserves; semelparity has been linked with the depletion of the pool of PG oocytes. To test this hypothesis, the PG oocytes were enumerated, their recruitment pattern to the secondary growth (SG) phase was analysed and their potential replenishment from the pool of oogonia was examined in females caught very close to the Mondego River mouth, in central Portugal and along the river. The development of the SG oocytes was also analysed, the fecundity (batch, total and annual) values were estimated and the intensity of atresia was quantified. Ovarian samples and histological sections were investigated in parallel. A dynamic recruitment pattern of PG oocytes to the SG phase was revealed, where all PG oocytes were recruited and were not replenished by oogonia. Annual fecundity was subject to down-regulation due to atresia prior to spawning and its size was multiple times higher than the size of batch fecundity. Lack of population synchronicity in ovarian development and spawning migration was also observed. This multifaceted analysis of the ovarian dynamics of this species will contribute to management efforts for this critically endangered and economically important fish throughout its geographical distribution. The results reported in this study will also assist in unravelling the complexity of the early processes of oogenesis in fish.

Validation of Wireless Sensors for Psychophysiological Studies

James One (MindProber Labs) is a wireless psychophysiological device comprising two sensors: one measuring electrodermal activity (EDA), the other photoplethysmography (PPG). This paper reports the validation of James One’s EDA sensor by comparing its signal against a research grade polygraph. Twenty participants were instructed to perform breathing exercises to elicit the modulation of EDA and heart rate, while the physiological signal was captured simultaneously on James One and a Biopac MP36. The resulting EDA and PPG records collected from both systems were comprehensively compared. Results suggest that James One captures EDA signal with a quality comparable to a research grade equipment, this constituting a reliable means of capturing data while minimizing setup time and intrusiveness.

Muscle fatty acid profiles of sea lamprey (Petromyzon marinus L.) indicate the use of fast metabolized energy during ontogenesis

A comprehensive characterization of muscle's FA composition of sea lamprey ammocoetes and adults was performed to test the hypothesis that larvae, and early spawning migrants have a similar FA profile prior to metamorphosis and to spawning migration. Subsequently, the role played by FA signature in these two highly demanding stages of life cycle was inferred. The results confirm that muscle represents an important fat reservoir, and the FA trophic markers revealed the importance of bacteria as sources of iso and anteiso FA and the strong trophic representation of benthic phytoplankton (diatoms) to larvae muscle FA profile. In early spawning migrants, the significance of marine food web to FA muscle profile is highlighted by the presence of FA signatures characteristics of herbivorous calanoid copepods. Although both life cycle phases studied do not share the same muscle FA signature, there is a part of the profile that is common, which is characterized by FA used in β-oxidation, such as C18:1ω9 but also by medium chain FA and PUFA which points that PUFA are spared as fuel to β-oxidation process and probably used to the development of tissues membranes (ammocoetes) and gonadal development and eicosanoid production among others (early spawning migrants). Further studies on FA profile are necessary to elucidate the FA role either during different life stages (ontogeny) or in the distinct habitats frequented (freshwater versus marine) by this diadromous species.

A phenomenological analysis of eco-evolutionary coupling under dilution

Evolutionary dynamics experienced by mixed microbial populations of cooperators and cheaters has been examined in experiments in the literature using a protocol of periodic dilution to investigate the properties of resilience and adaptability to environmental changes. Data depicted on an appropriate phase diagram indicate, among other features, a stable equilibrium point at which cooperators and cheaters coexist (Sanchez and Gore, 2013). We present here a phenomenological analysis of these data focusing on an eco-evolutionary-game perspective. To that end, we work on an extension of the model proposed in Tao and Cressman (2007). It's original version takes into account changes of the total population density while the individuals experience a pairwise Prisoners Dilemma game. The extension devised here contains a dilution parameter to conform with the experimental procedure, in addition to a term accounting for Allee effects. In contrast to other descriptions proposed in similar contexts, however, the model here does not account for assortative encounters, group or kin selection. Nonetheless, it describes surprisingly well both qualitatively and quantitatively the features of the observed phase diagram. We discuss these results in terms of the behavior of an effective payoff matrix defined accordingly.

Heart rate variability metrics for fine-grained stress level assessment

BACKGROUND AND OBJECTIVES

In spite of the existence of a multitude of techniques that allow the estimation of stress from physiological indexes, its fine-grained assessment is still a challenge for biomedical engineering. The short-term assessment of stress condition overcomes the limits to stress characterization with long blocks of time and allows to evaluate the behaviour change in real-world settings and also the stress level dynamics. The aim of the present study was to evaluate time and frequency domain and nonlinear heart rate variability (HRV) metrics for stress level assessment using a short-time window.

METHODS

The electrocardiogram (ECG) signal from 14 volunteers was monitored using the Vital Jacket^TM while they performed the Trier Social Stress Test (TSST) which is a standardized stress-inducing protocol. Window lengths from 220 s to 50 s for HRV analysis were tested in order to evaluate which metrics could be used to monitor stress levels in an almost continuous way.

RESULTS

A sub-set of HRV metrics (AVNN, rMSSD, SDNN and pNN20) showed consistent differences between stress and non-stress phases, and showed to be reliable parameters for the assessment of stress levels in short-term analysis.

CONCLUSIONS

The AVNN metric, using 50 s of window length analysis, showed that it is the most reliable metric to recognize stress level across the four phases of TSST and allows a fine-grained analysis of stress effect as an index of psychological stress and provides an insight into the reaction of the autonomic nervous system to stress.

Impact of Chronic Stress Protocols in Learning and Memory in Rodents: Systematic Review and Meta-Analysis

The idea that maladaptive stress impairs cognitive function has been a cornerstone of decades in basic and clinical research. However, disparate findings have reinforced the need to aggregate results from multiple sources in order to confirm the validity of such statement. In this work, a systematic review and meta-analyses were performed to aggregate results from rodent studies investigating the impact of chronic stress on learning and memory. Results obtained from the included studies revealed a significant effect of stress on global cognitive performance. In addition, stressed rodents presented worse consolidation of learned memories, although no significantly differences between groups at the acquisition phase were found. Despite the methodological heterogeneity across studies, these effects were independent of the type of stress, animals’ strains or age. However, our findings suggest that stress yields a more detrimental effect on spatial navigation tests’ performance. Surprisingly, the vast majority of the selected studies in this field did not report appropriate statistics and were excluded from the quantitative analysis. We have therefore purposed a set of guidelines termed PROBE (Preferred Reporting Orientations for Behavioral Experiments) to promote an adequate reporting of behavioral experiments.

Using signal detection theory in the analysis of emotional sensitivity of male recidivist offenders

BACKGROUND

Study of emotional responses of antisocial individuals has produced inconsistent findings. Some studies report emotional deficits, while others find no differences between people with and without antisocial behaviours.

AIMS

Our aim was to apply signal detection theory methods to compare the sensitivity of antisocial and control participants to emotional stimuli. We hypothesised that offenders would show lower ability to discriminate changes in the level of arousal and valence of emotional stimuli relative to the controls.

METHODS

Signal detection theory was applied to study the sensitivity of recidivist offenders in prison to emotional arousal and valence induced by pictures. This approach, novel in this context, provides a departure from the usual reliance on self-report.

RESULTS

Offenders reported higher arousal than controls but showed lower sensitivity to changes between different levels of arousal (whereas no differences were found for valence). Also, offenders showed increased response bias for changes in the levels of arousal, as well as in the higher levels of valence.

CONCLUSIONS

Our findings show that direct observations of emotional arousal, but not valence, discriminate between recidivist offenders with antisocial personality disorder and non-offending controls. Use of such approaches is likely to provide more valid data than self-reports and may prove particularly useful in studies of intervention for recidivists or in assessment of their readiness for release.

Psychopathic traits are associated with cortical and subcortical volume alterations in healthy individuals

Research suggests psychopathy is associated with structural brain alterations that may contribute to the affective and interpersonal deficits frequently observed in individuals with high psychopathic traits. However, the regional alterations related to different components of psychopathy are still unclear. We used voxel-based morphometry to characterize the structural correlates of psychopathy in a sample of 35 healthy adults assessed with the Triarchic Psychopathy Measure. Furthermore, we examined the regional grey matter alterations associated with the components described by the triarchic model. Our results showed that, after accounting for variation in total intracranial volume, age and IQ, overall psychopathy was negatively associated with grey matter volume in the left putamen and amygdala. Additional regression analysis with anatomical regions of interests revealed total triPM score was also associated with increased lateral orbitofrontal cortex (OFC) and caudate volume. Boldness was positively associated with volume in the right insula. Meanness was positively associated with lateral OFC and striatum volume, and negatively associated with amygdala volume. Finally, disinhibition was negatively associated with amygdala volume. Results highlight the contribution of both subcortical and cortical brain alterations for subclinical psychopathy and are discussed in light of prior research and theoretical accounts about the neurobiological bases of psychopathic traits.

Similar sound intensity dependence of the N1 and P2 components of the auditory ERP: Averaged and single trial evidence

OBJECTIVE

The literature suggests that the N1 and P2 waves of the auditory ERP are dissociable at the developmental, experimental, and source levels. At the experimental level, inconsistent findings suggest different effects of intensity on the amplitudes of the auditory N1 and P2. Our main goal was to analyze the intensity dependence of the auditory N1 and P2 while controlling for habituation effects.

METHODS

We examined the intensity dependence of both averaged and single-trial auditory N1 and P2 waves elicited in a repeated-stimulation protocol.

RESULTS

N1 and P2 revealed similar intensity dependence on both standard and filter denoised ERP, with a linear tendency for higher intensities to elicit higher absolute peak amplitudes. At the single-trial level, both waves covary irrespective of stimulus intensity and trial order.

CONCLUSIONS

Our results suggest that stimulus intensity variation induces similar effects on both and N1 and P2 and partially contradict previous data that classified the P2 as a non-habituating component.

SIGNIFICANCE

Our findings contribute to the ongoing discussion on the functional significance of the auditory P2 deflection. In addition, the present work demonstrated the applicability of a filter denoising method for single-trial estimation in the analysis of the experimental effects on auditory ERP components.

Investigating population structure of Sea Lamprey (Petromyzon marinus, L.) in Western Iberian Peninsula using morphological characters and heart fatty acid signature analyses

This study hypothesizes the existence of three groups of sea lamprey Petromyzon marinus L. in Portugal (North/Central group, Tagus group, and Guadiana group), possibly promoted by seabed topography isolation during the oceanic phase of the life cycle. Within this context, our purpose was to analyze the existence of a stock structure on sea lamprey populations sampled in the major Portuguese river basins using both morphological characters and heart tissue fatty acid signature. In both cases, the multiple discriminant analysis revealed statistically significant differences among groups, and the overall corrected classification rate estimated from cross-validation procedure was particularly high for the cardiac muscle fatty acid profiles (i.e. 83.8%). Morphometric characters were much more useful than meristic ones to discriminate stocks, and the most important variables for group differentiation were eye length, second dorsal fin length and branchial length. Fatty acid analysis showed that all lampreys from the southern Guadiana group were correctly classified and not mixing with individuals from any other group, reflecting a typical heart fatty acid signature. Our results revealed that 89.5% and 72.2% of the individuals from the Tagus and North/Central groups, respectively, were also correctly classified, despite some degree of overlap between individuals from these groups. The fatty acids that contributed to the observed segregation were C16:0; C17:0; C18:1ω9; C20:3ω6 and C22:2ω6. Detected differences are probably related with environmental variables to which lampreys may have been exposed, which leaded to different patterns of gene expression. These results suggest the existence of three different sea lamprey stocks in Portugal, with implication in terms of management and conservation.

Strong genome-wide divergence between sympatric European river and brook lampreys

Lampreys, together with hagfishes, are the only extant representatives of jawless vertebrates and thus of prime interest for the study of vertebrate evolution [1]. Most lamprey genera occur in two forms with divergent life histories: a parasitic, anadromous and a non-parasitic, freshwater resident form [2-8]. The taxonomic status of such 'paired species' is disputed, however. While indistinguishable at larval stages, but clearly distinct as adults, they cannot be differentiated with available genetic data [6,7], which has fuelled speculations that the two forms may in fact represent products of phenotypic plasticity within a single species. Here, we use restriction site-associated DNA sequencing (RADseq) to examine the genetic population structure of sympatric European river (Lampetra fluviatilis L., 1758) and brook (Lampetra planeri Bloch, 1784) lampreys. We find strong genetic differentiation and identify numerous fixed and diagnostic single nucleotide polymorphisms (SNPs) between the two species, 12 of which can be unequivocally assigned to specific genes.

Distinct neural activation patterns underlie economic decisions in high and low psychopathy scorers

Psychopathic traits affect social functioning and the ability to make adaptive decisions in social interactions. This study investigated how psychopathy affects the neural mechanisms that are recruited to make decisions in the ultimatum game. Thirty-five adult participants recruited from the community underwent functional magnetic resonance imaging scanning while they performed the ultimatum game under high and low cognitive load. Across load conditions, high psychopathy scorers rejected unfair offers in the same proportion as low scorers, but perceived them as less unfair. Among low scorers, the perceived fairness of offers predicted acceptance rates, whereas in high scorers no association was found. Imaging results revealed that responses in each group were associated with distinct patterns of brain activation, indicating divergent decision mechanisms. Acceptance of unfair offers was associated with dorsolateral prefrontal cortex activity in low scorers and ventromedial prefrontal cortex activity in high scorers. Overall, our findings point to distinct motivations for rejecting unfair offers in individuals who vary in psychopathic traits, with rejections in high psychopathy scorers being probably induced by frustration. Implications of these results for models of ventromedial prefrontal cortex dysfunction in psychopathy are discussed.

Similarity boosted quantitative structure-activity relationship--a systematic study of enhancing structural descriptors by molecular similarity

The concept of molecular similarity is one of the most central in the fields of predictive toxicology and quantitative structure-activity relationship (QSAR) research. Many toxicological responses result from a multimechanistic process and, consequently, structural diversity among the active compounds is likely. Combining this knowledge, we introduce similarity boosted QSAR modeling, where we calculate molecular descriptors using similarities with respect to representative reference compounds to aid a statistical learning algorithm in distinguishing between different structural classes. We present three approaches for the selection of reference compounds, one by literature search and two by clustering. Our experimental evaluation on seven publicly available data sets shows that the similarity descriptors used on their own perform quite well compared to structural descriptors. We show that the combination of similarity and structural descriptors enhances the performance and that a simple stacking approach is able to use the complementary information encoded by the different descriptor sets to further improve predictive results. All software necessary for our experiments is available within the cheminformatics software framework AZOrange.

Three new cryptic species of the lamprey genus Lampetra Bonnaterre, 1788 (Petromyzontiformes: Petromyzontidae) from the Iberian Peninsula

The Iberian Peninsula is a repository for biodiversity, presenting high levels of endemism in both plants and animals. In this peninsular region, brook lampreys confined to small, isolated river basins evolved in allopatry giving rise to evolutionary lineages, as revealed by mitochondrial DNA markers. For a better understanding of the taxonomic status and relationships of Iberian populations of the genus Lampetra, we combined previous data from genetics and morphological analysis (assessed here), and describe three new species of the lamprey genus Lampetra Bonnaterre, 1788 in Portugal. In this region L. planeri actually represent a complex of cryptic species, each having smaller geographic ranges than L. planeri, and consequently, greater vulnerability to extinction. The description of Lampetra alavariensis sp. nov. is based on 36 specimens collected on Ribeira de Mangas, a tributary of river Esmoriz, in Northern Portugal. Lampetra auremensis sp. nov. is described on the basis of 31 specimens collected on Ribeira do Olival, a small tributary of river Nabão (Tagus basin). Finally, Lampetra lusitanica sp. nov. is described based on 38 specimens from Ribeira da Marateca, Sado river basin, the southernmost distribution of the genus Lampetra. The recognition of these new species will contribute to the conservation of these already imperilled taxa and will help prevent the extinction of three important evolutionary lineages.

The auditory P200 is both increased and reduced in schizophrenia? A meta-analytic dissociation of the effect for standard and target stimuli in the oddball task

OBJECTIVE

Conflicting reports of P200 amplitude and latency in schizophrenia have suggested that this component is increased, reduced or does not differ from healthy subjects. A systematic review and meta-analysis were undertaken to accurately describe P200 deficits in auditory oddball tasks in schizophrenia.

METHODS

A systematic search identified 20 studies which were meta-analyzed. Effect size (ES) estimates were obtained: P200 amplitude and latency for target and standard tones at midline electrodes.

RESULTS

The ES obtained for amplitude (Cz) for standard and target stimuli indicate significant effects in opposite directions: standard stimuli elicit smaller P200 in patients (d = -0.36; 95% CI [-0.26, -0.08]); target stimuli elicit larger P200 in patients (d = 0.48; 95% CI [0.16, 0.82]). A similar effect occurs for latency at Cz, which is shorter for standards (d = -0.32; 95% CI [-0.54, -0.10]) and longer for targets (d = 0.42; 95% CI [0.23, 0.62]). Meta-regression analyses revealed that samples with more males show larger ES for amplitude of target stimuli, while the amount of medication was negatively associated with the ES for the latency of standards.

CONCLUSIONS

The results obtained suggest that claims of reduced or augmented P200 in schizophrenia based on the sole examination of standard or target stimuli fail to consider the stimulus effect.

SIGNIFICANCE

Quantification of effects for standard and target stimuli is a required first step to understand the nature of P200 deficits in schizophrenia.

E-cadherin immunoexpression patterns in the characterisation of gastric carcinoma histotypes

AIMS

E-cadherin, the main epithelial intercellular adhesion molecule, is abnormally expressed in many cancer types, including gastric carcinoma, which is the second leading cause of cancer death worldwide. The aim of this study was to contribute to the characterisation of gastric carcinoma histotypes based on a new approach to E-cadherin immunoexpression.

METHODS

97 gastric tumour samples obtained from the files of the Hospital of Cancer/Cancer Institute of Ceará, Brazil, were histologically analysed and classified as intestinal (n=40), diffuse (n=34), mixed (n=16) or unclassified (n=7) carcinomas. Immunohistochemistry was performed on the tissue microarray sections. Scores were applied according to the system of Jawhari: 0, no staining; 1, cytoplasmic staining; 2, cytoplasmic and membranous staining in the same case; 3, normal membranous immunoexpression; abnormal patterns: scores 0, 1 and 2; normal pattern: score 3. Jawhari scores were then evaluated utilising another approach: the absence of membranous expression scores (0 and 1) versus the presence of membranous expression (scores 2 and 3).

RESULTS

A significant association between membranous expression of E-cadherin and the intestinal histotype (36/40 (90%), and 28/41 (68%) for other histotypes) was found, while diffuse carcinomas were related to the absence of membranous expression. A very strong and peculiar relationship was observed between cytoplasm-exclusive E-cadherin expression (score 1) and the diffuse component of mixed tumours (11/16 (69%)).

CONCLUSIONS

E-cadherin immunoexpression patterns help us to characterise gastric carcinoma histotypes. The presence or absence of membranous staining is the most valuable criterion in evaluating E-cadherin expression. Mixed tumours show a characteristic E-cadherin cytoplasmic expression in gastric carcinomas.

Accumulation and biological cycling of heavy metal in four salt marsh species, from Tagus estuary (Portugal)

Pools of Zn, Cu, Cd and Co in leaf, stem and root tissues of Sarcocornia fruticosa, Sarcocornia perennis, Halimione portulacoides and Spartina maritima were analyzed on a bimonthly basis, in a Tagus estuary salt marsh. All the major concentrations were found in the root tissues, being the concentrations in the aboveground organs neglectable for sediment budget proposes, as seen by the low root-aboveground translocation. Metal annual accumulation, root turnovers and cycling coefficients were also assessed. S. maritima showed the higher root turnovers and cycling coefficients for most of the analyzed metals, making this a phytostabilizer specie. By contrast the low root turnover, cycling coefficient and low root necromass generation makes S. perennis the most suitable specie for phytoremediation processes. Although the high amounts of metal return to the sediments, due to root senescence, salt marshes can still be considered sinks of heavy metals, cycling heavy metals mostly between sediment and root.

Using Signal Detection Theory Indexes for the Experimental Manipulation of Emotional States

Classic studies regarding emotional processing, either in normal subjects or in pathological groups, rely on the basic assumption of a linear correspondence between stimuli input and perceived emotional information. This neglects the evidence that different experimental groups may perceive the same stimuli features differently. Thus, when emotional input is to act as an independent variable, it becomes fundamental to assure equivalent emotional loading in all groups under comparison, even if using different stimuli. This is not a commonly used procedure when studying emotion or its influence on other cognitive processes. In order to address this issue, a signal detection theory based methodology is presented, which permits measuring sensitivity indices for emotional stimuli, while controlling participants’ subjective criteria. This proposal may represent a useful methodological approach for the study of several emotion-related problems and albeit applicable to any group of subjects.

Evolutionary history of lamprey paired species Lampetra fluviatilis (L.) and Lampetra planeri (Bloch) as inferred from mitochondrial DNA variation

A remarkable trend in the evolution of lampreys is the occurrence in most genera of 'paired species', in which the parasitic anadromous lampreys are believed to have given rise to nonparasitic freshwater resident populations. The present work examines the phylogeography of the European paired species Lampetra fluviatilis and Lampetra planeri, in an attempt to elucidate species pair evolutionary history. We studied sequence variation in cytochrome b and ATPase 6, 8 mitochondrial genes in 63 individuals from 21 localities of the paired species throughout their distribution range. Results from the phylogenetic and nested clade analyses were largely consistent, suggesting the existence of three major evolutionary lineages: lineage I and possibly lineage II are widespread throughout Europe, while the most ancestral lineage III is apparently restricted to the Iberian Peninsula. The high genetic diversity observed in the Iberian Peninsula is probably the result of refugial persistence and subsequent accumulation of variation over several ice ages, whereas the low levels of genetic diversity observed in central and northern Europe should reflect a rapid postglacial colonization. Results suggest that L. planeri originated within at least two distinct evolutionary lineages, rejecting the single origin hypothesis. The observed lack of taxa monophyly within lineage I may be the result of ongoing gene flow if the two taxa are alternate life-history forms of a single species. However, structure within lineage I is also consistent with the hypothesis of divergence of taxa after postglacial dispersion (around 2000 generations ago) with incomplete lineage sorting. Further testing of the alternative hypotheses is warranted.