Seeing patterns through the hemodynamic veil--the future of pattern-information fMRI.

Pattern-information fMRI (pi-fMRI) has become a popular method in neuroscience. The technique is motivated by the idea that spatial patterns of fMRI activity reflect the neuronal population codes of perception, cognition, and action. In this commentary, we discuss three fundamental outstanding questions: (1) What is the relationship between neuronal patterns and fMRI patterns? (2) Does pattern-information fMRI benefit from hyperacuity, enabling the investigation of columnar-level neuronal information, even at low resolution? (3) Do high-resolution and high-field fMRI increase sensitivity to pattern information? The empirical answers will enable us to optimize pi-fMRI data acquisition and to understand the ultimate potential and appropriate interpretation of pi-fMRI results. Furthermore, considering the relationship between neuronal activity and fMRI at the level of spatiotemporal patterns provides a novel and important perspective on the basis of the fMRI signal.