Home assessment of visual working memory in pre-schoolers reveals associations between behaviour, brain activation and environmental measures.

Abstract

Visual working memory (VWM) is reliably predictive of fluid intelligence and academic achievements. The objective of the current study was to investigate the nature of individual differences in pre-schoolers by examining the relationship between behaviour-brain function underlying VWM processing and parent-reported measures. We used a portable 8 x 8 channel functional near-infrared spectroscopy system to record from the frontal and parietal cortices of 4.5-year-old pre-school children (N=74) as they completed a colour change detection VWM task in their homes. Parents were asked to fill in questionnaires on temperament, academic aspirations, home environment, and life stress. Children were median-split into a low-performing (LP) and a high-performing (HP) group based on the number of items they could successfully remember during the task. LPs increasingly activated the bilateral frontal and parietal cortices with increasing load, whereas HPs showed no difference in activation across the loads. Our findings suggested that LPs recruited more neural resources when their VWM capacity was challenged. We employed mediation analyses to examine the association between the difference in activation between the highest and lowest loads, and variables from the questionnaires. The difference in activation in the right parietal cortex partially mediated the association between parent-reported stressful life events and VWM performance. Specifically, a higher number of stressful events was associated with lower VWM performance. Critically, our findings show that the association between VWM capacity, right parietal activation, and indicators of life stress is important to understand the nature of individual differences in VWM in pre-school children.