Neural differences in the temporal cascade of reactive and proactive control for bilinguals and monolinguals

Does cognitive control mediate the relationship between peer presence and adolescent risk-taking? An ERP study

Peer presence influences risk-taking behavior, particularly in adolescence. Based on the dual system model, this event-related potential study examined whether and how the presence of a peer displayed a preference for risky behavior would increase adolescents' risk-taking by disrupting their cognitive control processes in either emotional or non-emotional contexts. A sample of 106 adolescents (17-19 years of age) completed two Stoop tasks and a Balloon Analog Risk Task under three peer presence conditions. Results revealed that compared to other conditions, the presence of a risk-averse peer caused adolescents to make safer decisions through improving their conflict monitoring (more negative N200-diff), whereas a risk-preference peer's presence led adolescents to more risky decisions through disrupting their conflict resolution (more positive N450-diff) but they were only observed on the Emotional Stroop task. These findings suggest that different peer presence contexts could increase or decrease adolescents' risk-taking behaviors by influencing their cognitive control under an emotional context rather than in a non-emotional context.

Associations between physical activity and proactive control and the modulating role of working memory

Accumulating evidence indicates positive associations between physical activity (PA) and cognitive control. Proactive control, the ability to maintain goal-relevant information in preparation of upcoming task demands, is a critical component of cognitive control. However, little research has examined the association between PA and proactive control. To address this issue, a total of 132 university students were recruited and divided into two groups based on reported regular PA during past week. All participants completed two common cognitive control tasks: the AX Continuous Performance Task (AX-CPT) and the Cued Task-Switching Paradigm (CTS). In comparison with the low PA group, the high PA group showed greater proactive control efficiency on both tasks. Moreover, proactive control indices significantly correlated between the two tasks for the high but not for the low PA group. Further, working memory significantly modulated the association between PA and proactive control efficiency of CTS. Although the present cross-section design does not allow us to test the causal relationship between PA and proactive control, these findings may have important implications for developing effective intervention strategies which aim to promote proactive control through increasing PA or to promote PA through increasing proactive control. Moreover, individual differences in working memory are important to consider when we aim to design such interventions.

Control mechanisms in voluntary versus mandatory language switching: Evidence from ERPs

The present study measured event-related potentials (ERP) and behavioral performance to examine whether inhibitory control is involved in voluntary language switching, and if so, to explore the differences in inhibitory control between voluntary and mandatory language switching. Unbalanced Chinese-English bilinguals completed two picture naming tasks: one involving mandatory language switches and one in which participants could voluntarily switch between the two languages. Behavioral data showed significant switch costs and a reversed language dominance effect in both switching tasks. Critically, both effects were larger in mandatory compared to voluntary switching. ERP results revealed that neural switch costs during mandatory switching was significantly different than voluntary switching in both N2 and LPC amplitudes. In contrast, a significant difference in the reversed language dominance effect between both tasks was only observed in LPC amplitude. Together, these findings suggest the involvement of inhibitory control in both mandatory and voluntary language switching, but the degree of inhibition and the time-course of control processes between both tasks appear to be distinct.

A Novel Perspective on the Proactive and Reactive Controls of Executive Function in Chronic Stroke Patients

Objectives

To investigate the proactive and reactive control process when executing a complex task in patients with stroke. Proactive control is the preparatory process before the target stimulus, whereas reactive control is an imperative resolution of interference after the target stimulus.

Methods

In total, 17 patients with chronic stroke and 17 healthy individuals were recruited. The proactive and reactive control of executive function was assessed by the task-switching paradigm and the AX version of the Continuous Performance Task (AX-CPT). The general executive function was assessed by Color Trial Test (CTT) and Stroop Test. The behavioral data of the task-switching paradigm were analyzed by a three-way repeated-measures ANOVA, and the AX-CPT data were analyzed by two-way repeated-measures ANOVA.

Results

For efficiency scores in the task-switching paradigm, trial (repeat vs. switch) × group (stroke or control group) interaction effect was significant. Post-hoc analysis on trial × group effect showed a significant between-trial difference in accuracy rates in the repeat trial in the control group regardless of 100 or 50% validity. For the AX-CPT, the main effects of condition and group on response time were statistically significant. The interaction effect of condition (AY or BX) × group (stroke or control group) was also significant. Post-hoc analysis for condition × group indicated that the stroke group had a significantly longer response time in the BX condition than the control group and longer completion time in CTT2 and larger word interference for completion time in the Stroop test than the control cohort.

Conclusions

Post-stroke survivors showed deficits in the performance of proactive control but not in the performance of reactive control. Deficits in proactive control may be related to the impairment of working memory. Interventions that focus on proactive control may result in improved clinical outcomes.