Hemispheric asymmetries and cognitive flexibility: an ERP and sLORETA study

Although functional cerebral asymmetries (FCAs) affect all cognitive domains, their modulation of the efficacy of specific executive functions is largely unexplored. In the present study, we used a lateralized version of the task switching paradigm to investigate the relevance of hemispheric asymmetries for cognitive control processes. Words were tachistoscopically presented in the left (LVF) and right visual half field (RVF). Participants had to categorise the words either based on their initial letters, or according to their word type. On half of the trials the task changed (switch trials) whereas on the other half it stayed the same (repeat trials). ERPs were recorded and the neural sources of the ERPs were reconstructed using standardised low resolution brain electromagnetic tomography (sLORETA). In the word type task, participants were faster on repeat trials when stimuli were presented in the RVF. In contrast, in the initial letter task participants were faster on repeat trials and in general more accurate after stimulus presentation in the LVF. In both tasks, no hemispheric asymmetries in reaction times were observed on switch trials. On the electrophysiological level, we observed a left lateralization of the N1 that was mediated by activation in the left extrastriate cortex as well as a greater positivity of the P3b after stimulus presentation in the RVF compared to the LVF that was mediated by activation in the superior parietal cortex. These results show that FCAs affect the neurophysiological correlates of executive functions related to task switching. The relation of neurophysiological and behavioural asymmetries is mediated by task complexity, with more complex tasks leading to more interhemispheric interaction and smaller left-right differences in behavioural measures. These findings reveal that FCAs are an important modulator of executive functions related to cognitive flexibility.     

Age-Related Changes in Executive Function: A Normative Study with the Dutch Version of the Behavior Rating Inventory of Executive Function (BRIEF)

This study examined age-related change in executive function by using a Dutch translation of the Behavior Rating Inventory of Executive Function (BRIEF; Gioia et al., 2000 Gioia, G. A., Isquith, P. K., Guy, S. C. and Kenworthy, L. 2000. Behavior Rating Inventory of Executive Function BRIEF): Professional manual, Lutz, FL: Psychological Assessment Resources.  [Google Scholar]) that was applied to a normative sample (age range 5–18 years). In addition, we examined the reliability and factorial structures of the Dutch BRIEF. Results with respect to age revealed a decrease in reported executive function problems with increasing age. On the Behavior Regulation Index (BRI), 5- to 8-year-olds showed significantly more executive function problems than 9- to 11-year-olds, as did the 12- to 14-year-olds compared to 15- to 18-year-olds (except on the Shift subscale). On the Metacognition Index, we found that 9- to 11-year-olds differed significantly from 5- to 8-year-olds on the Working Memory subscale. In addition, the current study showed that the internal consistency of the Dutch BRIEF is very high, and that this version of the BRIEF has a high test-retest stability. Item factor analysis confirmed the expected eight common factor model, and factor analysis of the eight test scores confirmed the two-factor model, as proposed by Gioia et al., in the Dutch data.     

不同性质的评价对特质焦虑者抑制功能影响的ERP研究

特质焦虑者作为焦虑障碍易感性个体,会表现出对威胁性刺激的注意偏向,从而损害中央执行系统的抑制功能。但是不同情绪性评价刺激会如何调控特质焦虑者的抑制功能还不太清楚。为此,本研究以脑电P3b为抑制功能指标,要求高低特质焦虑组在三种不同评价下完成反向眼跳范式,考察不同性质的评价如何影响特质焦虑的抑制功能。行为结果发现,高焦虑组比低焦虑组错误率更高;积极评价条件下,高焦虑组的反应时慢于低焦虑组。ERP结果进一步发现,无评价条件下,高焦虑组的P3b波幅大于低焦虑组;低焦虑者在积极评价条件下的P3b波幅大于消极评价条件,但是高焦虑者没有显著差异。结果表明,积极评价会损害高特质焦虑者的抑制功能,而消极评价则促进了高特质焦虑个体的抑制功能。