Cognitive training enhances intrinsic brain connectivity in childhood

Abstract

In human participants, the intensive practice of particular cognitive activities can induce sustained improvements in cognitive performance, which in some cases transfer to benefits on untrained activities. Despite the growing body of research examining the behavioral effects of cognitive training in children, no studies have explored directly the neural basis of these training effects in a systematic, controlled fashion. Therefore, the impact of training on brain neurophysiology in childhood, and the mechanisms by which benefits may be achieved, are unknown. Here, we apply new methods to examine dynamic neurophysiological connectivity in the context of a randomized trial of adaptive working memory training undertaken in children. After training, connectivity between frontoparietal networks and both lateral occipital complex and inferior temporal cortex was altered. Furthermore, improvements in working memory after training were associated with increased strength of neural connectivity at rest, with the magnitude of these specific neurophysiological changes being mirrored by individual gains in untrained working memory performance.

Keywords: Cognitive training; development; electrophysiology; magnetoencephalography; working memory.

Figure 1.

The MEG acquisition and analysis pipeline.

Figure 2.

Performance on the standardized working memory assessments in both groups, before and after training. Error bars indicate the SEM.

Figure 3.

A, Red-orange areas correspond to a right hemisphere frontoparietal seed network (Smith et al., 2012). The green area highlights an area of functional interaction with this network that demonstrates a significant interaction between group (Adaptive vs Placebo) and time (pretraining versus posttraining) in the first GLM analysis, corrected for multiple comparisons across voxels, seed networks, and frequencies. B, Connectivity values for left LOC for each intervention group before and after training. C, Changes in connectivity values for individual subjects across both intervention conditions plotted against changes in working memory capacity after training. In all cases, the error bars correspond to the SEM. All of the measures of connectivity show normalized parameter estimates from the GLM.

Figure 4.

A, Red-orange areas correspond to a bilateral seed network including superior parietal and middle frontal gyri (Smith et al., 2012). The green area highlights significant effects of working memory ability posttraining while controlling for working memory ability pretraining. This result is corrected for multiple comparisons across voxels, seed networks, and frequencies. B and C, Relationship between changes in working memory ability (posttraining minus pretraining) and changes in connectivity in the inferior temporal cortex (r = 0.68, p < 0.001) (B) and the superior parietal lobule (r = 0.65, p < 0.001) (C). All of the measures of connectivity show normalized parameter estimates from the GLM.

Figure 5.

The two networks significantly altered after working memory training, which are spatially defined using an independent fc-fMRI dataset from Smith et al. (2012). As in previous figures, any green areas correspond to significant effects from either of the GLM analyses. The lower set of maps shows the result of a spatially blind temporal ICA conducted on the temporally down-sampled concatenated Hilbert envelope data, also in the 13–20 Hz range, before training.