Patients with blindsight have damage to the system that produces visual perception (the visual cortex of the brain and some of the nerve fibers that bring information to it from the eyes) rather than to the underlying brain system controlling eye movements.[13] The phenomenon was originally thought to show how, after the more complex perception system is damaged, people can use the underlying control system to guide hand movements towards an object even though they cannot see what they are reaching for.[13] Hence, visual information can control behavior without producing a conscious sensation. This ability of those with blindsight to act as if able to see objects that they are unconscious of suggested that consciousness is not a general property of all parts of the brain, but is produced by specialized parts of it.