Hypercolumns

Higher-order modularity exists in the main visual cortex. Calling a hypercolumn as shown in figure represents a given corresponding place for both the retinas, and maps every orientation for that place. It consists of a full thickness slab of cortex with a region of about 1 mm2 having an entire set of orientation columns for both the ipsilateral and contralateral ocular dominance. The retinotopic map in V1 takes place as adjacent pixels of the retina map to adjoining columns in an orderly fashion.

Figure: Modular structure of the main visual cortex. The cortical layers are designated by Roman numerals. Here, I=ipsilateral; and C=contralateral