Top figures: A representation of the simulated cortical surface. Open squares represent the sites of input of uncorrelated white noise. The filled square is the reference point from which cross-correlations are calculated with respect to the rest of the field. Top left: maximum positive cross-correlations. Top right: delay associated with maximum cross-correlation.
Middle figures: The first and second principal eigenmodes of activity on the simulated cortical surface, obtained from the same data used to generate the top figures.
Bottom figures: Schematic ``freeze frame'' images of potentials (or pulse densities) on the simulated cortical surface seen when the twin inputs are sine waves, of any single frequency. Bottom left: potentials in the field when the sine waves are in phase. Bottom right: potentials in the field when the sine waves are of reverse phase.