p588fig16.18 Simulations of coordinated learning of grid cell receptive fields (second row) and unimodal place cell receptive fields (third row) by the hierarchy of SOMs in the GridPlaceMap model.  Note the exquisite regularity of the hexagonal grid cell firing fields.<BR>||  [stripe, grid, place] cells vs [spikes on trajectory, unsmoothed rate map, smoothed rate map].