Translating functional brain activity between humans and monkeys

Abstract Comparing brain responses across species is essential for identifying models of human cognition and testing theories of brain evolution, but differences in brain size, measurement techniques, and signal dynamics make it challenging. Here we collected dense fMRI data in macaques and humans using the same movies, static-image sequences, and tasks, and developed a multivariate analysis method that aligns neural representations temporally and spatially. The resulting data-driven framework provides a quantitative translation of brain responses among individuals and between species. Using this framework, we uncovered a broadly conserved cross-species hierarchy of retinotopic visual areas and whole-brain correspondence. Yet within this structure, we found that higher-order macaque areas shared more information with lower-order human areas, particularly during movies, providing evidence of species differences. We also identified potential macaque precursors to human regions involved in high-level cognition, including theory-of-mind and reading. These results offer a blueprint for common representational principles across species.