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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.
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Ácidos Grasos , Agua Dulce , Smegmamorpha , Animales , Smegmamorpha/metabolismo , Femenino , Ácidos Grasos/metabolismo , Migración Animal/fisiología , Gónadas/metabolismo , Músculos/metabolismoRESUMEN
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.
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Trastorno de Personalidad Antisocial , Variación Contingente Negativa , HumanosRESUMEN
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.
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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.
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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.
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The psychopathic traits boldness, meanness, and disinhibition are theorized to be underlined by trait fearlessness and externalizing vulnerability as etiologic neurobiological processes. However, little is known about the neurophysiological correlates of these traits. In this work, we explored how the three traits are associated with event-related potential (ERP) components targeted at the etiological processes in a partial delayed threat conditioning task and in a go/no-go task. Fifty community-dwelling volunteers (25 women), without history of neurological or psychiatric conditions, were recruited and assessed for psychopathic traits using the triarchic psychopathy measure. Participants performed a threat conditioning task, and a go/no-go task while undergoing an electroencephalography recording. Results from the threat conditioning task showed that boldness was significantly associated with reduced late positive potential. Concerning the go/no-go task, disinhibition was significantly associated with reduced error-related negativity ERP component. Overall, distinct psychopathic traits were found to be associated with distinct neurophysiological correlates of threat conditioning and response inhibition. This is consistent with models of psychopathy entailing trait fearlessness and externalizing proneness, and related brain mechanisms, as distinct processes underlying the expression of psychopathic traits.
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Trastorno de Personalidad Antisocial/fisiopatología , Condicionamiento Clásico/fisiología , Potenciales Evocados/fisiología , Miedo/fisiología , Inhibición Psicológica , Pruebas Neuropsicológicas , Desempeño Psicomotor/fisiología , Adolescente , Adulto , Electroencefalografía , Potenciales Relacionados con Evento P300/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Adulto JovenRESUMEN
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).
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Trastorno de Personalidad Antisocial/diagnóstico , Prisioneros/psicología , Adolescente , Adulto , Anciano , Trastorno de Personalidad Antisocial/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Psicológicos , Portugal , Escalas de Valoración Psiquiátrica , Psicometría , Curva ROC , Reproducibilidad de los Resultados , Traducciones , Adulto JovenRESUMEN
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.
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Fotopletismografía/instrumentación , Psicofisiología/instrumentación , Tecnología Inalámbrica/instrumentación , Adulto , Algoritmos , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Masculino , Reproducibilidad de los Resultados , Procesamiento de Señales Asistido por Computador/instrumentaciónRESUMEN
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.
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Peces/fisiología , Oocitos/crecimiento & desarrollo , Oogénesis , Animales , Femenino , Fertilidad , Portugal , RíosRESUMEN
With respect to De Dreu and Gross's article, we comment on the psychological functions for attack and defense, focusing on associations between individual differences in psychopathic personality traits and the behavioral patterns observed in attack-defense conflicts. We highlight the dimensional nature of psychopathy and formulate hypothetical associations between distinct traits, their different behavioral outcomes, and associated brain mechanisms.
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Trastorno de Personalidad Antisocial , Encéfalo , Cognición , HumanosRESUMEN
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 ß-oxidation, such as C18:1ω9 but also by medium chain FA and PUFA which points that PUFA are spared as fuel to ß-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.
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Metabolismo Energético/fisiología , Ácidos Grasos/metabolismo , Músculo Esquelético/metabolismo , Petromyzon/metabolismo , Animales , Biomarcadores , Cromatografía de Gases y Espectrometría de Masas , Larva/crecimiento & desarrollo , Larva/metabolismo , Petromyzon/crecimiento & desarrolloRESUMEN
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.
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Evolución Biológica , Ecosistema , Modelos Biológicos , Análisis Numérico Asistido por Computador , Saccharomyces cerevisiae/metabolismo , Factores de TiempoRESUMEN
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 JacketTM 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.
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Electrocardiografía , Frecuencia Cardíaca , Monitoreo Fisiológico/métodos , Estrés Fisiológico , Prueba de Esfuerzo , HumanosRESUMEN
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.
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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.
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Trastorno de Personalidad Antisocial/diagnóstico , Nivel de Alerta/fisiología , Criminales/psicología , Emociones/fisiología , Prisioneros , Detección de Señal Psicológica , Adulto , Afecto/fisiología , Trastorno de Personalidad Antisocial/psicología , Estudios de Casos y Controles , Señales (Psicología) , Humanos , Masculino , Modelos Psicológicos , Reconocimiento Visual de Modelos , Prisioneros/psicología , Prisioneros/estadística & datos numéricos , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Sensibilidad y Especificidad , Adulto JovenRESUMEN
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.
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Estimulación Acústica/métodos , Electroencefalografía/métodos , Potenciales Evocados Auditivos/fisiología , Sonido , Adulto , Femenino , Humanos , Masculino , Tiempo de Reacción/fisiología , Adulto JovenRESUMEN
Findings concerning the emotional modulation of the N170 component of the visual event-related potential are mixed. In the present report we tested the hypothesis that the emotional modulation of the N170 may be driven by the perceived emotional arousal of the stimuli, rather than by specific emotional categories. Fifty-four participants viewed facial expressions of anger, disgust, fear and happiness, plus low arousal neutral faces. All emotional categories were matched in arousal, while stimuli within each category varied parametrically in this dimension. The modulation of the electrocortical activity on the N170 time-window was analyzed in the time domain and via time-frequency decomposition. The effects of emotion and arousal were analyzed separately. In the time domain N170 amplitudes co-varied parametrically with perceived arousal, regardless of emotional category. This modulation was linearly associated with the power of the theta, alpha, and beta frequency bands. Moreover, fear was associated with a trend for increased N170 amplitudes, enhanced alpha power, and increased broad band inter-trial phase coherence. These results support the views that a) the activity in N170 time window is fundamentally modulated by perceived arousal, b) the modulation of the N170 may be the product of an increased evoked response, rather than the result of phase resetting processes, and c) facial expressions of fear retain some processing primacy, that may be related to their increased value as environmental cues.
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Nivel de Alerta/fisiología , Emociones/fisiología , Potenciales Evocados Visuales/fisiología , Expresión Facial , Estimulación Luminosa/métodos , Percepción Visual/fisiología , Adulto , Femenino , Humanos , Masculino , Factores de Tiempo , Adulto JovenRESUMEN
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.
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Trastorno de Personalidad Antisocial/patología , Corteza Cerebral/patología , Adolescente , Envejecimiento/patología , Envejecimiento/psicología , Amígdala del Cerebelo/patología , Trastorno de Personalidad Antisocial/psicología , Femenino , Sustancia Gris/patología , Humanos , Pruebas de Inteligencia , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Personalidad , Putamen/patología , Conducta Social , Adulto JovenRESUMEN
The N1 and P2 components of the event-related potential are relevant markers in the processing of auditory information, indicating the presence of several acoustic phenomena, such as pure tones or speech sounds. In addition, the expression of these components seems to be sensitive to diverse experimental variations. The main purpose of the present investigation was to explore the role of inter-stimulus interval (ISI) on the N1 and P2 responses, considering two widely used experimental paradigms: a single tone task (1000 Hz sound repeated in a fixed rhythm) and an auditory oddball (80% of the stimuli were equal to the sound used in the single tone and the remaining were a 1500 Hz tone). Both tasks had four different conditions, and each one tested a fixed value of ISI (600, 1000, 3000, or 6000 ms). A sample of 22 participants performed these tasks, while an EEG was recorded, in order to examine the maximum amplitude of the N1 and P2 components. Analysis of the stimuli in the single tone task and the frequent tones in the oddball task revealed a similar outcome for both tasks and for both components: N1 and P2 amplitudes were enhanced in conditions with longer ISIs regardless of task. This response pattern emphasizes the dependence of both the N1 and P2 components on the ISI, especially in a scenario of repetitive and regular stimulation. The absence of task effects suggests that the ISI effect reported may depend on refractory mechanisms rather than being due to habituation effects.
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Estimulación Acústica/métodos , Potenciales Evocados Auditivos/fisiología , Desempeño Psicomotor/fisiología , Tiempo de Reacción/fisiología , Adulto , Potenciales Evocados/fisiología , Femenino , Humanos , Masculino , Factores de Tiempo , Adulto JovenRESUMEN
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.