How semantic categorization influences inhibitory processing in middle-childhood: an Event Related Potentials study

EEG theta and alpha oscillations in early versus late mild cognitive impairment during a semantic Go/NoGo task

Amnestic mild cognitive impairment (aMCI) is marked by episodic memory deficits, which can be used to classify individuals into early MCI (EMCI) and late MCI (LMCI). Although mounting evidence suggests that individuals with aMCI have additional cognitive alterations including deficits in cognitive control, few have examined if EMCI and LMCI differ on processes other than episodic memory. Using a semantic Go/NoGo task, we examined differences in cognitive control between EMCI and LMCI on behavioral (accuracy and reaction time) and neural (scalp-recorded event-related oscillations in theta and alpha band) measures. Although no behavioral differences were observed between the EMCI and LMCI groups, differences in neural oscillations were observed. The LMCI group had higher theta synchronization on Go trials at central electrodes compared to the EMCI group. In addition, the EMCI group showed differences in theta power at central electrodes and alpha power at central and centro-parietal electrodes between Go and NoGo trials, while the LMCI group did not exhibit such differences. These findings suggest that while behavioral differences may not be observable, neural changes underlying cognitive control processes may differentiate EMCI and LMCI stages and may be useful to understand the trajectory of aMCI in future studies.

Relaciones conceptuales: comparación entre Niños, Adultos Jóvenes y Adultos Mayores

El estudio de la organización del conocimiento en la memoria semántica suscita gran interés en Psicología Cognitiva y Neuropsicología. El conocimiento semántico está representado por conceptos que comparten características y forman una jerarquía inclusiva -organización taxonómica-, o que se vinculan en tiempo y espacio -organización temática o situacional-. Se considera que a lo largo del desarrollo cambia la preferencia por estos tipos de organización, pero son pocos los estudios que comparan las organizaciones conceptuales de niños en edad escolar, adultos jóvenes y mayores, y sus resultados son divergentes. Asimismo, la organización conceptual también varía en función del dominio al que pertenece el concepto (vivo vs no vivo). Por lo tanto, el objetivo general de este estudio fue estudiar qué tipos de organización conceptual empleaban esos grupos en una tarea de producción de atributos para conceptos de seres vivos y no vivos. Los resultados indican que la producción de atributos taxonómicos fue significativamente mayor para los adultos jóvenes que para los adultos mayores y los niños, en tanto la producción taxonómica de estos dos últimos grupos fue pareja. En cuanto a la producción temática, fue alta y homogénea en los tres grupos de edad. Por último, para el dominio de los seres no vivos los atributos resultaron en su mayoría temáticos y perceptivos, y para el dominio de los seres vivos, mayormente perceptivos.

The Effectiveness of Physical Activity Interventions for Low-Income and Ethnic Minority Children and Youths: A Meta-Analysis

Background: Children and youths from low-income families and certain ethnic minority groups show high levels of risk and vulnerability to physical inactivity. The aim of this review was to examine the effectiveness of interventions to increase physical activity (PA) in children and youths from low-income and ethnic minority (LIEM) families. Methods: Eight databases were systematically searched for PA interventions for LIEM children and youths. Twenty-six studies were included in the analyses. Effect sizes (ESs) were calculated using a random-effects model. The ESs were computed using Hedges g with 95% confidence interval. Results: There were small to medium effects of interventions on PA in LIEM children and youth (Q = 1499.193, df = 30, P < .05; I2 = 97.999). Analyses on the moderator variables showed that ES for participants aged 9–12 years (ES = 0.542, P = .01); intervention length less than 13 weeks (ES = 0.561, P = .01); specialists as the intervention agent (ES = 0.680, P < .05); interventions without technology (ES = 0.363, P = .02); and interventions with a behavioral modification component (ES = 0.336, P = .03) were significantly different from zero. Conclusion: PA intervention can be an effective strategy to increase PA for LIEM children and youths.

Event-related neural oscillation changes following reasoning training in individuals with Mild Cognitive Impairment

Emerging evidence suggests cognitive training programs targeting higher-order reasoning may strengthen not only cognitive, but also neural functions in individuals with Mild Cognitive Impairment (MCI). However, research on direct measures of training-induced neural changes, derivable from electroencephalography (EEG), is limited. The current pilot study examined effects of Gist Reasoning training (n = 16) compared to New Learning training (n = 16) in older adults with amnestic MCI on measures of event-related neural oscillations (theta and alpha band power) corresponding to Go/NoGo tasks during basic and superordinate semantic categorization. EEG data were recorded while participants performed the Go/NoGo task pre- and post-training, and power in theta and alpha frequency bands was examined. Both groups were comparable at pre-training on all measures and both groups showed greater event-related theta synchronization post-training. Furthermore, the Gist Reasoning group had enhanced event-related desynchronization in low-frequency alpha band (8-10 Hz) on response inhibition (NoGo) trials and high-frequency alpha band (11-13 Hz) on response execution (Go) trials during superordinate categorization, relative to the New Learning group. These findings suggest that Gist Reasoning training in MCI impacted neural processing linked to strategic processing of Go and NoGo trials during the more complex superordinate categorization task. Targeting higher-order top-down cognitive processing seems to better harness residual neuroplastic potential in MCI. ClinicalTrials.gov ID: NCT02588209.

Theta and Alpha Alterations in Amnestic Mild Cognitive Impairment in Semantic Go/NoGo Tasks

Growing evidence suggests that cognitive control processes are impaired in amnestic mild cognitive impairment (aMCI); however the nature of these alterations needs further examination. The current study examined differences in electroencephalographic theta and alpha power related to cognitive control processes involving response execution and response inhibition in 22 individuals with aMCI and 22 age-, sex-, and education-matched cognitively normal controls. Two Go/NoGo tasks involving semantic categorization were used. In the basic categorization task, Go/NoGo responses were made based on exemplars of a single car (Go) and a single dog (NoGo). In the superordinate categorization task, responses were made based on multiple exemplars of objects (Go) and animals (NoGo). Behavioral data showed that the aMCI group had more false alarms during the NoGo trials compared to controls. The EEG data revealed between group differences related to response type in theta (4–7 Hz) and low-frequency alpha (8–10 Hz) power. In particular, the aMCI group differed from controls in theta power during the NoGo trials at frontal and parietal electrodes, and in low-frequency alpha power during Go trials at parietal electrodes. These results suggest that alterations in theta power converge with behavioral deterioration in response inhibition, whereas alterations in low-frequency alpha power appear to precede behavioral changes in response execution. Both behavioral and electrophysiological correlates combined provide a more comprehensive characterization of cognitive control deficits in aMCI.

Effects of age on cognitive control during semantic categorization

We used event-related potentials (ERPs) to study age effects of perceptual (basic-level) vs. perceptual-semantic (superordinate-level) categorization on cognitive control using the go/nogo paradigm. Twenty-two younger (11 M; 21 ± 2.2 years) and 22 older adults (9 M; 63 ± 5.8 years) completed two visual go/nogo tasks. In the single-car task (SiC) (basic), go/nogo responses were made based on single exemplars of a car (go) and a dog (nogo). In the object animal task (ObA) (superordinate), responses were based on multiple exemplars of objects (go) and animals (nogo). Each task consisted of 200 trials: 160 (80%) 'go' trials that required a response through button pressing and 40 (20%) 'nogo' trials that required inhibition/withholding of a response. ERP data revealed significantly reduced nogo-N2 and nogo-P3 amplitudes in older compared to younger adults, whereas go-N2 and go-P3 amplitudes were comparable in both groups during both categorization tasks. Although the effects of categorization levels on behavioral data and P3 measures were similar in both groups with longer response times, lower accuracy scores, longer P3 latencies, and lower P3 amplitudes in ObA compared to SiC, N2 latency revealed age group differences moderated by the task. Older adults had longer N2 latency for ObA compared to SiC, in contrast, younger adults showed no N2 latency difference between SiC and ObA. Overall, these findings suggest that age differentially affects neural processing related to cognitive control during semantic categorization. Furthermore, in older adults, unlike in younger adults, levels of categorization modulate neural processing related to cognitive control even at the early stages (N2).

Improving data retention in EEG research with children using child-centered eye tracking

BACKGROUND

Event Related Potentials (ERPs) elicited by visual stimuli have increased our understanding of developmental disorders and adult cognitive abilities for decades; however, these studies are very difficult with populations who cannot sustain visual attention such as infants and young children. Current methods for studying such populations include requiring a button response, which may be impossible for some participants, and experimenter monitoring, which is subject to error, highly variable, and spatially imprecise.

NEW METHOD

We developed a child-centered methodology to integrate EEG data acquisition and eye-tracking technologies that uses "attention-getters" in which stimulus display is contingent upon the child's gaze. The goal was to increase the number of trials retained. Additionally, we used the eye-tracker to categorize and analyze the EEG data based on gaze to specific areas of the visual display, compared to analyzing based on stimulus presentation.

RESULTS COMPARED WITH EXISTING METHODS

The number of trials retained was substantially improved using the child-centered methodology compared to a button-press response in 7-8 year olds. In contrast, analyzing the EEG based on eye gaze to specific points within the visual display as opposed to stimulus presentation provided too few trials for reliable interpretation.

CONCLUSIONS

By using the linked EEG-eye-tracker we significantly increased data retention. With this method, studies can be completed with fewer participants and a wider range of populations. However, caution should be used when epoching based on participants' eye gaze because, in this case, this technique provided substantially fewer trials.

Internal consistency of event-related potentials associated with cognitive control: N2/P3 and ERN/Pe

Recent studies in psychophysiology show an increased attention for examining the reliability of Event-Related Potentials (ERPs), which are measures of cognitive control (e.g., Go/No-Go tasks). An important index of reliability is the internal consistency (e.g., Cronbach's alpha) of a measure. In this study, we examine the internal consistency of the N2 and P3 in a Go/No-Go task. Furthermore, we attempt to replicate the previously found internal consistency of the Error-Related Negativity (ERN) and Positive-Error (Pe) in an Eriksen Flanker task. Healthy participants performed a Go/No-Go task and an Eriksen Flanker task, whereby the amplitudes of the correct No-Go N2/P3, and error trials for ERN/Pe were the variables of interest. This study provides evidence that the N2 and P3 in a Go/No-Go task are internally consistent after 20 and 14 trials are included in the average, respectively. Moreover, the ERN and Pe become internally consistent after approximately 8 trials are included in the average. In addition guidelines and suggestions for future research are discussed.

Semantic processing and response inhibition

The present study examined functional MRI (fMRI) BOLD signal changes in response to object categorization during response selection and inhibition. Young adults (N=16) completed a Go/NoGo task with varying object categorization requirements while fMRI data were recorded. Response inhibition elicited increased signal change in various brain regions, including medial frontal areas, compared with response selection. BOLD signal in an area within the right angular gyrus was increased when higher-order categorization was mandated. In addition, signal change during response inhibition varied with categorization requirements in the left inferior temporal gyrus (lIT). lIT-mediated response inhibition when inhibiting the response only required lower-order categorization, but lIT mediated both response selection and inhibition when selecting and inhibiting the response required higher-order categorization. The findings characterized mechanisms mediating response inhibition associated with semantic object categorization in the 'what' visual object memory system.

Neural substrates of the development of cognitive control in children ages 5-10 years

Cognitive conflict detection and resolution develops with age across childhood and likely supports age-related increases in other aspects of cognitive and emotional development. Little is known about the neural correlates of conflict detection and resolution in early childhood. In the current study, we investigated age-related change in neural recruitment during a blocked spatial-incompatibility task (Simon task) in children ages 5-10 years using fMRI. Cortical thickness was measured using structural MRI. Across all children, there was greater activation in right prefrontal and bilateral parietal cortices for incompatible than compatible conditions. In older children, compared with younger children, there was decreased activation and decreased gray matter thickness in the medial PFC. Thickness and activation changes across age were associated within participants, such that thinner cortex was associated with less activation in the rostral ACC. These findings suggest that developmental change in medial PFC activation supports performance on cognitive control tasks in early childhood.

Previous reward decreases errors of commission on later 'No-Go' trials in children 4 to 12 years of age: evidence for a context monitoring account

Inhibitory control is widely hypothesized to be the cornerstone of executive function in childhood and the central deficit in a number of developmental disorders, including attention-deficit/hyperactivity disorder (ADHD). However, recent evidence from adults indicates that performance on response inhibition tasks may primarily reflect non-inhibitory attentional control (context monitoring) processes. Yet it may be that inhibition plays a more central role in childhood - a time when the architecture of cognitive processes might be more transparent due to wide variability in skill level. Here we directly test inhibitory and context monitoring explanations of task performance on a Go/No-Go task in a large group of children 4-12 years of age. We conclude that traditional inhibitory conceptualizations of task performance on the Go/No-Go task cannot account for our findings, calling into question evidence supporting a central role for inhibitory control in cognitive development or developmental psychopathology.

Inhibitory control gains from higher-order cognitive strategy training

The present study examined the transfer of higher-order cognitive strategy training to inhibitory control. Middle school students enrolled in a comprehension- and reasoning-focused cognitive strategy training program and passive controls participated. The training program taught students a set of steps for inferring essential gist or themes from materials. Both before and after training or a comparable duration in the case of the passive controls, participants completed a semantically cued Go/No-Go task that was designed to assess the effects of depth of semantic processing on response inhibition and components of event-related potentials (ERP) related to response inhibition. Depth of semantic processing was manipulated by varying the level of semantic categorization required for response selection and inhibition. The SMART-trained group showed inhibitory control gains and changes in fronto-central P3 ERP amplitudes on inhibition trials; whereas, the control group did not. The results provide evidence of the transfer of higher-order cognitive strategy training to inhibitory control and modulation of ERPs associated with semantically cued inhibitory control. The findings are discussed in terms of implications for cognitive strategy training, models of cognitive abilities, and education.