It must have the right orientation, the right position, and the right size. Simple cell receptive fields could be 'built' in the cortex by collecting responses from LGN cells whose receptive fields fall along a line across the retina, but the exact wiring is still the subject of debate. Back to V1 V1 Architecture Hubel and Wiesel were the first to discover that cells in V1 are arranged in a beautifully precise and orderly fashion. Orientation tuning is a prominent feature of individual cell responses, as described elsewhere . Hubel and Wiesel found that as one advances deeper into the cortex through successive layers perpendicular to the surface, all cells that have orientation tuning prefer the same orientation.
Some cells prefer the right eye, and others prefer the left eye.
When V1 is stained for cytochrome oxidase, an enzyme involved in metabolism, distinct blobs show up which are most clearly seen in layers 2 and 3. The blobs are arranged in rows that line up above the centres of the ocular dominance columns in Layer 4, thus the blobs are about 0.5mm apart. They are also about 0.25mm wide. These results have led to speculation that blobs form part of a colour analysis 'stream' in the visual system that passes through V1 blobs, V2 thin stripes, and on to V4 . Back to V1 V2 Area V2 has a long common border with V1.