2015 Volume 36 Issue 3 Pages 51-55
Functional magnetic resonance imaging (fMRI) is one of the main methods for the study of visual function in the human brain. fMRI can measure human brain activation noninvasively by detecting the blood oxygenation level dependent (BOLD) signal, which reflects changes in the deoxyhemoglobin concentration accompanying neural activation. This signal, however, is an indirect measure of neural activation, so we have to be careful in designing experiments and analyzing data to interpret the signal as brain activation. In this review, principles of MRI and fMRI measurements and characters of their signals are explained with several notes regarding spatial and temporal resolution and experimental design. As an example of functional brain imaging with fMRI, retinotopic mapping and separation of the early visual fields are shown.
