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The neural processes subserving working memory, and brain structures underlying this system, continue to develop during childhood. We investigated the effects of age and gender on audiospatial and visuospatial working memory in a nonclinical sample of school-aged children using n-back tasks. The results showed that auditory and visual working memory performance improves with age, suggesting functional maturation of underlying cognitive processes and brain areas. The gender differences found in the performance of working memory tasks suggest a larger degree of immaturity in boys than girls at the age period of 6-10 yr. The differences observed between the mastering of auditory and visual working memory tasks may indicate that visual working memory reaches functional maturity earlier than the corresponding auditory system.

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The present study investigated the development of executive functions (EFs) and their associations with performance and behavior at school in 8-12-year-old children. The EFs were measured by computer-based n-back, Continuous Performance and Go/Nogo tasks. School performance was evaluated by Teacher Report Form (TRF) and behavior by TRF and Child Behavior Checklist. The studied dimensions of EF were cognitive efficiency/speed, working memory/attention and inhibitory control. Strong age effects were found for these cognitive abilities (p values <0.01). Inhibitory control was associated with better adaptive functioning (learning, working hard and behaving well), academic performance and less psychiatric symptoms (p values <0.05), specially in 8-9-year-old children. In this youngest age group low inhibitory control was also associated with teacher-reported inattention (p = 0.042). Low inhibitory control was associated with teacher- and parent-reported internalizing symptoms (p < 0.01). These results suggest that maturational factors may underlie low adaptive functioning and psychiatric symptoms during early school years. Further studies are needed to evaluate the association between inhibition and emotional symptoms.

Using functional magnetic resonance imaging (fMRI), we measured brain activity of human participants while they performed a sentence congruence judgment task in either the visual or auditory modality separately, or in both modalities simultaneously. Significant performance decrements were observed when attention was divided between the two modalities compared with when one modality was selectively attended. Compared with selective attention (i.e., single tasking), divided attention (i.e., dual-tasking) did not recruit additional cortical regions, but resulted in increased activity in medial and lateral frontal regions which were also activated by the component tasks when performed separately. Areas involved in semantic language processing were revealed predominantly in the left lateral prefrontal cortex by contrasting incongruent with congruent sentences. These areas also showed significant activity increases during divided attention in relation to selective attention. In the sensory cortices, no crossmodal inhibition was observed during divided attention when compared with selective attention to one modality. Our results suggest that the observed performance decrements during dual-tasking are due to interference of the two tasks because they utilize the same part of the cortex. Moreover, semantic dual-tasking did not appear to recruit additional brain areas in comparison with single tasking, and no crossmodal inhibition was observed during intermodal divided attention.