Chapter 4 describes efforts to create a prosthetic device that could provide vision to previously blind people. The device would electrically stimulate the visual cortex, using patterns of stimulation sent by a head-mounted camera. One of the research groups working on this technology, at the Illinois Institute of Technology, has a website explaining how this technique could work.

Recent evidence from brain imaging studies implies that visual cortex can be "recruited" by other sensory modalities when normal ocular input to visual cortex is lost, due to eye disease. This news story describes one such study, and this website summarizes another.

Dyslexia is a developmental disorder characterized by difficulties with accurate and/or fluent word recognition. While not necessarily the cause of dyslexia, abnormalities in the visual cortex seem to be associated with the occurrence of the condition according to a Stanford University brain imaging study.