Intelligence and Cognitive Flexibility Selectively Modulate Working Memory Functioning

Working memory is a key component of intelligence, which can be underpinned by task connectome, while cognitive flexibility plays a role in adaptive and executive function that supports working memory processes. However, it remains unknown how intelligence and cognitive flexibility modulate working memory functioning, in terms of behavioural performance and task-related brain hierarchy. Current study investigated the working memory task-related behaviour and brain connectomic gradient in healthy adults together with their intelligence and cognitive flexibility measures. Results showed cognitive flexibility and intelligence were not significantly correlated with each other but with working memory function. Principal component and partial least square analysis revealed that nearly half of variance was explained by their overlap component, which linked with task gradient values of frontoparietal and ventral attention network representing executive, control and cognitive functioning. Individuals with higher intelligence and cognitive flexibility showed less distance between frontoparietal/ventral attention network and unimodal regions in gradient axis during working memory performance. Further analyses demonstrated that task gradient of frontoparietal and ventral attention network was significantly associated with working memory function, and selectively mediated by cognitive flexibility and intelligence, which may suggest partly convergent neural mechanisms for higher order functions that are involved in working memory functioning. In conclusion, current study provides new insight into the relationship among task connectomic gradient, working memory, intelligence, and cognitive flexibility, which helps understand the multi-component model of working memory and underlying task gradient principle.