Anatomy of V1 relevant to the LGS model. Two streams of inputs reach the supragranular layers. One mapping, via lamina 4C then the infragranular layers, supplies a global retinotopic mapping. A second stream of inputs, via 4C then 4A and 4B, supplies a local mapping of the visual hemi-field. The black circles in lamina 4A and 4B represent the dense patches of terminating fibres seen empirically.