fusiform gyrus

Oliver Sacks: When a part of the brain that is used to a sensory input, whether it is visual or auditory, isn't getting it, then it tends to become hyperactive and to generate activity on its own. In the case of musical hallucinations, with [people who go deaf], the brain delves into its memories of music, and so people hallucinate pieces of music, sometimes just a few bars.
The visual ones [in people who go blind] are different. People never recognize the figures or places they see. They're not like bits of memory. They're sort of strange inventions in a way, which the visual brain comes up with…
UPDATE: During his TED talk this morning, Sacks elaborated on the kinds of hallucinations his patients have had and the parts of the brain that are activated when they're seeing them. Some of his patients who see faces see them distorted with large eyes or teeth. He said there's a part of the brain specifically devoted to recognizing teeth and eyes, and this part of the brain is being affected when the patients see these exaggerated details. One patient saw cartoons -- in particular images of Kermit the Frog. Sacks says there's a part of the brain that is specific to recognizing cartoons. Ditto with cars. The latter can be so precise as to be devoted to recognizing specific cars, such as an Aston Martin. February 05, 2009 | 7:21:22 AM By Kim Zetter

Eyes teeth cars hats cartoons