Banks of the calcarine sulcus (fissure) in the medial occipital lobe. Mostly buried within the sulcus — only ~30% visible on the cortical surface.

Koniocortex — densely packed granular cortex with prominent layer IV subdivided into IVa, IVb, IVcα, IVcβ. The line of Gennari (visible to naked eye) is a band of myelinated axons from the lateral geniculate nucleus (LGN) terminating in layer IVb — hence 'striate' cortex. Contains complete retinotopic map of contralateral visual hemifield. Ocular dominance columns alternate input from left and right eyes.