Commonly held wisdom says that processing of visual features such as lines, forms, and motion is limited to higher cortical areas (for example, the medial temporal lobe, or area MT). Recent research shows, however, that the retina itself can extract motion signals, underscoring the subtle computational prowess of the bit of your brain that lives in your eye.
1. Baccus, S. A., Olveczky, B. P., Manu, M. & Meister, M. (2008) A Retinal Circuit That Computes Object Motion. The Journal of Neuroscience, 28(27):6807-6817