A new sulcal landmark identifying anatomical and functional gradients in human lateral prefrontal cortex

Understanding the relationship between anatomy and function in portions of human cortex that are expanded compared to other mammals such as lateral prefrontal cortex (LPFC) is of major interest in cognitive neuroscience. Implementing a multi-modal approach and the manual definition of nearly 800 cortical indentations, or sulci, in 72 hemispheres, we report a new sulcal landmark in human LPFC: the posterior middle frontal sulcus (pmfs). The pmfs is a shallow tertiary sulcus with three components that differ in their myelin content, resting state connectivity profiles, and engagement across meta-analyses of 83 cognitive tasks. These findings support a classic, largely unconsidered anatomical theory that tertiary sulci serve as landmarks in association cortices, as well as a modern cognitive neuroscience theory proposing a functional hierarchy in LPFC. As there is a growing need for computational tools that automatically define tertiary sulci throughout cortex, we share pmfs probabilistic sulcal maps with the field.