Microstructural organization of superior longitudinal fasciculus and cingulum bundle support metacognition driven cognitive offloading.

People often use external tools to offload cognitive demands associated with remembering future intentions. While previous research has established a causal role of metacognition in cognitive offloading, the neural basis of white matter tracts supporting this metacognitive control process remains unclear. To address this, we conducted a study with 34 participants using diffusion tensor imaging (DTI) to examine how white matter connectivity supports metacognition driven cognitive offloading. Behaviorally, we replicated prior findings showing that under-confidence in internal memory predicts a bias toward using external reminders. At the neural level, we used diffusion tensor imaging to quantify fractional anisotropy (FA), a measure of microstructural integrity in white matter. We found the microstructural integrity of the superior longitudinal fasciculus (SLF) and cingulum bundle (CB) predicted deviations from the optimal use of reminders. The microstructural integrity of the fornix negatively predicted participants' confidence in performing the task when restricted to internal memory. Our findings reveal the microstructural organization of the white-matter tracts in the fronto-temporal-parietal network are related to metacognition driven cognitive offloading. We discuss several aspects of metacognition driven cognitive offloading from a white matter microstructural perspective.