Quantitative Assessment of the Local and Long-Range Horizontal Connections within the Striate Cortex

We present a quantitative assessment of the local and long-range horizontal connections within two separate models of layer 4 and layer 2/3 of the striate cortex. Connections between the orientation minicolumns, building the models, are developed during exposure to visual input. Layer 4 long-range horizontal connections target all orientation domains in a balanced manner, whereas local connections are biased towards the isoorientation domain. However, both local and long-range horizontal connections of the layer 2/3 network are biased towards the iso-orientation domains. We hypothesize that the patchy layout of the layer 2/3 longrange connections is a consequence of excitatory cells targeting mainly other excitatory cells located in distal iso-orientation domains. Furthermore, both networks demonstrate dense local and sparse distal connectivity.