Gray Matter Volume in Different Cortical Structures Dissociably Relates to Individual Differences in Capacity and Precision of Visual Working Memory

Visual working memory (VWM) refers to our ability to selectively maintain visual information in a mental representation. While cognitive limits of VWM greatly influence a variety of mental operations, it remains controversial whether the quantity or quality of representations in mind constrains VWM. Here, we examined behavior-to-brain anatomical relations as well as brain activity to brain anatomy associations with a "neural" marker specific to the retention interval of VWM. Our results consistently indicated that individuals who maintained a larger number of items in VWM tended to have a larger gray matter (GM) volume in their left lateral occipital region. In contrast, individuals with a superior ability to retain with high precision tended to have a larger GM volume in their right parietal lobe. These results indicate that individual differences in quantity and quality of VWM may be associated with regional GM volumes in a dissociable manner, indicating willful integration of information in VWM may recruit separable cortical subsystems.