"I heard it before or not": time-course of ERP response and behavioural correlates associated with false recognition memory.

Electrophysiological and behavioural correlates of true and false memories were examined in the Deese/Roediger-McDermont (DRM) paradigm. A mass univariate approach for analysing event-related potentials (ERP) in the temporal domain was used to examine the electrophysiological effects associated with this paradigm precisely (point-by-point) and without bias (data-driven). Behaviourally, true and false recognition did not differ, and the predicted DRM effect was observed, as false recognition of critical lures (i.e., new words semantically related to studied words) was higher than false alarms of new (unrelated) words. Neurally, an expected old/new effect was observed during the time-range of the late positive component (LPC) over left centro-parietal scalp electrodes. Furthermore, true recognition also evoked larger LPC amplitudes than false recognition over both left centro-parietal and fronto-central scalp electrodes. However, we did not observe LPC-related differences between critical lures and new words, nor between correct rejections of critical lures and new words. In contrast, correct rejections of critical lures were accompanied by higher activation of a sustained positive slow wave (SPSW) in right fronto-central electrodes beyond 1200 ms. This result reveals a key role of post-retrieval processes in recognition. Results are discussed in light of theoretical approaches to false memory in the DRM paradigm.

El impacto del TDAH sobre la lectura / The impact of ADHD on reading

Resumen Más allá de la frecuente coexistencia del trastorno por déficit de atención con hiperactividad (TDAH) y el trastorno específico del aprendizaje de la lectura, la presente revisión pretende examinar la evidencia empírica disponible sobre cómo el TDAH impacta negativamente sobre el aprendizaje de la lectura. Los datos existentes apuntan a que la presencia del trastorno (especialmente los síntomas de falta de atención), puede afectar a i) la correcta adquisición de lectura, ya sea de manera directa o a través de su influencia sobre los precursores de la lectura; ii) las propias habilidades de decodificación (precisión y fluidez lectora), tanto de manera directa como indirecta a través de su influencia sobre procesos cognitivos como la distracción o las funciones ejecutivas; y ii) la comprensión lectora, probablemente de manera indirecta por las dificultades eje cutivas y en la memoria de trabajo verbal características del TDAH. Estas conclusiones presentan importantes implicaciones para caracterizar e intervenir mejor sobre las dificultades lectoras en el TDAH, ya sean clínicas o subclínicas.

Abstract Beyond the frequent coexistence of attention deficit hyperactivity disorder (ADHD) and reading dis order (dyslexia), the present review aims to examine the available empirical evidence on how ADHD negatively impacts on learning to read. Existing data suggest that the presence of the disorder (especially inattention symp toms), may affect i) the correct acquisition of reading, either directly or through its influence on the precursors to reading; ii) decoding skills themselves (reading accuracy and fluency), both directly and indirectly through its influence on cognitive processes such as distractibility or executive functions; and iii) reading comprehension, probably indirectly through the executive and verbal memory difficulties characteristic of ADHD. These findings have important implications for better characterizing and intervening on reading difficulties in ADHD, whether clinical or subclinical.

[The impact of ADHD on reading]. / El impacto del TDAH sobre la lectura.

Beyond the frequent coexistence of attention deficit hyperactivity disorder (ADHD) and reading disorder (dyslexia), the present review aims to examine the available empirical evidence on how ADHD negatively impacts on learning to read. Existing data suggest that the presence of the disorder (especially inattention symptoms), may affect i) the correct acquisition of reading, either directly or through its influence on the precursors to reading; ii) decoding skills themselves (reading accuracy and fluency), both directly and indirectly through its influence on cognitive processes such as distractibility or executive functions; and iii) reading comprehension, probably indirectly through the executive and verbal memory difficulties characteristic of ADHD. These findings have important implications for better characterizing and intervening on reading difficulties in ADHD, whether clinical or subclinical.

Más allá de la frecuente coexistencia del trastorno por déficit de atención con hiperactividad (TDAH) y el trastorno específico del aprendizaje de la lectura, la presente revisión pretende examinar la evidencia empírica disponible sobre cómo el TDAH impacta negativamente sobre el aprendizaje de la lectura. Los datos existentes apuntan a que la presencia del trastorno (especialmente los síntomas de falta de atención), puede afectar a i) la correcta adquisición de lectura, ya sea de manera directa o a través de su influencia sobre los precursores de la lectura; ii) las propias habilidades de decodificación (precisión y fluidez lectora), tanto de manera directa como indirecta a través de su influencia sobre procesos cognitivos como la distracción o las funciones ejecutivas; y ii) la comprensión lectora, probablemente de manera indirecta por las dificultades ejecutivas y en la memoria de trabajo verbal características del TDAH. Estas conclusiones presentan importantes implicaciones para caracterizar e intervenir mejor sobre las dificultades lectoras en el TDAH, ya sean clínicas o subclínicas.

Déficits neuropsicológicos, intensidad sintomática y repercusión funcional en el trastorno por déficit de atención con hiperactividad / Neuropsychological deficits, symptom intensity and functional impairment in attention deficit hyperactivity disorder

Resumen Este estudio pretende contribuir a una mejor comprensión del trastorno por déficit de atención con hiperactividad (TDAH) examinado de manera exhaustiva la relación entre dos de los principales déficits cognitivos del trastorno (la atención y el control inhibitorio), la sintomatología (falta de atención e hipe ractividad/impulsividad) y la repercusión funcional en 85 niños/as y adolescentes con TDAH sin otros trastornos comórbidos. Encontramos, con independencia del funcionamiento intelectual general y de la edad, que i) un mayor déficit atencional e inhibitorio, predijo una mayor gravedad de los síntomas del TDAH, ii) un mayor déficit atencional e inhibitorio predijo un mayor deterioro funcional, pero no de una manera directa sino a través de los síntomas, y iii) una mayor severidad sintomática predijo una mayor repercusión funcional. Comenzar a explorar y comprender la complejidad del TDAH es clave para avanzar en nuestro conocimiento del trastorno y para la correcta toma de decisiones clínicas.

Abstract This study aims to contribute to a better understanding of at tention deficit hyperactivity disorder (ADHD) by comprehensively examining the relationship between two of the main cognitive deficits of the disorder (attention and inhibitory control), symptomatology (inattention and hyperactivity/impulsivity) and functional impairment in 85 children and adolescents with ADHD without other comorbid disorders. We found, independent of general intellectual functioning and age, that i) greater atten tional and inhibitory deficits predicted greater severity of ADHD symptoms, ii) greater attentional and inhibitory deficits predicted greater functional impairment, but not in a direct way but through symptoms, and iii) greater symptomatic severity predicted greater functional impairment. Beginning to explore and understand the com plexity of ADHD is key to advance our knowledge of the disorder and for correct clinical decision making.

[Neuropsychological deficit, symptom intensity and functional impairment in attention deficit hyperactivity disorder]. / Déficits neuropsicológicos, intensidad sintomática y repercusión funcional en el trastorno por déficit de atención con hiperactividad.

This study aims to contribute to a better understanding of attention deficit hyperactivity disorder (ADHD) by comprehensively examining the relationship between two of the main cognitive deficits of the disorder (attention and inhibitory control), symptomatology (inattention and hyperactivity/impulsivity) and functional impairment in 85 children and adolescents with ADHD without other comorbid disorders. We found, independent of general intellectual functioning and age, that i) greater attentional and inhibitory deficits predicted greater severity of ADHD symptoms, ii) greater attentional and inhibitory deficits predicted greater functional impairment, but not in a direct way but through symptoms, and iii) greater symptomatic severity predicted greater functional impairment. Beginning to explore and understand the complexity of ADHD is key to advance our knowledge of the disorder and for correct clinical decision making.

Este estudio pretende contribuir a una mejor comprensión del trastorno por déficit de atención con hiperactividad (TDAH) examinado de manera exhaustiva la relación entre dos de los principales déficits cognitivos del trastorno (la atención y el control inhibitorio), la sintomatología (falta de atención e hiperactividad / impulsividad) y la repercusión funcional en 85 niños/as y adolescentes con TDAH sin otros trastornos comórbidos. Encontramos, con independencia del funcionamiento intelectual general y de la edad, que i) un mayor déficit atencional e inhibitorio, predijo una mayor gravedad de los síntomas del TDAH, ii) un mayor déficit atencional e inhibitorio predijo un mayor deterioro funcional, pero no de una manera directa sino a través de los síntomas, y iii) una mayor severidad sintomática predijo una mayor repercusión funcional. Comenzar a explorar y comprender la complejidad del TDAH es clave para avanzar en nuestro conocimiento del trastorno y para la correcta toma de decisiones clínicas.

The development of selective stopping: Qualitative and quantitative changes from childhood to early adulthood.

Although progress has been made in elucidating the behavioral and neural development of global stopping across the lifespan, little is known about the development of selective stopping. This more complex form of inhibitory control is required in real-world situations where ongoing responses must be inhibited to certain stimuli but not others, and can be assessed in laboratory settings using a stimulus selective stopping task. Here we used this task to investigate the qualitative and quantitative developmental changes in selective stopping in a large-scale cross-sectional study with three different age groups (children, preadolescents, and young adults). We found that the ability to stop a response selectively to some stimuli (i.e., use a selective strategy) rather than non-selectively to all presented stimuli (i.e., use a global, non-selective strategy) is fully mature by early preadolescence, and remains stable afterwards at least until young adulthood. By contrast, the efficiency or speed of stopping (indexed by a shorter stop-signal reaction time or SSRT) continues to mature throughout adolescence until young adulthood, both for global and selective implementations of stopping. We also provide some preliminary findings regarding which other task variables beyond the strategy and SSRT predicted age group status. Premature responding (an index of "waiting impulsivity") and post-ignore slowing (an index of cognitive control) were among the most relevant predictors in discriminating between developmental age groups. Although present results need to be confirmed and extended in longitudinal studies, they provide new insights into the development of a relevant form of inhibitory control.

Selective Inhibitory Control in Middle Childhood.

The main aim of this study was to investigate the development of selective inhibitory control in middle childhood, a critical period for the maturation of inhibition-related processes. To this end, 64 children aged 6-7 and 56 children aged 10-11 performed a stimulus-selective stop-signal task, which allowed us to estimate not only the efficiency of response inhibition (the stop-signal reaction time or SSRT), but also the strategy adopted by participants to achieve task demands. We found that the adoption of a non-selective (global) strategy characterized by stopping indiscriminately to all stimuli decreased in older children, so that most of them were able to interrupt their ongoing responses selectively at the end of middle childhood. Moreover, compared to younger children, older children were more efficient in their ability to cancel an initiated response (indexed by a shorter SSRT), regardless of which strategy they used. Additionally, we found improvements in other forms of impulsivity, such as the control of premature responding (waiting impulsivity), and attentional-related processes, such as intra-individual variability and distractibility. The present results suggest that middle childhood represents a milestone in the development of crucial aspects of inhibitory control, including selective stopping.

The effects of discrimination on the adoption of different strategies in selective stopping.

Selective stopping is demanded in situations where responses must be suppressed to certain signals, but not others. To explore this type of inhibition, the standard stop-signal task has been modified to include a selective implementation of response inhibition by introducing a new stimulus that participants should ignore. However, a stimulus-selective stop-signal task can be performed following different strategies. Some participants fulfill the selective implementation of the stopping process after discriminating the stop and ignore signals, but some others stop the ongoing response whenever any new stimulus appears. The factors that influence this strategy choice are being explored, where both task and participant variables are under consideration. This study aimed to investigate whether the difficulty in discriminating between stop and ignore signals influences strategy adoption. Additionally, we examined whether participants modify their strategy in a flexible manner throughout the task in alternating easy and hard discrimination condition blocks. In the easy discrimination condition, the stop and the ignore signals differed both in color and shape, whereas in the hard discrimination condition, they only differed in shape. Our results from 64 participants revealed that manipulating the difficulty of signal discrimination strongly influenced strategy choice. Also, we found that participants can adapt their strategy according to task demands. They preferentially adopted a selective stopping strategy when discrimination was easy, whereas they changed to a nonselective stopping strategy under the hard discrimination condition. Overall, results from the current study suggest that signal discrimination difficulty influences the adoption of strategies in selective stopping.

Oscillatory brain mechanisms supporting response cancellation in selective stopping strategies.

Although considerable progress has been made in understanding the neural substrates of simple or global stopping, the neural mechanisms supporting selective stopping remain less understood. The selectivity of the stop process is often required in our everyday life in situations where responses must be suppressed to certain signals but not others. Here, we examined the oscillatory brain mechanisms of response cancellation in selective stopping by controlling for the different strategies adopted by participants (n = 54) to accomplish a stimulus selective stop-signal task. We found that successfully cancelling an initiated response was specifically associated with increased oscillatory activity in the high-beta frequency range in the strategy characterized by stopping selectively (the so called dependent Discriminate then Stop, dDtS), but not in the strategy characterized by stopping non-selectively (Stop then Discriminate, StD). Beamforming source reconstruction suggests that this high-beta activity was mainly generated in the superior frontal gyrus (including the pre-supplementary motor area) and the middle frontal gyrus. Present findings provide neural support for the existence of different strategies for solving selective stopping tasks. Specifically, differences between strategies were observed in the oscillatory activity associated with the stop process and were restricted to the high-beta frequency range. Moreover, current results provide important evidence suggesting that high-beta oscillations in superior and middle frontal cortices play an essential role in cancelling an initiated motor response.

The association of monoamine-related gene polymorphisms with behavioural correlates of response inhibition: A meta-analytic review.

Response inhibition has been shown to be associated with monoamine-related gene polymorphisms, although evidence is inconclusive. To comprehensively examine these genotype effects on behavioural correlates of response inhibition in non-clinical adult populations, we performed a two-step approach. A systematic review of studies using Go/No-Go and/or Stop-Signal paradigms was first carried out. Thirty-eight eligible research articles were identified, which examined over 15 candidate genes. Remarkably, no firm conclusions could be drawn from these studies. Thus, in a second step, we conducted meta-analyses using random effects models on those polymorphisms that had previously been investigated in at least three studies. Specifically, data from 11 studies was analysed in three meta-analyses for the following polymorphisms: SLC6A3 3'UTR VNTR (k=6 samples; n=1463 participants), COMT Val158Met SNP (k=7 samples; n=784) and SLC6A4 5-HTTLPR (k=4 samples, n=204). None of these polymorphisms showed a reliable association with response inhibition performance. The methodological and theoretical implications of these findings are discussed, along with recommendations for future research.

Neural and behavioral correlates of selective stopping: Evidence for a different strategy adoption.

The present study examined the neural and behavioral correlates of selective stopping, a form of inhibition that has scarcely been investigated. The selectivity of the inhibitory process is needed when individuals have to deal with an environment filled with multiple stimuli, some of which require inhibition and some of which do not. The stimulus-selective stop-signal task has been used to explore this issue assuming that all participants interrupt their ongoing responses selectively to stop but not to ignore signals. However, recent behavioral evidence suggests that some individuals do not carry out the task as experimenters expect, since they seemed to interrupt their response non-selectively to both signals. In the present study, we detected and controlled the cognitive strategy adopted by participants (n=57) when they performed a stimulus-selective stop-signal task before comparing brain activation between conditions. In order to determine both the onset and the end of the response cancellation process underlying each strategy and to fully take advantage of the precise temporal resolution of event-related potentials, we used a mass univariate approach. Source localization techniques were also employed to estimate the neural underpinnings of the effects observed at the scalp level. Our results from scalp and source level analysis support the behavioral-based strategy classification. Specific effects were observed depending on the strategy adopted by participants. Thus, when contrasting successful stop versus ignore conditions, increased activation was only evident for subjects who were classified as using a strategy whereby the response interruption process was selective to stop trials. This increased activity was observed during the P3 time window in several left-lateralized brain regions, including middle and inferior frontal gyri, as well as parietal and insular cortices. By contrast, in those participants who used a strategy characterized by stopping non-selectively, no activation differences between successful stop and ignore conditions were observed at the estimated time at which response interruption process occurs. Overall, results from the current study highlight the importance of controlling for the different strategies adopted by participants to perform selective stopping tasks before analyzing brain activation patterns.

Effects of negative content on the processing of gender information: an event-related potential study.

Previous research on emotion in language has mainly concerned the impact of emotional information on several aspects of lexico-semantic analyses of single words. However, affective influences on morphosyntactic processing are less understood. In the present study, we focused on the impact of negative valence in the processing of gender agreement relations. Event-related potentials (ERPs) were recorded while participants read three-word phrases and performed a syntactic judgment task. Negative and neutral adjectives could agree or disagree in gender with the preceding noun. At an electrophysiological level, the amplitude of a left anterior negativity (LAN) to gender agreement mismatches decreased in negative words, relative to neutral words. The behavioral data suggested that LAN amplitudes might be indexing the processing costs associated with the detection of gender agreement errors, since the detection of gender mismatches resulted in faster and more accurate responses than did the detection of correct gender agreement relations. According to this view, it seems that negative content facilitated the processes implicated in the early detection of gender agreement mismatches. However, gender agreement violations in negative words triggered processes involved in the reanalysis and repair of the syntactic structure, as reflected in larger P600 amplitudes to incorrect than to correct phrases, irrespective of their emotional valence.