Electrophysiological evidence for different effects of working memory load on interference control in adolescents than adults

Age differences in the principal temporo-spatial components of EEG activity during a proactive interference task

Proactive interference (PI) is the disruptive effect of no longer relevant information on current working memory (WM) processing. PI effects in EEG data have been previously found to be altered in healthy aging, although it remains unclear the extent to which such changes reflect delayed or different brain mechanisms employed to overcome PI. Hence, we had twenty-six young (18-34 years) and sixteen old (53-68 years) healthy adults complete a Recent Probes task while EEG was recorded. Compared to young adults, old adults were slower, less accurate and less able to discriminate when they last saw a given stimulus, but PI effects on reaction time were greater in the former, likely due to a general difficulty that old adults had in the task. Temporo-spatial principal component analysis of the EEG data showed young and older adults to differ in terms of temporal and spatial characteristics of brain activity associated with resolving PI. YA showed a factor indicative of a medial frontal negativity (MFN) that showed greater amplitude in low compared to high PI trials. OA, in contrast, showed a late positive component (LPC), although similarly with larger amplitude in low compared to high PI trials. The modulation of the MFN component in YA may reflect the recruitment of cognitive control to overcome PI. The modulation of the LPC in OA may represent the detection of conflict between familiarity and context recollection during PI.

Differential Impact of WM Load on Attention in Young Adults Versus Children and Adolescents

Background: This study aimed to examine how concurrent working memory (WM) loads affect selective attention, and to explore developmental differences between young adults and children/adolescents aged 10 to 14 years. Methods: We employed a modified Stroop task with verbal or spatial WM loads to assess their impact on attention. Results: In adults, we found increased Stroop effects when WM load overlapped with target processing and decreased Stroop effects when WM load overlapped with distractor processing. Conversely, in children/adolescents, WM loads did not significantly impact target or distractor processing, indicating no change in Stroop effects under dual-task conditions. Interestingly, results from the correlational analyses revealed that as participants' ages increase, the interference effect under the WM load that shares resources with distractor processing in the attention task decreases. Conclusions: Our findings suggest that the interaction between attention and WM differs across developmental stages. While adults showed distinctive effects of concurrent WM loads on attention processing depending on the cognitive resources utilized, children/adolescents failed to show the interaction between the two cognitive systems. Furthermore, a significant relationship between age and the effects of WM load on attention was observed, providing insights into the development of the interaction between WM and attention.

Temporal Course of Interference Control from Early to Late Young Adulthood: An ERP Study

In the present study, we aimed to investigate the neural dynamics of interference control using event-related potentials (ERPs) to reveal time course of interference control from the beginning to the end of young adulthood. Three groups of participants aged 19-21, 23-27 and 28-44 performed a Stroop task. The results revealed age differences in both accuracy and ERP amplitudes during all aspects of interreference control processing that reflect selective attention (P2), conflict monitoring (N2), conflict evaluation (P3) and interference control (N450). Both younger groups made more errors on incongruent trials compared to participants in their early 30s. The presence of higher P2 and N2 amplitudes, diminished P3 and again higher N450 amplitudes in participants in their early 20s points to a shortage of available resources for top-down control at this age. These results are in accordance with structural and functional studies that show that development of the frontoparietal network, which underlies interference control, continues after adolescence. While brain mechanisms are still developing, the use of accompanying cognitive abilities is still not optimal. The findings that change in neural dynamics and related performance continues into early adulthood challenge current models of cognitive development and call for new directions in developmental theorizing.

Emotional prosody Stroop effect in Hindi: An event related potential study

Prosody processing is an important aspect of language comprehension. Previous research on emotional word-prosody conflict has shown that participants are worse when emotional prosody and word meaning are incongruent. Studies with event-related potentials have shown a congruency effect in N400 component. There has been no study on emotional processing in Hindi language in the context of conflict between emotional word meaning and prosody. We used happy and angry words spoken using happy and angry prosody. Participants had to identify whether the word had a happy or angry word meaning. The results showed a congruency effect with worse performance in incongruent trials indicating an emotional Stroop effect in Hindi. The ERP results showed that prosody information is detected very early, which can be seen in the N1 component. In addition, there was a congruency effect in N400. The results show that prosody is processed very early and emotional meaning-prosody congruency effect is obtained with Hindi. Further studies would be needed to investigate similarities and differences in cognitive control associated with language processing.

The effect of age, educational level, gender and cognitive reserve on visuospatial working memory performance across adult life span

Working memory (WM) is a limited capacity cognitive system that temporarily holds information for processing. In the present study, we tested the effect of age, gender and cognitive reserve in terms of educational level, working and leisure time activities on an active visuospatial WM task. One-hundred thirty-four participants between 20 and 80 years old performed an n-back task with different degree of WM demanding. Reaction times (RTs) became slower and accuracy decreased with age; the former started to decline in participants that were 35 years old, the latter in participants that were 57 years old. Males were faster than females. Educational level (10 years in accuracy and 15 years in RTs) showed a positive effect on accuracy and RTs. Cognitive reserve had a positive effect on accuracy but no effect on RTs. In conclusion, age-related decline influenced earlier the speed and later the accuracy in a task that required active processes. While male was faster independently of WM demanding and age, middle school degree and an average cognitive reserve prevent errors during performance. Coherently, high school degree prevents slowing down but only in low demanding condition.

Investigating the influence of working memory capacity when driving behavior is combined with cognitive load: An LCT study of young novice drivers

Distracted driving has received increasing attention in the literature due to potential adverse safety outcomes. An often posed solution to alleviate distraction while driving is hands-free technology. Interference by distraction can occur however at the sensory input (e.g., visual) level, but also at the cognitive level where hands-free technology induces working memory (WM) load. Active maintenance of goal-directed behavior in the presence of distraction depends on WM capacity (i.e., Lavie's Load theory) which implies that people with higher WM capacity are less susceptible to distractor interference. This study investigated the interaction between verbal WM load and WM capacity on driving performance to determine whether individuals with higher WM capacity were less affected by verbal WM load, leading to a smaller deterioration of driving performance. Driving performance of 46 young novice drivers (17-25 years-old) was measured with the lane change task (LCT). Participants drove without and with verbal WM load of increasing complexity (auditory-verbal response N-back task). Both visuospatial and verbal WM capacity were investigated. Dependent measures were mean deviation in the lane change path (MDEV), lane change initiation (LCI) and percentage of correct lane changes (PCL). Driving experience was included as a covariate. Performance on each dependent measure deteriorated with increasing verbal WM load. Meanwhile, higher WM capacity related to better LCT performance. Finally, for LCI and PCL, participants with higher verbal WM capacity were influenced less by verbal WM load. These findings entail that completely eliminating distraction is necessary to minimize crash risks among young novice drivers.

Dissociation of preparatory attention and response monitoring maturation during adolescence

OBJECTIVE

Substantial brain development occurs during adolescence providing the foundation for functional advancement from stimulus-bound "bottom-up" to more mature executive-driven "top-down" processing strategies. The objective was to assess development of EEG markers of these strategies and their role in both preparatory attention (contingent negative variation, CNV) and response monitoring (Error Related Negativity, ERN, and Correct Related Negativity, CRN).

METHODS

CNV, ERN and CRN were assessed in 38 adolescents (18 girls), age 11-18 years, using a variation of a letter discrimination task.

RESULTS

Accuracy increased with age and developmental stage. Younger adolescents used a posterior attention network involved in inhibiting irrelevant information. Activity in this juvenile network, as indexed by a posteriorly-biased CNV and CRN decreased with age and advancing pubertal development. Although enhanced frontal CNV, known to be predictive of accuracy in adults, was not detected even in the older adolescents, top-down medial frontal response monitoring processes (ERN) showed evidence of development within the age-range studied.

CONCLUSIONS

The data revealed a dissociation of developmental progress, marked by relatively delayed onset of frontal preparatory attention relative to error monitoring.

SIGNIFICANCE

This dissociation may render adolescents vulnerable to excessive risk-taking and disinhibited behavior imposed by asynchronous development of component cognitive control processes.

Low-arousal speech noise improves performance in N-back task: an ERP study

The relationship between noise and human performance is a crucial topic in ergonomic research. However, the brain dynamics of the emotional arousal effects of background noises are still unclear. The current study employed meaningless speech noises in the n-back working memory task to explore the changes of event-related potentials (ERPs) elicited by the noises with low arousal level vs. high arousal level. We found that the memory performance in low arousal condition were improved compared with the silent and the high arousal conditions; participants responded more quickly and had larger P2 and P3 amplitudes in low arousal condition while the performance and ERP components showed no significant difference between high arousal and silent conditions. These findings suggested that the emotional arousal dimension of background noises had a significant influence on human working memory performance, and that this effect was independent of the acoustic characteristics of noises (e.g., intensity) and the meaning of speech materials. The current findings improve our understanding of background noise effects on human performance and lay the ground for the investigation of patients with attention deficits.

A cognitive framework for understanding and improving interference resolution in the brain

All of us are familiar with the negative impact of interference on achieving our task goals. We are referring to interference by information, which either impinges on our senses from an external environmental source or is internally generated by our thoughts. Informed by more than a decade of research on the cognitive and neural processing of interference, we have developed a framework for understanding how interference impacts our neural systems and especially how it is regulated and suppressed during efficient on-task performance. Importantly, externally and internally generated interferences have distinct neural signatures, and further, distinct neural processing emerges depending on whether individuals must ignore and suppress the interference, as for distractions, or engage with them in a secondary task, as during multitasking. Here, we elaborate on this cognitive framework and how it changes throughout the human lifespan, focusing mostly on research evidence from younger adults and comparing these findings to data from older adults, children, and cognitively impaired populations. With insights gleaned from our growing understanding, we then describe three novel translational efforts in our lab directed at improving distinct aspects of interference resolution using cognitive training. Critically, these training approaches were specifically developed to target improved interference resolution based on neuroplasticity principles and have shown much success in randomized controlled first version evaluations in healthy aging. Our results show not only on-task training improvements but also robust generalization of benefit to other cognitive control abilities. This research showcases how an in-depth understanding of neural mechanisms can then inform the development of effective deficit-targeted interventions, which can in turn benefit both healthy and cognitively impaired populations.

On the interaction between sad mood and cognitive control: the effect of induced sadness on electrophysiological modulations underlying Stroop conflict processing

The present study employed high-density ERPs to examine the effect of induced sad mood on the spatiotemporal correlates of conflict monitoring and resolution in a colour-word Stroop interference task. Neuroimaging evidence and dipole modelling implicates the involvement of the anterior cingulate cortex (ACC) and medial prefrontal cortex (mPFC) regions in conflict-laden interference control. On the basis that these structures have been found to mediate emotion-cognition interactions in negative mood states, it was predicted that Stroop-related cognitive control, which relies heavily on anterior neural sources, would be affected by effective sad mood provocation. Healthy participants (N=14) were induced into transient sadness via use of autobiographical sad scripts, a well-validated mood induction technique (Liotti et al., 2000a, 2002). In accord with previous research, interference effects were shown at both baseline and sad states while Stroop conflict was associated with early (N450) and late (Late Positive Component; LPC) electrophysiological modulations at both states. Sad mood induction attenuated the N450 effect in line with our expectation that it would be susceptible to modulation by mood, given its purported anterior limbic source. The LPC effect was displayed at the typical posterior lateral sites but, as predicted, was not affected by sad mood. However, frontocentral LPC activity-presumably generated from an additional anterior limbic source-was affected at sad state, hinting a role in conflict monitoring. Although the neurophysiological underpinnings of interference control are yet to be clarified, this study provided further insight into emotion-cognition interactions as indexed by Stroop conflict-laden processing.