Retinal Coding for Vernier Acuity and Motion

Abstract

The neuronal processes subserving vision can certainly be understood as being the result of an interaction between simple agents and therefore as processes underlying prerational intelligence. There are very many cells (e. g. , 100 000 rods and cones per eye) but only a few cell types in the initial stages of the neural pathway devoted to conscious vision in humans. These are the cones and rods, the horizontal cells, the bipolar cells, the amacrine cells, and finally the retinal ganglion cells, which are described here in more detail. These connect to the relay cells going from the corpus geniculatum laterale (CGL) into the primary visual cortex. Here we find three different anatomical cell types most of them being orientation selective neurons. These and many other nerve cells further up in the visual pathways of the brain participate in the processing of signals in visual tasks, two of which hyperacuity and motion perception — are chosen here for closer inspection. Hyperacuity is the ability of human observers to discriminate the relative position, orientation or curvature of spatially extended objects with a precision surmounting by up to one order of magnitude the spatial resolution defined through the grid of retinal cones. There are no cells in the retina explicitly carrying hyperacuity signals, hence this task must be solved in the cortex.