Magnetic resonance imaging of human intracortical structure in vivo.

Current neuroimaging methodologies have lacked the resolution needed to visualize cortical organization at the microscopic level. As a consequence, when neurological diseases disrupt the internal structure of the cerebral cortex, the changes can only be visualized postmortem, by histological examination. This imposes severe limitations in the in vivo diagnosis and investigation of those conditions. Here, we report on a magnetic resonance technique that permitted the visualization of some features of cerebral cortex in 14 living human subjects and in 2 fixed brains. The key finding was a periodic pattern of low- and high-signal slabs, oriented perpendicularly to the pial surface, that seem to correspond, respectively, to columnar modules and myelin septa. The key parameters of the new protocol included modifications in pulse sequence, field of view, number of repetitions, and plane of sectioning.