Ventromedial Prefrontal Cortex

Population Masks of the Architectonic Areas within Human vmPFC in MNI-space

Symmetric and asymmetric population masks of human architectonic areas within Human vmPFC in MNI-space: 25, 24 32, 14c, 14r, 14r’, 14m and 11m (Mackey and Petrides, in press) based on a comparative cytoarchitectonic study of the ventral frontal cortex in humans and macaques (Mackey and Petrides, 2010).

Methods

The locations of the architectonic areas were manually identified by digital masks using Display on the anatomical MRIs of four of the brains (8 hemispheres) that were subsequently prepared for histological examination (in Mackey & Petrides, in press). The anatomical MRIs and the masks representing the different architectonic areas were linearly translated into the Montreal Neurological Institute stereotactic space (MNI-space) (Evans et al., 1992; Evans et al., 1993; Collins et al., 1994).

The individual masks were added together to create population masks where the value of each voxel is determined by the number of hemispheres that contain the specified architectonic area. Two sets of population masks per architectonic area were created: an asymmetric and a symmetric mask. In the symmetric masks, areas in one hemisphere are reflected onto the opposite side of the brain and vice versa so that area masks in all 8 hemispheres (4 left and 4 right) may be visualized together on each side of the brain (i.e. voxels range in value from 0 to 8). In the asymmetric masks, the left and right hemisphere masks are presented in their original locations, 4 masks in the left hemisphere and 4 masks in the right hemisphere. (i.e. voxels range in value from 0 to 4).