Cortical surface-based analysis - II: Inflation, flattening, and a surface-based coordinate system

The surface of the human cerebral cortex is a highly folded sheet with the majority of its surface area buried within folds. As such, it is a difficul t domain for computational as well as visualization purposes. We have there fore designed a set of procedures for modifying the representation of the c ortical surface to (i) inflate it so that activity buried inside sulci may be visualized, (ii) cut and flatten an entire hemisphere, and (iii) transfo rm a hemisphere into a simple parameterizable surface such as a sphere for the purpose of establishing a surface-based coordinate system. (C) 1999 Aca demic Press.