White matter connections within the central sulcus subserving the somato-cognitive action network

The somato-cognitive action network (SCAN) consists of three nodes interspersed within Penfield's motor effector regions. The configuration of the somato-cognitive action network nodes resembles the one of the 'plis de passage' of the central sulcus: small gyri bridging the precentral and postcentral gyri. Thus, we hypothesize that these may provide a structural substrate of the somato-cognitive action network. Using microdissections of 16 human hemispheres, we consistently identified a chain of three distinct plis de passage with increased underlying white matter in locations analogous to the somato-cognitive action network nodes. We mapped localizations of plis de passage into standard stereotactic space to seed functional MRI connectivity across 9000 resting-state functional MRI scans, which demonstrated the connectivity of these sites with the somato-cognitive action network. Intraoperative recordings during direct electrical central sulcus stimulation further identified inter-effector regions corresponding to plis de passage locations. This work provides a critical step towards an improved understanding of the somato-cognitive action network in both structural and functional terms. Furthermore, our work has the potential to guide the development of refined motor cortex stimulation techniques for treating brain disorders and operative resective techniques for complex surgery of the motor cortex.