Individual Differences in Working Memory Capacity Modulate Electrophysiological Correlates of Semantic Negative Priming From Single Words.

In the present study, event-related potentials (ERPs) were registered during a semantic negative priming (NP) task in participants with higher and lower working memory capacity (WMC). On each trial participants had to actively ignore a briefly presented single prime word, which was followed either immediately or after a delay by a mask. Thereafter, either a semantically related or an unrelated target word was presented, to which participants made a semantic categorization judgment. The ignored prime produced a behavioral semantic NP in delayed (but not in immediate) masking trials, and only for participants with a higher-WMC. Both masking type and WMC also modulated ERP priming effects. When the ignored prime was immediately followed by a mask (which impeded its conscious identification) a reliable N400 modulation was found irrespective of participants' WMC. However, when the mask onset following the prime was delayed (thus allowing its conscious identification), an attenuation of a late positive ERP (LPC) was observed in related compared to unrelated trials, but only in the higher-WMC group showing reliable behavioral NP. The present findings demonstrate for the first time that individual differences in WMC modulate both behavioral measures and electrophysiological correlates of semantic NP.

Semantic Negative Priming From an Ignored Single-Prime Depends Critically on Prime-Mask Inter-Stimulus Interval and Working Memory Capacity.

The aim of this study is to examine the link between working memory capacity and the ability to exert cognitive control. Here, participants with either high or low working memory capacity (WMC) performed a semantic negative priming (NP) task as a measure of cognitive control. They were required to ignore a single prime word followed by a pattern mask appearing immediately or after a delay. The prime could be semantically related or unrelated to an upcoming target word where a forced-choice categorization was required. Each type of mask (immediate vs. delayed) appeared randomly from trial to trial. Results demonstrated that, when the ignored prime was immediately followed by the mask, neither of the groups (high or low WMC) showed reliable NP. In clear contrast, when the mask onset was delayed responses latencies were reliably slower for semantically related trials than for unrelated trials (semantic NP), but only for the high WMC group. The present results clearly demonstrate that semantic NP from single ignored primes depends on both the masking pattern that follows the prime (immediate vs. delayed mask), and on working memory capacity.

The semantic origin of unconscious priming: Behavioral and event-related potential evidence during category congruency priming from strongly and weakly related masked words.

The mechanisms underlying masked congruency priming, semantic mechanisms such as semantic activation or non-semantic mechanisms, for example response activation, remain a matter of debate. In order to decide between these alternatives, reaction times (RTs) and event-related potentials (ERPs) were recorded in the present study, while participants performed a semantic categorization task on visible word targets that were preceded either 167 ms (Experiment 1) or 34 ms before (Experiment 2) by briefly presented (33 ms) novel (unpracticed) masked prime words. The primes and targets belonged to different categories (unrelated), or they were either strongly or weakly semantically related category co-exemplars. Behavioral (RT) and electrophysiological masked congruency priming effects were significantly greater for strongly related pairs than for weakly related pairs, indicating a semantic origin of effects. Priming in the latter condition was not statistically reliable. Furthermore, priming effects modulated the N400 event-related potential (ERP) component, an electrophysiological index of semantic processing, but not ERPs in the time range of the N200 component, associated with response conflict and visuo-motor response priming. The present results demonstrate that masked congruency priming from novel prime words also depends on semantic processing of the primes and is not exclusively driven by non-semantic mechanisms such as response activation.

Evaluación neuropsicológica de procesos cognitivos en niños de siete años de edad nacidos pretérmino / Neuropsychological assessment of cognitive processes in seven-yearold children born prematurely

Introducción. Diversas investigaciones han demostrado que el desarrollo cognitivo de los niños prematuros suele verse afectado, existiendo una estrecha relación entre prematuridad, déficits ejecutivos, trastornos del aprendizaje, alteraciones del lenguaje y problemas conductuales. Asimismo, destacan también las dificultades en tareas viso-perceptivas y de integración funcional. Objetivo. Evaluar los procesos cognitivos (funciones ejecutivas, integración viso-perceptiva, coordinación viso-motora, memoria, conocimiento del medio, lenguaje, procesamiento visomotor y aptitud motora) en niños de siete años de edad nacidos pretérmino y compararlos con un grupo control, igualado en las variables nivel sociocultural, sexo y edad. Sujetos y método. Participaron 20 niños con edades comprendidas entre siete años y dos meses y siete años y 11 meses, distribuidos homogéneamente en dos grupos (prematuro vs. control). Se elaboró un protocolo de pruebas neuropsicológicas estandarizadas para evaluar los diferentes dominios cognitivos mencionados. Resultados. Los datos obtenidos evidencian una peor ejecución en los niños prematuros en diversos dominios evaluados (v.g., funciones ejecutivas y procesamiento visomotor) en comparación con los controles. Conclusiones. Debido al escaso número de trabajos que analizan procesos cognitivos en niños nacidos pretérmino de habla hispana, en esta investigación se seleccionó la ventana de edad de 7 años, momento en el que se inician procesos esenciales -lectura, escritura y cálculo matemático-, para detectar problemas neuropsicológicos que pudiesen estar influyendo en los procesos académicos, aportando de este modo nuevos hallazgos para el ámbito de la neuropsicología infantil

Introduction. Several studies have shown that the cognitive development of premature children is affected. In fact, it appears to be a close relationship between prematurity, executive deficits, learning disorders, language disorders and behavioral problems. Premature children present also difficulties in viso-perceptive tasks and functional integration tasks. Objective. The main goal of this study was to assess cognitive processes (executive functions, viso-perceptual integration, viso-motor coordination, memory, environmental knowledge, language, viso-motor processing and motor skills) in seven-year-old children who were born preterm and to compare them with those of a control group, matching in sociocultural level, sex and age. Subjects and method. 20 children ranging in age between seven years and two months and seven years and 11 months, assigned to two groups (premature vs. control) participated in the present study. A protocol including standardized neuropsychological tests was designed to assess the different cognitive mentioned domains. Results. We observed that there was worse performance in several evaluated domains (v.g., executive functions and viso-motor processing) in premature children than in the control group. Conclusions. There are few studies that explore cognitive processes in hispanic-speaking children born prematurely. In the present study we selected the seven-year age window, a time in life in which essential processes begin –reading, writing and mathematical calculation-. To detect neuropsychological problems that might be influencing the academic achievement of this population, adding new findings to the field of child neuropsychology