Visual Prosthesis
C. The use of implanted electrode arrays

Since in the striate cortex (area V1) of primates the visual field is laid out in a beautiful topographic order, it has been proposed that the images in the visual field can generate a spatially corresponding layout on the cortical surface which can thereby serve to convey the shape of images in the world. There are several problems with this view. First of all, as shown earlier on this website, the projections from the retina as such that the right visual hemifield ends up being represented in the left side of the brain and the left visual hemifield in the right side. Thus central viewing of a single object results in half of it impinging in the left and half on the right hemisphere in area V1. Integration of such images are therefore likely to occur in higher visual areas. The second problem is the magnification factor involved. In area V1 much more space is allocated to central than to peripheral vision.