General Intelligence Is Associated with Working Memory-Related Functional Connectivity Change: Evidence from a Large-Sample Study

BACKGROUND/PURPOSE Psychometric intelligence is closely related to working memory (WM) and the associated brain activity. We aimed to clarify the associations between psychometric intelligence and WM-induced functional connectivity changes. METHODS Here we determined the associations between psychometric intelligence measured by non-verbal reasoning (using the Raven's Advanced Progressive Matrix) and WM-induced changes in functional connectivity during the N-back paradigm, in a large cohort of 1221 young adults. RESULTS We observed that the measures of general intelligence showed a significant positive correlation with WM-induced changes in the functional connectivity with the key nodes of the fronto-parietal network, such as the bilateral premotor cortices and the pre-SMA. Those significant correlations were observed for (a) areas showing a WM-induced increase of the functional connectivity with the abovementioned key nodes, such as the lateral parietal cortex, (b) areas showing a WM-induced decrease of the functional connectivity with the abovementioned key nodes, (b-1) such as left perisylvian areas and cuneus, the fusiform gyrus, and the lingual gyrus, which play key roles in language processing, (b-2) hippocampus, and parahippocampal gyrus, which play key roles in memory processing, and (b-3) the key node of the default mode network such as the medial prefrontal cortex as well as (c) the border areas between (a) and (b). CONCLUSION Psychometric intelligence is associated with WM-induced changes in functional connectivity, influencing the way in which WM key nodes dynamically modulate the interaction with other brain nodes in response to WM.