Brain connectivity during verbal working memory in children and adolescents

Abstract

Working memory (WkM) is a fundamental cognitive process that serves as a building block for higher order cognitive functions. While studies have shown that children and adolescents utilize similar brain regions during verbal WkM, there have been few studies that evaluate the developmental differences in brain connectivity. Our goal was to study the development of brain connectivity related to verbal WkM in typically developing children and adolescents. Thirty-five healthy children and adolescents, divided into three groups: 9–12 (children), 13–16 (young adolescents) and 17–19 (older adolescents) years, were included in this fMRI study. The verbal WkM task involved a modified Sternberg item recognition paradigm using three different loads. Brain connectivity analysis was performed using independent component analyses and regressing the components with the design matrix to determine task-related networks. Connectivity analyses resulted in four components associated solely with encoding, four solely with recognition and two with both. Two networks demonstrated age-related differences with respect to load, 1) the left motor area and right cerebellum, and 2) the left prefrontal cortex, left parietal lobe, and right cerebellum. Post hoc analyses revealed that the first network showed significant effects of age between children and the two older groups. There was increasing connectivity with increasing load for adolescents. The second network demonstrated age-related differences between children and older adolescents. Children have higher task-related connectivity at lower loads, but they tend to equalize with the adolescents with higher loads. Finally, a non-load related network involving the orbital frontal and anterior cingulate cortices showed less connectivity in children.

The developmental neural substrates of item and serial order components of verbal working memory

“…The few studies focusing on storage processes were mostly in the visuospatial domain and showed age‐related differences, with an increase of activations in the parietal network and to some extent in the frontal areas (Kharitonova et al, ; Klingberg et al, ; Spencer‐Smith et al, ; Thomason et al, ). One study focusing on verbal maintenance and recognition via a modified Sternberg item recognition task (Van den Bosch et al, ) demonstrated similar results with an increase in the left motor area and right cerebellum, left prefrontal, and left parietal cortex activations when they considered age as a continuous variable. However, no study so far has specifically investigated the neural aspects that support the development of serial order versus item WM.…”

“…At a more general, developmental level, the age‐related differences in WM neural networks observed in this study, particularly for serial order WM, are in line with the hypothesis of a progressive neural specialization for WM that is not yet fully established in young children (Kharitonova et al, ; Klingberg et al, ; Spencer‐Smith et al, ; Thomason et al, ). While some neuroimaging studies observed a similar frontoparietal network involvement for WM tasks in children, adolescents, and adults (Thomason et al, ; Ciesielski et al, ; Siffredi et al, ; Klingberg et al, 2006; Scherf et al, ), other studies showed that activation levels of the parietal and prefrontal cortex increased with age (Crone et al, ; Kharitonova et al, ; Klingberg et al, ; Kwon et al, ; Spencer‐Smith et al, ; Thomason et al, ; Van den Bosch et al, ). In the present study, we observed similar levels of neural activity in young and older children, except for frontoparietal involvement specifically in the serial order WM condition, and which appeared to increase with age.…”

Building an adaptive brain across development: targets for neurorehabilitation must begin in infancy

“…The region appears to play an integral role in subvocal rehearsal and is especially important when demands on timing, memory and morpho-syntactic processing increase (Ackermann et al, 2007 ; Mariën et al, 2014 ). Both imaging and lesion studies indicate that the cerebellum is involved in numerous aspects of language processing, including verbal working memory, phonological processing, semantic processing, and verbal fluency (Marvel and Desmond, 2010 ; van den Bosch et al, 2014 ; Highnam and Bleile, 2015 ). The cerebellum also forms part of a network of regions modulating grammar and is believed to be involved in analyzing the details of speech for regularity based on grammatical rules (Caplan and Dapretto, 2001 ; Mariën et al, 2014 ).…”

Ten Key Observations on the Analysis of Resting-state Functional MR Imaging Data Using Independent Component Analysis

“…ICA benefits from many existing approaches that have strong assumptions. For example, GLM approaches are often used to perform testing on the data-driven component time courses or maps (eg, to identify task-related components 47–49 ). In essence, ICA is used to extract spatial maps and time courses from the data that can act as a fertile analytical substrate to be evaluated or tested in multiple ways using preferred frameworks.…”