Mnemonic maps of visual space in human prefrontal cortex

Abstract

Neural theories of how the prefrontal cortex (PFC) supports working memory rely on evidence from decades of pioneering macaque research. In some respects, efforts to translate these animal models of working memory in human PFC using neuroimaging have largely failed. One possible explanation, before concluding key non-homologies between the species, is that previous neuroimaging studies used resolutions too coarse to be sensitive to intermixed distributions of neurons tuned to memorized features. To resolve this concern, we scanned human PFC at 900 micron resolution using 7T fMRI. We found that population activity in retinotopically-organized superior precentral sulcus-rather than the predicted midlateral PFC-persists during memory, encodes fine-grained information about memorized items, predicts behavioral errors in memory, and forms a stable subspace with a topological organization yoked to visual space. These results have important implications for both functional homologies between the species and theories of how the PFC supports working memory.