The role of executive function on the reading ability of Chinese adolescents: An fMRI study

This study examined the role of the executive function network on the adolescent reading ability. Previous studies showed that dyslexia is associated with the deficits of cognitive abilities associated with the reading ability of adolescent students (Chung et al., 2009). However, the role of executive function on reading ability is still unclear. In this study, a counting Stroop task is used to activate the executive function network involved in resolving cognitive interference and to examine how the response of this network correlates with the reading ability of typically developing and dyslexic adolescents. The counting Stroop task is a button-press variant of the original Stroop task and is validated for examining the neural substrate of cognitive interference effect in the fMRI environment (Bush et al., 2006). Methods: Three typically developing male adolescents (mean age: 14) and three age-matched diagnosed Hong Kong Chinese adolescents with dyslexia completed two runs of the counting Stroop task while their brain activities were monitored with BOLD fMRI. We hypothesized that, relative to the congruent and neutral trial, the incongruent trial would elicit a stronger BOLD response within the executive function network. The reading ability of the participant is quantified with a digit rapid automatized naming (RAN) task outside the scanner. The RAN task required participants to name a series of Arabic numerals presented on a computer screen as fast as possible. The fMRI experiment was performed with the Philips 3T scanner at the MRI Unit at the University of Hong Kong. The acquired data were analyzed with SPM12. BOLD images were realigned, normalized and smoothed. A two-level statistical paradigm was used to analyze the preprocessed images. A voxel-wise generalized linear model was used to estimate the BOLD response associated with the three conditions. The RAN data were included as a covariate at the second level model. Results and Discussion: The behavioral data of the counting Stroop confirmed the cognitive interference effect that the response time of the incongruent trials is significantly longer than the ones of the congruent and neutral trials. The fMRI data showed that participants’ RAN performance correlated with the BOLD signal at dorsal anterior cingulate cortex (dACC) and dorsolateral prefrontal cortex (DLPFC). More specifically, participants with a higher RAN score exhibited a stronger activation at dACC and DLPFC in the incongruent trial than in the congruent or neutral trial. Our preliminary data indicated that the efficacy of dACC and DLPFC in resolving cognitive interference correlates with the reading ability of Chinese adolescents.