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1.
Cell ; 179(6): 1424-1435.e8, 2019 11 27.
Artículo en Inglés | MEDLINE | ID: mdl-31761530

RESUMEN

The increasing proportion of variance in human complex traits explained by polygenic scores, along with progress in preimplantation genetic diagnosis, suggests the possibility of screening embryos for traits such as height or cognitive ability. However, the expected outcomes of embryo screening are unclear, which undermines discussion of associated ethical concerns. Here, we use theory, simulations, and real data to evaluate the potential gain of embryo screening, defined as the difference in trait value between the top-scoring embryo and the average embryo. The gain increases very slowly with the number of embryos but more rapidly with the variance explained by the score. Given current technology, the average gain due to screening would be ≈2.5 cm for height and ≈2.5 IQ points for cognitive ability. These mean values are accompanied by wide prediction intervals, and indeed, in large nuclear families, the majority of children top-scoring for height are not the tallest.


Asunto(s)
Embrión de Mamíferos/metabolismo , Pruebas Genéticas , Herencia Multifactorial/genética , Adulto , Familia , Estudio de Asociación del Genoma Completo , Humanos , Fenotipo
2.
Artículo en Inglés | MEDLINE | ID: mdl-38296844

RESUMEN

PURPOSE: This study systematically searched for differential correlates of criticism vs. emotional overinvolvement (EOI) towards patients with schizophrenia in families and halfway houses, which have only incidentally been reported in previous research. Identified patterns were compared across settings. METHODS: We included 40 inpatients with schizophrenia living in halfway houses and 40 outpatients living with their families and recorded the expressed emotion (EE) of 22 psychiatric nurses or 56 parents, respectively, through Five Minutes Speech Samples. Each nurse rated 1-12 inpatients and each inpatient was rated by 2-5 nurses. Each outpatient was rated by one or both parents. As EE ratings had a multilevel structure, weighted Spearman correlations of criticism and EOI with various patient- and caregiver-related characteristics were calculated and compared with Meng's z-test. RESULTS: Criticism was weakly negatively correlated with EOI in nurses but negligibly in parents. Distinct patterns of significant differential correlates arose across settings. Outpatients' aggressive behavior and parents' related burden were mainly associated with higher criticism. Inpatients' symptoms (agitation/aggression, negative and other psychotic symptoms) and nurses' burnout (Depersonalization) were mainly associated with lower EOI. Inpatients' perceived criticism and outpatients' previous suicide attempts were equally associated with higher criticism and lower EOI (mirror correlations). Finally, various inpatient attributes (older age, chronicity, unemployment and smoking) triggered higher EOI only. Inpatients' age, psychopathology (esp. agitation/aggression and negative symptoms) and perceived criticism survived adjustment for multiple comparisons. CONCLUSION: Our findings suggest setting-specific pathogenetic pathways of criticism and EOI and might help customize psychoeducational interventions to staff and families.

3.
Behav Res Methods ; 2023 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-37507649

RESUMEN

A guideline is proposed that comprises the minimum items to be reported in research studies involving an eye tracker and human or non-human primate participant(s). This guideline was developed over a 3-year period using a consensus-based process via an open invitation to the international eye tracking community. This guideline will be reviewed at maximum intervals of 4 years.

4.
Am J Hum Genet ; 105(2): 334-350, 2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31374203

RESUMEN

Susceptibility to schizophrenia is inversely correlated with general cognitive ability at both the phenotypic and the genetic level. Paradoxically, a modest but consistent positive genetic correlation has been reported between schizophrenia and educational attainment, despite the strong positive genetic correlation between cognitive ability and educational attainment. Here we leverage published genome-wide association studies (GWASs) in cognitive ability, education, and schizophrenia to parse biological mechanisms underlying these results. Association analysis based on subsets (ASSET), a pleiotropic meta-analytic technique, allowed jointly associated loci to be identified and characterized. Specifically, we identified subsets of variants associated in the expected ("concordant") direction across all three phenotypes (i.e., greater risk for schizophrenia, lower cognitive ability, and lower educational attainment); these were contrasted with variants that demonstrated the counterintuitive ("discordant") relationship between education and schizophrenia (i.e., greater risk for schizophrenia and higher educational attainment). ASSET analysis revealed 235 independent loci associated with cognitive ability, education, and/or schizophrenia at p < 5 × 10-8. Pleiotropic analysis successfully identified more than 100 loci that were not significant in the input GWASs. Many of these have been validated by larger, more recent single-phenotype GWASs. Leveraging the joint genetic correlations of cognitive ability, education, and schizophrenia, we were able to dissociate two distinct biological mechanisms-early neurodevelopmental pathways that characterize concordant allelic variation and adulthood synaptic pruning pathways-that were linked to the paradoxical positive genetic association between education and schizophrenia. Furthermore, genetic correlation analyses revealed that these mechanisms contribute not only to the etiopathogenesis of schizophrenia but also to the broader biological dimensions implicated in both general health outcomes and psychiatric illness.


Asunto(s)
Trastornos del Conocimiento/fisiopatología , Cognición/fisiología , Escolaridad , Trastornos del Neurodesarrollo/etiología , Polimorfismo de Nucleótido Simple , Esquizofrenia/fisiopatología , Transmisión Sináptica , Adulto , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Humanos , Trastornos del Neurodesarrollo/patología
5.
CNS Spectr ; 27(6): 716-723, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-34369340

RESUMEN

BACKGROUND: The aim of the current study was to explore the effect of gender, age at onset, and duration on the long-term course of schizophrenia. METHODS: Twenty-nine centers from 25 countries representing all continents participated in the study that included 2358 patients aged 37.21 ± 11.87 years with a DSM-IV or DSM-5 diagnosis of schizophrenia; the Positive and Negative Syndrome Scale as well as relevant clinicodemographic data were gathered. Analysis of variance and analysis of covariance were used, and the methodology corrected for the presence of potentially confounding effects. RESULTS: There was a 3-year later age at onset for females (P < .001) and lower rates of negative symptoms (P < .01) and higher depression/anxiety measures (P < .05) at some stages. The age at onset manifested a distribution with a single peak for both genders with a tendency of patients with younger onset having slower advancement through illness stages (P = .001). No significant effects were found concerning duration of illness. DISCUSSION: Our results confirmed a later onset and a possibly more benign course and outcome in females. Age at onset manifested a single peak in both genders, and surprisingly, earlier onset was related to a slower progression of the illness. No effect of duration has been detected. These results are partially in accord with the literature, but they also differ as a consequence of the different starting point of our methodology (a novel staging model), which in our opinion precluded the impact of confounding effects. Future research should focus on the therapeutic policy and implications of these results in more representative samples.


Asunto(s)
Esquizofrenia , Humanos , Femenino , Masculino , Esquizofrenia/diagnóstico , Esquizofrenia/epidemiología , Edad de Inicio , Manual Diagnóstico y Estadístico de los Trastornos Mentales
6.
Postgrad Med J ; 98(1159): 321-327, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-33782202

RESUMEN

COVID-19 pandemic has undoubtedly disrupted the well-established, traditional structure of medical education. Τhe new limitations of physical presence have accelerated the development of an online learning environment, comprising both of asynchronous and synchronous distance education, and the introduction of novel ways of student assessment. At the same time, this prolonged crisis had serious implications on the lives of medical students including their psychological well-being and the impact on their academic trajectories. The new reality has, on many occasions, triggered the 'acting up' of medical students as frontline healthcare staff, which has been perceived by many of them as a positive learning and contributing experience, and has led to a variety of responses from the educational institutions. All things considered, the urgency for rapid and novel adaptations to the new circumstances has functioned as a springboard for remarkable innovations in medical education,including the promotion of a more "evidence-based" approach.


Asunto(s)
COVID-19 , Educación a Distancia , Educación Médica , Estudiantes de Medicina , COVID-19/epidemiología , Humanos , Pandemias , SARS-CoV-2
7.
Eur Child Adolesc Psychiatry ; 31(8): 1-18, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-33751240

RESUMEN

Disorders with neurodevelopmental aetiology such as Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD) and Schizophrenia share commonalities at many levels of investigation despite phenotypic differences. Evidence of genetic overlap has led to the concept of a continuum of neurodevelopmental impairment along which these disorders can be positioned in aetiological, pathophysiological and developmental features. This concept requires their simultaneous comparison at different levels, which has not been accomplished so far. Given that cognitive impairments are core to the pathophysiology of these disorders, we provide for the first time differentiated head-to-head comparisons in a complex cognitive function, visual search, decomposing the task with eye movement-based process analyses. N = 103 late-adolescents with schizophrenia, ADHD, ASD and healthy controls took a serial visual search task, while their eye movements were recorded. Patients with schizophrenia presented the greatest level of impairment across different phases of search, followed by patients with ADHD, who shared with patients with schizophrenia elevated intra-subject variability in the pre-search stage. ASD was the least impaired group, but similar to schizophrenia in post-search processes and to schizophrenia and ADHD in pre-search processes and fixation duration while scanning the items. Importantly, the profiles of deviancy from controls were highly correlated between all three clinical groups, in line with the continuum idea. Findings suggest the existence of one common neurodevelopmental continuum of performance for the three disorders, while quantitative differences appear in the level of impairment. Given the relevance of cognitive impairments in these three disorders, we argue in favour of overlapping pathophysiological mechanisms.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad , Trastorno del Espectro Autista , Disfunción Cognitiva , Esquizofrenia , Adolescente , Trastorno por Déficit de Atención con Hiperactividad/psicología , Trastorno del Espectro Autista/psicología , Cognición , Humanos
8.
Sensors (Basel) ; 22(19)2022 Oct 05.
Artículo en Inglés | MEDLINE | ID: mdl-36236643

RESUMEN

Wearable technologies and digital phenotyping foster unique opportunities for designing novel intelligent electronic services that can address various well-being issues in patients with mental disorders (i.e., schizophrenia and bipolar disorder), thus having the potential to revolutionize psychiatry and its clinical practice. In this paper, we present e-Prevention, an innovative integrated system for medical support that facilitates effective monitoring and relapse prevention in patients with mental disorders. The technologies offered through e-Prevention include: (i) long-term continuous recording of biometric and behavioral indices through a smartwatch; (ii) video recordings of patients while being interviewed by a clinician, using a tablet; (iii) automatic and systematic storage of these data in a dedicated Cloud server and; (iv) the ability of relapse detection and prediction. This paper focuses on the description of the e-Prevention system and the methodologies developed for the identification of feature representations that correlate with and can predict psychopathology and relapses in patients with mental disorders. Specifically, we tackle the problem of relapse detection and prediction using Machine and Deep Learning techniques on all collected data. The results are promising, indicating that such predictions could be made and leading eventually to the prediction of psychopathology and the prevention of relapses.


Asunto(s)
Trastornos Psicóticos , Esquizofrenia , Dispositivos Electrónicos Vestibles , Humanos , Trastornos Psicóticos/diagnóstico , Trastornos Psicóticos/prevención & control , Recurrencia , Prevención Secundaria
9.
CNS Spectr ; 26(3): 290-298, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-32290897

RESUMEN

BACKGROUND: The aim of the current study was to explore the changing interrelationships among clinical variables through the stages of schizophrenia in order to assemble a comprehensive and meaningful disease model. METHODS: Twenty-nine centers from 25 countries participated and included 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Multiple linear regression analysis and visual inspection of plots were performed. RESULTS: The results suggest that with progression stages, there are changing correlations among Positive and Negative Syndrome Scale factors at each stage and each factor correlates with all the others in that particular stage, in which this factor is dominant. This internal structure further supports the validity of an already proposed four stages model, with positive symptoms dominating the first stage, excitement/hostility the second, depression the third, and neurocognitive decline the last stage. CONCLUSIONS: The current study investigated the mental organization and functioning in patients with schizophrenia in relation to different stages of illness progression. It revealed two distinct "cores" of schizophrenia, the "Positive" and the "Negative," while neurocognitive decline escalates during the later stages. Future research should focus on the therapeutic implications of such a model. Stopping the progress of the illness could demand to stop the succession of stages. This could be achieved not only by both halting the triggering effect of positive and negative symptoms, but also by stopping the sensitization effect on the neural pathways responsible for the development of hostility, excitement, anxiety, and depression as well as the deleterious effect on neural networks responsible for neurocognition.


Asunto(s)
Esquizofrenia/diagnóstico , Psicología del Esquizofrénico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Progresión de la Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad
10.
Eur J Clin Invest ; 50(3): e13208, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31995842

RESUMEN

BACKGROUND: Patients with body dysmorphic disorder (BDD) exhibit differential attentional mechanisms compared to healthy subjects. The exact nature of this differentiation is unclear. To this end, EEG (electrophysiological) responses to prepulse inhibition (PPI: reflecting attentional modulation) and prepulse facilitation (PPF: indicating orienting activation) were recorded and analysed. The aim of this study was to compare the respective neural oscillations associated with PPI and PPF in BDD vs healthy controls. MATERIALS AND METHODS: Event-related EEG oscillations elicited by PPI and PPF (26 and 25 trials, respectively, randomly presented) were explored in a sample of patients with BDD (N = 30) vs healthy controls (N = 25). The Yale-Brown Obsessive-Compulsive Scale for BDD (BDD-YBOCS), the Body Dysmorphic Disorder Examination, the Dysmorphic Concern Questionnaire (DCQ) and the Brown Assessment of Belief Scale (BABS) were also administered. RESULTS: Analysis of the power spectrum in response to PPI and PPF revealed that the BDD patient group compared to healthy controls exhibited higher theta-1 oscillations (potentially indicative of disrupted thalamo-cortical activation) and reduced beta-1 oscillations (potentially indicative of reduced top-down-controlled processing during attentional orienting). CONCLUSION: These findings offer novel contributions with regards to the neural mechanisms underlying attention processes in BDD patients, and demonstrate the potential of event-related EEG oscillations as a tool to better understand body dysmorphic disorder.


Asunto(s)
Trastorno Dismórfico Corporal/fisiopatología , Adulto , Electroencefalografía , Femenino , Humanos , Masculino , Adulto Joven
11.
Int J Neuropsychopharmacol ; 22(11): 681-697, 2019 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-31563956

RESUMEN

INTRODUCTION: A specific clinically relevant staging model for schizophrenia has not yet been developed. The aim of the current study was to evaluate the factor structure of the PANSS and develop such a staging method. METHODS: Twenty-nine centers from 25 countries contributed 2358 patients aged 37.21 ± 11.87 years with schizophrenia. Analysis of covariance, Exploratory Factor Analysis, Discriminant Function Analysis, and inspection of resultant plots were performed. RESULTS: Exploratory Factor Analysis returned 5 factors explaining 59% of the variance (positive, negative, excitement/hostility, depression/anxiety, and neurocognition). The staging model included 4 main stages with substages that were predominantly characterized by a single domain of symptoms (stage 1: positive; stages 2a and 2b: excitement/hostility; stage 3a and 3b: depression/anxiety; stage 4a and 4b: neurocognition). There were no differences between sexes. The Discriminant Function Analysis developed an algorithm that correctly classified >85% of patients. DISCUSSION: This study elaborates a 5-factor solution and a clinical staging method for patients with schizophrenia. It is the largest study to address these issues among patients who are more likely to remain affiliated with mental health services for prolonged periods of time.


Asunto(s)
Progresión de la Enfermedad , Escalas de Valoración Psiquiátrica/estadística & datos numéricos , Esquizofrenia/diagnóstico , Adulto , Europa (Continente) , Análisis Factorial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nigeria , Esquizofrenia/clasificación , Esquizofrenia/fisiopatología , Síndrome de Sotos , Adulto Joven
14.
Twin Res Hum Genet ; 21(5): 394-397, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30001766

RESUMEN

Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84-88) presented a critique of our recently published paper in Cell Reports entitled 'Large-Scale Cognitive GWAS Meta-Analysis Reveals Tissue-Specific Neural Expression and Potential Nootropic Drug Targets' (Lam et al., Cell Reports, Vol. 21, 2017, 2597-2613). Specifically, Hill offered several interrelated comments suggesting potential problems with our use of a new analytic method called Multi-Trait Analysis of GWAS (MTAG) (Turley et al., Nature Genetics, Vol. 50, 2018, 229-237). In this brief article, we respond to each of these concerns. Using empirical data, we conclude that our MTAG results do not suffer from 'inflation in the FDR [false discovery rate]', as suggested by Hill (Twin Research and Human Genetics, Vol. 21, 2018, 84-88), and are not 'more relevant to the genetic contributions to education than they are to the genetic contributions to intelligence'.


Asunto(s)
Estudio de Asociación del Genoma Completo , Nootrópicos , Cognición , Predisposición Genética a la Enfermedad , Humanos , Polimorfismo de Nucleótido Simple
15.
Neuroimage ; 128: 328-341, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26806289

RESUMEN

In this study predictions of the dual-route cascaded (DRC) model of word reading were tested using fMRI. Specifically, patterns of co-localization were investigated: (a) between pseudoword length effects and a pseudowords vs. fixation contrast, to reveal the sublexical grapho-phonemic conversion (GPC) system; and (b) between word frequency effects and a words vs. pseudowords contrast, to reveal the orthographic and phonological lexicon. Forty four native speakers of Greek were scanned at 3T in an event-related lexical decision task with three event types: (a) 150 words in which frequency, length, bigram and syllable frequency, neighborhood, and orthographic consistency were decorrelated; (b) 150 matched pseudowords; and (c) fixation. Whole-brain analysis failed to reveal the predicted co-localizations. Further analysis with participant-specific regions of interest defined within masks from the group contrasts revealed length effects in left inferior parietal cortex and frequency effects in the left middle temporal gyrus. These findings could be interpreted as partially consistent with the existence of the GPC system and phonological lexicon of the model, respectively. However, there was no evidence in support of an orthographic lexicon, weakening overall support for the model. The results are discussed with respect to the prospect of using neuroimaging in cognitive model evaluation.


Asunto(s)
Encéfalo/fisiología , Reconocimiento Visual de Modelos/fisiología , Lectura , Adulto , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Reconocimiento en Psicología/fisiología , Adulto Joven
16.
Brain Cogn ; 107: 37-47, 2016 08.
Artículo en Inglés | MEDLINE | ID: mdl-27363008

RESUMEN

The antisaccade task is a prominent tool to investigate the response inhibition component of cognitive control. Recent theoretical accounts explain performance in terms of parallel programming of exogenous and endogenous saccades, linked to the horse race metaphor. Previous studies have tested the hypothesis of competing saccade signals at the behavioral level by selectively slowing the programming of endogenous or exogenous processes e.g. by manipulating the probability of antisaccades in an experimental block. To gain a better understanding of inhibitory control processes in parallel saccade programming, we analyzed task-related eye movements and blood oxygenation level dependent (BOLD) responses obtained using functional magnetic resonance imaging (fMRI) at 3T from 16 healthy participants in a mixed antisaccade and prosaccade task. The frequency of antisaccade trials was manipulated across blocks of high (75%) and low (25%) antisaccade frequency. In blocks with high antisaccade frequency, antisaccade latencies were shorter and error rates lower whilst prosaccade latencies were longer and error rates were higher. At the level of BOLD, activations in the task-related saccade network (left inferior parietal lobe, right inferior parietal sulcus, left precentral gyrus reaching into left middle frontal gyrus and inferior frontal junction) and deactivations in components of the default mode network (bilateral temporal cortex, ventromedial prefrontal cortex) compensated increased cognitive control demands. These findings illustrate context dependent mechanisms underlying the coordination of competing decision signals in volitional gaze control.


Asunto(s)
Corteza Cerebral/fisiología , Función Ejecutiva/fisiología , Movimientos Oculares/fisiología , Inhibición Psicológica , Imagen por Resonancia Magnética , Desempeño Psicomotor/fisiología , Adulto , Animales , Medidas del Movimiento Ocular , Femenino , Humanos , Masculino , Movimientos Sacádicos/fisiología , Adulto Joven
17.
Exp Brain Res ; 233(11): 3097-108, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26226929

RESUMEN

The representation of visual orientation is more accurate for cardinal orientations compared to oblique, and this anisotropy has been hypothesized to reflect a low-level visual process (visual, "class 1" oblique effect). The reproduction of directional and orientation information also leads to a mean error away from cardinal orientations or directions. This anisotropy has been hypothesized to reflect a high-level cognitive process of space categorization (cognitive, "class 2," oblique effect). This space categorization process would be more prominent when the visual representation of orientation degrades such as in the case of working memory with increasing cognitive load, leading to increasing magnitude of the "class 2" oblique effect, while the "class 1" oblique effect would remain unchanged. Two experiments were performed in which an array of orientation stimuli (1-4 items) was presented and then subjects had to realign a probe stimulus within the previously presented array. In the first experiment, the delay between stimulus presentation and probe varied, while in the second experiment, the stimulus presentation time varied. The variable error was larger for oblique compared to cardinal orientations in both experiments reproducing the visual "class 1" oblique effect. The mean error also reproduced the tendency away from cardinal and toward the oblique orientations in both experiments (cognitive "class 2" oblique effect). The accuracy or the reproduced orientation degraded (increasing variable error) and the cognitive "class 2" oblique effect increased with increasing memory load (number of items) in both experiments and presentation time in the second experiment. In contrast, the visual "class 1" oblique effect was not significantly modulated by any one of these experimental factors. These results confirmed the theoretical predictions for the two anisotropies in visual orientation reproduction and provided support for models proposing the categorization of orientation in visual working memory.


Asunto(s)
Cognición/fisiología , Orientación/fisiología , Percepción Visual/fisiología , Adulto , Anisotropía , Femenino , Humanos , Modelos Lineales , Masculino , Memoria a Corto Plazo/fisiología , Estimulación Luminosa , Valor Predictivo de las Pruebas
18.
Am J Med Genet B Neuropsychiatr Genet ; 168B(5): 392-401, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25963331

RESUMEN

Neurocognitive abilities constitute complex traits with considerable heritability. Impaired neurocognition is typically observed in schizophrenia (SZ), whereas convergent evidence has shown shared genetic determinants between neurocognition and SZ. Here, we report a genome-wide association study (GWAS) on neuropsychological and oculomotor traits, linked to SZ, in a general population sample of healthy young males (n = 1079). Follow-up genotyping was performed in an identically phenotyped internal sample (n = 738) and an independent cohort of young males with comparable neuropsychological measures (n = 825). Heritability estimates were determined based on genome-wide single-nucleotide polymorphisms (SNPs) and potential regulatory effects on gene expression were assessed in human brain. Correlations with general cognitive ability and SZ risk polygenic scores were tested utilizing meta-analysis GWAS results by the Cognitive Genomics Consortium (COGENT) and the Psychiatric Genomics Consortium (PGC-SZ). The GWAS results implicated biologically relevant genetic loci encoding protein targets involved in synaptic neurotransmission, although no robust individual replication was detected and thus additional validation is required. Secondary permutation-based analysis revealed an excess of strongly associated loci among GWAS top-ranked signals for verbal working memory (WM) and antisaccade intra-subject reaction time variability (empirical P < 0.001), suggesting multiple true-positive single-SNP associations. Substantial heritability was observed for WM performance. Further, sustained attention/vigilance and WM were suggestively correlated with both COGENT and PGC-SZ derived polygenic scores. Overall, these results imply that common genetic variation explains some of the variability in neurocognitive functioning among young adults, particularly WM, and provide supportive evidence that increased SZ genetic risk predicts neurocognitive fluctuations in the general population.


Asunto(s)
Trastornos del Conocimiento/genética , Predisposición Genética a la Enfermedad , Memoria a Corto Plazo/fisiología , Esquizofrenia/genética , Adolescente , Femenino , Regulación de la Expresión Génica , Estudio de Asociación del Genoma Completo , Genotipo , Humanos , Masculino , Polimorfismo de Nucleótido Simple/genética , Riesgo , Adulto Joven
19.
Exp Brain Res ; 232(7): 2317-24, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24696139

RESUMEN

It is known that visual direction representation is more accurate for cardinal directions compared to oblique, a phenomenon named the "oblique effect". It has been hypothesized that there are two sources of oblique effect, a low level one confined to vision and a high level one extending to different modalities and corresponding to higher cognitive processes. In this study directional error (DE) was measured when normal individuals tried to align the direction of an arrow presented in the center of a computer monitor to the direction of a peripheral target located in one of 32 directions equally spaced on an imaginary circle of 60 mm radius. Task difficulty was manipulated by varying arrow length (15, 30, 45 and 60 mm). By measuring mean DE and its variance we identified two independent sources of the oblique effect. A low level oblique effect was manifested in higher accuracy or equivalently lower variance of DE in the alignment for cardinal orientations compared to oblique. A second oblique effect was manifested measuring mean DE resulting in space expansion in the vicinity of cardinal directions and space contraction in the vicinity of oblique directions. Only this latter source of oblique effect was modulated by arrow length as predicted from a theoretical model postulating that this oblique effect is produced by a cognitive process of 2-D space categorization.


Asunto(s)
Orientación/fisiología , Detección de Señal Psicológica/fisiología , Percepción Espacial/fisiología , Adulto , Análisis de Varianza , Anisotropía , Femenino , Humanos , Masculino , Estimulación Luminosa
20.
Exp Brain Res ; 232(2): 659-73, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24281356

RESUMEN

This study investigated the question whether spatial working memory related to movement plans (motor working memory) and spatial working memory related to spatial attention and perceptual processes (perceptual spatial working memory) share the same neurophysiological substrate or there is evidence for separate motor and perceptual working memory streams of processing. Towards this aim, ten healthy human subjects performed delayed responses to visual targets presented at different spatial locations. Two tasks were attained, one in which the spatial location of the target was the goal for a pointing movement and one in which the spatial location of the target was used for a perceptual (yes or no) change detection. Each task involved two conditions: a memory condition in which the target remained visible only for the first 250 ms of the delay period and a delay condition in which the target location remained visible throughout the delay period. The amplitude spectrum analysis of the EEG revealed that the alpha (8-12 Hz) band signal was smaller, while the beta (13-30 Hz) and gamma (30-45 Hz) band signals were larger in the memory compared to the non-memory condition. The alpha band signal difference was confined to the frontal midline area; the beta band signal difference extended over the right hemisphere and midline central area, and the gamma band signal difference was confined to the right occipitoparietal area. Importantly, both in beta and gamma bands, we observed a significant increase in the movement-related compared to the perceptual-related memory-specific amplitude spectrum signal in the central midline area. This result provides clear evidence for the dissociation of motor and perceptual spatial working memory.


Asunto(s)
Ondas Encefálicas/fisiología , Encéfalo/fisiología , Memoria a Corto Plazo/fisiología , Movimiento/fisiología , Percepción Espacial/fisiología , Adulto , Análisis de Varianza , Mapeo Encefálico , Electroencefalografía , Femenino , Humanos , Masculino , Estimulación Luminosa , Tiempo de Reacción/fisiología , Análisis Espectral
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