Laminar effective connectivity of the default mode network assessed using 7T fMRI

High-resolution fMRI presents opportunities in the study of fine-scale functional architecture, such as directional interactions between cortical layers. The Default Mode Network (DMN) is a major network in the brain associated with many social behaviors, however, little is known about the feed-forward and feedback information flow between different layers in regions of the DMN. We used high-resolution fMRI combined with effective connectivity to investigate the layer-to-layer interactions of regions in the DMN including medial prefrontal cortex, posterior cingulate cortex, and inferior parietal cortex. The results suggest that the middle layers of PCC are dominant in information flow within the DMN.