What we have learned about human primary visual cortex from high resolution functional magnetic resonance imaging

Abstract

This article reviews our exploration of structures and functions of the human visual cortex using high resolution (submillimeter) functional magnetic resonance imaging (fMRI). It discusses factors that restrict the spatial resolution of blood oxygenation-level dependent (BOLD) fMRI–the point-spread function of the BOLD signal, limited by both imaging techniques to be used and neurovascular units to be studied, and the signal-tonoise ratio. I offer personal thoughts regarding optimal solutions for dealing with these issues, summarize techniques we have developed over the years for using high resolution fMRI to visualize functional architectures and explore physiological properties in the primary visual cortex of humans, including choices of imaging hardware and pulse sequences, experimental procedures, and stimulation paradigms, and finally offer my personal opinions regarding the future of high resolution fMRI.